JFK Assassination Forum
JFK Assassination Discussion & Debate => JFK Assassination Discussion & Debate => Topic started by: Michael T. Griffith on September 26, 2020, 01:41:38 AM
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Here is the newly revised and expanded version of my 2013 article on the HSCA acoustical evidence:
The HSCA’s Acoustical Evidence: Proof of a Second Gunman in the JFK Assassination
https://miketgriffith.com/files/hscaacous.pdf
Anyone who has read the 2013 version will see that the new version is very different and much more detailed. Here are the section headings in the new version:
Introduction
The NRC Panel
The Motorcycle with the Open Microphone
No “Audible” Shots on the Dictabelt Tape
How Could the Grassy Knoll Shot Have Missed?
Crowd Noise and the Carillon Bell
The Decker “Hold Everything” Crosstalk
Larry Sabato’s Sonalysts Study
The Grassy Knoll Shot and the Zapruder Film
Five Gunshots on the Dictabelt Tape?
A Summary of the Acoustical Evidence
Bibliography
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Thanks for sharing your article Michael Thumb1: Its subtitle could be "The acoustical evidence for dummies" as it starts with the basics, it's a great introduction into this complicated matter.
Two quick questions:
1) Would shots fired using silencers show up on the Dictabelt as N-waves?
2) The grassy knoll shot. Dr. David Mantik writes that a second headshot was fired not from the grassy knoll, but from the storm drain on the north overpass. This according to his interpretation of the medical evidence. It can't be both (I assume), so which is it?
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Thanks for sharing your article Michael Thumb1: Its subtitle could be "The acoustical evidence for dummies" as it starts with the basics, it's a great introduction into this complicated matter.
Two quick questions:
1) Would shots fired using silencers show up on the Dictabelt as N-waves?
No. In fact, they would not show up at all, because of their vastly reduced amplitude and because of the engine noise.
2) The grassy knoll shot. Dr. David Mantik writes that a second headshot was fired not from the grassy knoll, but from the storm drain on the north overpass. This according to his interpretation of the medical evidence. It can't be both (I assume), so which is it?
This is one of the many reasons that the Dealey Plaza test firing should have included shots fired from more than just two locations and should have included many more microphones. Many researchers have noted that one of the impulse patterns might have come from the Dal-Tex Building, where Mafia man Eugene Brading was arrested minutes after the shooting, and if test shots had been fired from there, correlations to one of those testshots might have been found on the police tape.
When we look at the acoustical evidence, we need to constantly keep in mind that the test firing was limited to two firing positions.
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Went straight to the Decker cross talk section and saw that you continue talking through your ass. The tapes are in sync whenever there's cross talk which you still don't get.
Whaaat???!!! LOL! This howler is further proof that you have no business talking about the acoustical evidence. No, the tapes are not in sync whenever this is crosstalk. The crosstalk transmissions don't even synchronize with each other, for crying out loud. How can you not know this? Don't you ever get tired of embarrassing yourself with gaffe after gaffe?
The offset BS from your fake Jesus, Dr. Thomas, can't save you.
How in the world would you know, Mr. "I Can't Understand Herb Blenner"? No credible student of the acoustical evidence denies that there are offsets between the crosstalk on the two channels. The debate is over the cause of the offsets.
I guess it did not occur to you that the offsets disprove your claim that the channels synchronize whenever there is crosstalk.
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The BBN started with the noblest of intentions and ended as a farce.
It was thought, that analyzing the Dictabelt tape, they could deduce:
1. The position of the shooter.
2. The position of where the shot was aimed at, that is, where it stuck.
3. The position of the motorcycle with the stuck microphone.
Going into this, I sure Dr. Barger had hopes of getting excellent data. And if this excellent data showed the motorcycle was elsewhere, or was at Dealey Plaza but recorded three shots from the TSBD, that would be a disappointment. But, if he discovered multiple firing locations, it would be the greatest scientific crime discovery of the century. I am certain his hopes were up.
So, they ran some firing tests in Dealey Plaza on August 20, 1978, and recorded the shots on 36 microphones arranged along Houston and Elm Street.
Below is a simplified version of BBN’s Exhibit F-367, which shows the correlations that they discovered.
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| A | 136.20 |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| D | 137.70 | 176 | TSBD | Location-z 313 |
| E | 137.70 | 176 | KNOLL | Location- Tague |
| |
| |
| |
| G | 139.27 | 205 | TSBD | Location-z 313 |
| I | 139.27 | 205 | TSBD | Location-z 313 |
| J | 139.27 | 205 | KNOLL | Location-z 313 |
| |
| |
| |
| K | 140.32 | 224 | TSBD | Location-z 313 |
| |
| |
| |
| L | 145.15 | 313 | KNOLL | Location-z 313 |
| M | 145.15 | 313 | TSBD | Location-z 224 |
| N | 145.15 | 313 | TSBD | Location-z 313 |
| |
| |
| |
| O | 145.61 | 321 | TSBD | Location-z 313 |
| P | 145.61 | 321 | TSBD | Location- Tague |
| Q | 145.61 | 321 | TSBD | Location-z 224 |
| |
| |
| |
| R | 146.30 |
The “Zap. Frames” are Dr. Thomas’s estimate, not the original BBN estimate. They don’t differ by enough to make much of a difference so to avoid confusion, I just went with Dr. Thomas’s time estimate.
On this table, I don’t differentiate between the rifle in the TSBD being 2 feet behind the plane of the window, or sticking out further. It didn’t seem to make a lot of difference in the firing tests. So, I just consider these shots to be from the TSBD.
In the August 20, 1978 firing tests, they fired at four locations. Target 1, 2, 3 and 4.
Target 1 is about where the limousine was at the location shown in Zapruder frame z155.
Target 2 is about where the limousine was at the location shown in Zapruder frame z224.
Target 3 is about where the limousine was at the location shown in Zapruder frame z313.
Target 4 is about Mr. Tague was standing, about 240 feet beyond the z313 location.
So instead of listing the “Target Location” as “3”, I give it as “Location-z 313”.
So, how did they do?
1. The position of the shooter.
Terrible.
Shot 1 at z176 - They got correlations found for both the TSBD and the Grassy Knoll. There should have only been a correlation for one location. One of these results must be bad. The degree of correlation was not high enough,
Shot 2 at z205 – Again, bad, correlations found for both the TSBD and the Grassy Knoll.
Shot 3 at z224 – One correlation for a shot from the TSBD. Getting just one correlation is actually good. It’s too bad they didn’t get this for all 5 shots.
Shot 4 at z304 – Again, bad, correlations found for both the TSBD and the Grassy Knoll.
Shot 5 at z313 – Correlations only for a shot from the TSBD. This is a good result.
2. The position of where the shot was aimed at, that is, where it stuck.
Shot 1 at z176 – the shot struck at:
Location-z 155 – miss by 19 feet.
Location-z 313 – miss by 132 feet.
Location- Tague – miss by 272 feet.
Shot 2 at z205 – the shot struck at:
Location-z 313 – miss by 92 feet.
Shot 3 at z224 – the shot struck at:
Location-z 313 – miss by 75 feet.
Shot 4 at z304 – the shot struck at:
Location-z 224 – miss by 70 feet.
Location-z 313 – a hit on the limousine
Shot 5 at z313 – the shot struck at:
Location-z 224 – miss by 75 feet.
Location-z 313 – a hit on the limousine
Location- Tague – miss by 240 feet.
One the whole, terrible. The data contradicts itself. Clearly false correlations are more common than true.
Dr. Barger doesn’t seem the least bit phase. When the results contradict themselves, we should just assume we got some “false alarms”. We should just ignore the ones that don’t make sense and consider the ones that do reliable. These “false alarms” are a serious problem. They are more properly known as “false positives”. So many false positives in the data, where false positives are more common then true positives, bring all the true positives into doubt.
And if we follow Dr. Barger, throw out all the “false alarms”, what proposed shots have good support:
Shot 1 – at z152 – good support (a miss by 19 feet is good enough), if the two false positives are ignored.
Shot 2 – at z205 – no support, all correlations give unbelievable “Target location” that is off by 92 feet.
Shot 3 – at z224 – no support, the correlation gives unbelievable “Target location” that is off by 75 feet.
Shot 4 – at z304 – good support, if the two false positives are ignored.
Shot 5 – at z313 – good support, if the two false positives are ignored.
Two of the five “found” shots, strictly speaking, should be thrown out, because misses by 70 feet or more is just too unbelievable.
3. The position of the motorcycle with the stuck microphone.
Here we have much better correlations. These correlations are what Mr. Griffith really likes to emphasis.
The data is consistent with a motorcycle traveling at around 11 mph, trailing behind the limousine by 120 to 160 feet. Which should plausible. But there is a problem with the film evidence. The Hughes film shows the only possible officer, Officer McLain, along with his partner, Officer Baker, trailing behind the limousine by 300 feet. By the time the film shuts off, Officer McLain has 1.5 seconds to cover 170 feet, impossible. Also, he should appear in the Altgens photograph.
But let’s ignore all that. We still, seemingly, have a remarkable correlation with the data and a plausible set of positions of the motorcycle. What are we to make of this data as a whole? Random looking correlations for the position of the shooter and the area of the street the bullets struck. Good correlation for the position of the motorcycle. This is truly hot ice and wondrous strange snow.
But there is a simple explanation. For a through check of all possible correlations:
432 strip charts from the 1978 firing tests, 36 microphones times 12 test shots
Need to be each compared with the 6 possible shots from the 1963 Dictabelt recording.
So, 2,592 comparisons need to be made between pairs of strip charts for the 1978 tests and the 1963 recording.
This sounds difficult to do in 15 days, to get done in time to present the data to the HSCA. They have to:
Decide which of the 1978 78 test shots are to be compared, they selected 12 of them.
Print out 12 strip charts for them.
Print out 432 strip charts for the 1978 data.
Make all 2,592 comparisons, which involve counting waves within a certain number of milliseconds and doing some calculations to get a “correlation coefficient”
Organize all the data and print them out in a neat form to present to the HSCA.
I would suggest that maybe they did not perform all 2,592 combinations of comparisons. From one shot, it seemed the motorcycle was 150 feet behind. With the time limit, it made sense to only search for where the motorcycle might be. Why search the data from a stretch of street that you probably wouldn’t find a motorcycle. And if a correlation was found about where expected, 150 feet behind, under the time pressure, it’s time to move on to the next shot.
If something like this happened, all the correlations found would be consistent with a motorcycle averaging 11 mph, 120 to 160 feet behind the limousine. Even if a through processing of the entire data set may have found many contradictions on the location of the motorcycle, just as was found with the location of the shooter and the location of the target.
Until proven otherwise, I hold that this is the most likely scenario that explains this “hot ice and wondrous strange snow” results.
Dr. Barger’s fundamental error, is that he allowed his hopes to affect his judgement. These “false alarms”, should have set off a real alarm in his head. It should have been apparent to him that he was measuring “noise”, garbage data that contradicted itself which was what data is that contains too many false positives. This work will be his legacy, it will overshadow everything else he was done in his career. He has gone from being a respected scientist to having an insect expert as his main ally.
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This is one of the many reasons that the Dealey Plaza test firing should have included shots fired from more than just two locations and should have included many more microphones. Many researchers have noted that one of the impulse patterns might have come from the Dal-Tex Building, where Mafia man Eugene Brading was arrested minutes after the shooting, and if test shots had been fired from there, correlations to one of those testshots might have been found on the police tape.
When we look at the acoustical evidence, we need to constantly keep in mind that the test firing was limited to two firing positions.
What do you do if these expanded firing tests find that the shot at 139.27 (z205) came from the TSBD, the Grassy Knoll and the Dal-Tex building?
Which of the three “confirmed” firing locations should be considered accurate for that shot?
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2) The grassy knoll shot. Dr. David Mantik writes that a second headshot was fired not from the grassy knoll, but from the storm drain on the north overpass. This according to his interpretation of the medical evidence. It can't be both (I assume), so which is it?
This is one of the many reasons that the Dealey Plaza test firing should have included shots fired from more than just two locations and should have included many more microphones. Many researchers have noted that one of the impulse patterns might have come from the Dal-Tex Building, where Mafia man Eugene Brading was arrested minutes after the shooting, and if test shots had been fired from there, correlations to one of those testshots might have been found on the police tape.
When we look at the acoustical evidence, we need to constantly keep in mind that the test firing was limited to two firing positions.
Yes. The BBN confirmed that the shot at z304 (their estimate of time) came from the grassy knoll. And Acoustics analysts Mark Weiss and Ernest Aschkenasy confirmed that there was a 95% chance that the shot from the grassy knoll. But with a shooting tests from the sewer, this may have confirmed that the z304 shot did indeed come from the TSBD, and the grassy knoll, and from the sewer.
I don’t think they needed more shooting locations. I think they needed less, to reduce the number of these pesky false positives.
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The BBN started with the noblest of intentions and ended as a farce.
It was thought, that analyzing the Dictabelt tape, they could deduce:
1. The position of the shooter.
2. The position of where the shot was aimed at, that is, where it stuck.
3. The position of the motorcycle with the stuck microphone.
Going into this, I sure Dr. Barger had hopes of getting excellent data. And if this excellent data showed the motorcycle was elsewhere, or was at Dealey Plaza but recorded three shots from the TSBD, that would be a disappointment. But, if he discovered multiple firing locations, it would be the greatest scientific crime discovery of the century. I am certain his hopes were up.
So, they ran some firing tests in Dealey Plaza on August 27, 1978, and recorded the shots on 36 microphones arranged along Houston and Elm Street.
Below is a simplified version of BBN’s Exhibit F-367, which shows the correlations that they discovered.
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| A | 136.20 |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| D | 137.70 | 176 | TSBD | Location-z 313 |
| E | 137.70 | 176 | KNOLL | Location- Tague |
| |
| |
| |
| G | 139.27 | 205 | TSBD | Location-z 313 |
| I | 139.27 | 205 | TSBD | Location-z 313 |
| J | 139.27 | 205 | KNOLL | Location-z 313 |
| |
| |
| |
| K | 140.32 | 224 | TSBD | Location-z 313 |
| |
| |
| |
| L | 145.15 | 313 | KNOLL | Location-z 313 |
| M | 145.15 | 313 | TSBD | Location-z 224 |
| N | 145.15 | 313 | TSBD | Location-z 313 |
| |
| |
| |
| O | 145.61 | 321 | TSBD | Location-z 313 |
| P | 145.61 | 321 | TSBD | Location- Tague |
| Q | 145.61 | 321 | TSBD | Location-z 224 |
| |
| |
| |
| R | 146.30 |
The “Zap. Frames” are Dr. Thomas’s estimate, not the original BBN estimate. They don’t differ by enough to make much of a difference so to avoid confusion, I just went with Dr. Thomas’s time estimate.
On this table, I don’t differentiate between the rifle in the TSBD being 2 feet behind the plane of the window, or sticking out further. It didn’t seem to make a lot of difference in the firing tests. So, I just consider these shots to be from the TSBD.
In the August 27, 1978 firing tests, they fired at four locations. Target 1, 2, 3 and 4.
Target 1 is about where the limousine was at the location shown in Zapruder frame z155.
Target 2 is about where the limousine was at the location shown in Zapruder frame z224.
Target 3 is about where the limousine was at the location shown in Zapruder frame z313.
Target 4 is about Mr. Tague was standing, about 240 feet beyond the z313 location.
So instead of listing the “Target Location” as “3”, I give it as “Location-z 313”.
So, how did they do?
1. The position of the shooter.
Terrible.
Shot 1 at z176 - They got correlations found for both the TSBD and the Grassy Knoll. There should have only been a correlation for one location. One of these results must be bad. The degree of correlation was not high enough,
Shot 2 at z205 – Again, bad, correlations found for both the TSBD and the Grassy Knoll.
Shot 3 at z224 – One correlation for a shot from the TSBD. Getting just one correlation is actually good. It’s too bad they didn’t get this for all 5 shots.
Shot 4 at z304 – Again, bad, correlations found for both the TSBD and the Grassy Knoll.
Shot 5 at z313 – Correlations only for a shot from the TSBD. This is a good result.
2. The position of where the shot was aimed at, that is, where it stuck.
Shot 1 at z176 – the shot struck at:
Location-z 155 – miss by 19 feet.
Location-z 313 – miss by 132 feet.
Location- Tague – miss by 272 feet.
Shot 2 at z205 – the shot struck at:
Location-z 313 – miss by 92 feet.
Shot 3 at z224 – the shot struck at:
Location-z 313 – miss by 75 feet.
Shot 4 at z304 – the shot struck at:
Location-z 224 – miss by 70 feet.
Location-z 313 – a hit on the limousine
Shot 5 at z313 – the shot struck at:
Location-z 224 – miss by 75 feet.
Location-z 313 – a hit on the limousine
Location- Tague – miss by 240 feet.
One the whole, terrible. The data contradicts itself. Clearly false correlations are more common than true.
Dr. Barger doesn’t seem the least bit phase. When the results contradict themselves, we should just assume we got some “false alarms”. We should just ignore the ones that don’t make sense and consider the ones that do reliable. These “false alarms” are a serious problem. They are more properly known as “false positives”. So many false positives in the data, where false positives are more common then true positives, bring all the true positives into doubt.
And if we follow Dr. Barger, throw out all the “false alarms”, what proposed shots have good support:
Shot 1 – at z152 – good support (a miss by 19 feet is good enough), if the two false positives are ignored.
Shot 2 – at z205 – no support, all correlations give unbelievable “Target location” that is off by 92 feet.
Shot 3 – at z224 – no support, the correlation gives unbelievable “Target location” that is off by 75 feet.
Shot 4 – at z304 – good support, if the two false positives are ignored.
Shot 5 – at z313 – good support, if the two false positives are ignored.
Two of the five “found” shots, strictly speaking, should be thrown out, because misses by 70 feet or more is just too unbelievable.
3. The position of the motorcycle with the stuck microphone.
Here we have much better correlations. These correlations are what Mr. Griffith really likes to emphasis.
The data is consistent with a motorcycle traveling at around 11 mph, trailing behind the limousine by 120 to 160 feet. Which should plausible. But there is a problem with the film evidence. The Hughes film shows the only possible officer, Officer McLain, along with his partner, Officer Baker, trailing behind the limousine by 300 feet. By the time the film shuts off, Officer McLain has 1.5 seconds to cover 170 feet, impossible. Also, he should appear in the Altgens photograph.
But let’s ignore all that. We still, seemingly, have a remarkable correlation with the data and a plausible set of positions of the motorcycle. What are we to make of this data as a whole? Random looking correlations for the position of the shooter and the area of the street the bullets struck. Good correlation for the position of the motorcycle. This is truly hot ice and wondrous strange snow.
But there is a simple explanation. For a through check of all possible correlations:
432 strip charts from the 1978 firing tests, 36 microphones times 12 test shots
Need to be each compared with the 6 possible shots from the 1963 Dictabelt recording.
So, 2,592 comparisons need to be made between pairs of strip charts for the 1978 tests and the 1963 recording.
This sounds difficult to do in 15 days, to get done in time to present the data to the HSCA. They have to:
Decide which of the 1978 78 test shots are to be compared, they selected 12 of them.
Print out 12 strip charts for them.
Print out 432 strip charts for the 1978 data.
Make all 2,592 comparisons, which involve counting waves within a certain number of milliseconds and doing some calculations to get a “correlation coefficient”
Organize all the data and print them out in a neat form to present to the HSCA.
I would suggest that maybe they did not perform all 2,592 combinations of comparisons. From one shot, it seemed the motorcycle was 150 feet behind. With the time limit, it made sense to only search for where the motorcycle might be. Why search the data from a stretch of street that you probably wouldn’t find a motorcycle. And if a correlation was found about where expected, 150 feet behind, under the time pressure, it’s time to move on to the next shot.
If something like this happened, all the correlations found would be consistent with a motorcycle averaging 11 mph, 120 to 160 feet behind the limousine. Even if a through processing of the entire data set may have found many contradictions on the location of the motorcycle, just as was found with the location of the shooter and the location of the target.
Until proven otherwise, I hold that this is the most likely scenario that explains this “hot ice and wondrous strange snow” results.
Dr. Barger’s fundamental error, is that he allowed his hopes to affect his judgement. These “false alarms”, should have set off a real alarm in his head. It should have been apparent to him that he was measuring “noise”, garbage data that contradicted itself which was what data is that contains too many false positives. This work will be his legacy, it will overshadow everything else he was done in his career.
Just about every single statement in your reply is either false, irrelevant, or based on a misreading/misrepresentation of the HSCA materials due to your ignorance on the subject. You've already admitted that you refuse to read Dr. Thomas's book, and it's clear that you still have not read the BBN report (if you have, one wonders how on earth you could say the things you say). How about Dr. Chambers' chapter on the acoustical evidence?
Let's just take your last paragraph, the one about false alarms. BBN and WA developed very reliable tests to distinguish between the false alarms and the gunshot impulse patterns to a degree of certainty of well over 95%. Dr. Weiss explained to one congressman who asked him if the third and fourth gunshot impulses could be "acoustical mirages" of one shot that this was impossible because the third shot--the grassy knoll shot--contained specific echo-pattern characteristics of a test-firing shot from the grassy knoll, because each echo has "its own peculiar distortion, transmission characteristics":
Mr. WEISS. No, sir; because in order for that to be true, you would have to, in effect, have had the sound of the muzzle blast transported by some means to the
location of the grassy knoll area, and there emitted as if it had originated from that point. Since every echo that was predicted corresponded to an echo arising from a sound rising from that location [in the test firing], what you would have required is that echoes otherwise generated from a shot fired, say, from the depository window, would each have had its own peculiar distortion, transmission characteristics such that by some marvelous process it occurred at the microphone, intact, and at the correct position. (5 HSCA 608)
People who understand the acoustical evidence will realize that you are still just posting paragraphs of diversionary smoke and are still avoiding the powerful, intricate correlations between the dictabelt shots and the test-firing shots. If all those gunshot impulses are merely false alarms, then you need to explain the correlations, unless you're merely going to argue that they are all amazing, staggering coincidences.
You can't explain the correlations because there is no Web article that deals with those correlations, and so you have no source from which to copy and paste to address them. That's why you keep avoiding them.
How about if you just explain one of the correlations in the acoustical evidence: the windshield-distortion correlations? The HSCA scientists realized that soundwaves passing through a motorcycle windshield would experience distortion. So they ran tests to determine the characteristics of windshield distortion. And, lo and behold, they found that the dictabelt shots that match test shots from the Book Depository all contained windshield distortions but that the dictabelt shot that match test shots from the grassy knoll contain no such distortions. My, my, my!
Try to fathom the odds that three out of four dictabelt gunshot impulses would just happen to contain windshield distortions in the first place, and then try to fathom the odds that the one gunshot impulse that should not contain those distortions would not contain them.
He has gone from being a respected scientist to having an insect expert as his main ally.
This petty, juvenile, and erroneous comment shows why you are not credible, why you are not to be taken seriously. First of all, all of the BBN acoustical scientists stood behind the acoustical evidence, not just Dr. Barger. So did Weiss and Aschkenasy. Second, your continued harping on the fact that Dr. Thomas is an entomologist ignores the fact that he is also an expert in statistics, and that Dr. Chambers, a world-renowned physicist, and Dr. Scheim, a graduate of MIT in mathematics, also support the acoustical evidence. You don't mind citing a urologist on ballistics and forensic issues, but you object when an entomologist is cited on the acoustical evidence, even though his acoustical research has been praised by Dr. Barger and other scientists.
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Question 1:
In the BBN Exhibit F-367 Table, a portion of which I show here:
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| D | 137.70 | 176 | TSBD | Location-z 313 |
| E | 137.70 | 176 | KNOLL | Location- Tague |
| |
| |
| |
Why does it show the impulse pattern at 137.70 as matching the patterns expected by shots from both the TSBD and the Grassy Knoll?
It seems to me, that at least 2 of these matches are by luck. They are flukes. And this is the explanation for 2 of the matches, why not all 3?
How about if you just explain one of the correlations in the acoustical evidence: the windshield-distortion correlations? The HSCA scientists realized that soundwaves passing through a motorcycle windshield would experience distortion. So they ran tests to determine the characteristics of windshield distortion. And, lo and behold, they found that the dictabelt shots that match test shots from the Book Depository all contained windshield distortions but that the dictabelt shot that match test shots from the grassy knoll contain no such distortions. My, my, my!
The common pattern you show, is when you cannot answer my questions, you introduce another argument from left field. So instead of dealing with the contradictions in the BBN’s own data, you bring up “windshield-distortion”.
The shots from the TSBD contain windshield-distortions but those from the grassy knoll do not?
How can anyone say that when the BBN data, for the shots at z176, z205 and z313, match the pattern predicted for both a shot from the TSBD and the grassy knoll?
Question 2:
Did the impulse patterns correspond to z176, z205 and z213 shots, show “windshield-distortions”?
This petty, juvenile, and erroneous comment shows why you are not credible,
You are constantly insulting me with every post you direct to me. I don’t do that to you. You write like a 5-year-old who is constantly having a temper tantrum. I am just asking for clarifications for why the BBN data, the Exhibit F-367 Table, appears to contradict itself so much. And you are not explaining why, either to me or the other readers.
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The common pattern you show, is when you cannot answer my questions, you introduce another argument from left field.
No, you ask me ridiculous, diversionary, irrelevant questions, and I attempt to get you to address the real issues, the same issues that the NRC panel and O'Dell and Bowles have never gotten around to addressing: the remarkable, intricate correlations between the dictabelt gunshot impulse patterns and the test-firing impulse patterns.
I have commented on your confusion about F-367 in several replies, including one very long reply where I quoted extensively from Dr. Barger's testimony where he explained F-367. But you keep ignoring what he said and keep demanding that your imagined "contradictions" be "explained."
So instead of dealing with the contradictions in the BBN’s own data,
The "contradictions" are in your mind, or else you know better but are hoping you'll fool others.
you bring up “windshield-distortion”.
Uh, yeah, because windshield distortion is a known factor in acoustical analysis, because we know from science that when soundwaves pass through a windshield, the windshield causes certain distortions in the wave and in the echo pattern. You'd know that if you had bothered to do your homework.
The shots from the TSBD contain windshield-distortions but those from the grassy knoll do not? How can anyone say that when the BBN data, for the shots at z176, z205 and z313, match the pattern predicted for both a shot from the TSBD and the grassy knoll?
How could the HSCA experts say that the TSBD shots contain windshield distortion? Because they ran tests on this to determine the patterns that would be caused by windshield distortion. From the WA report:
A different but also significant effect on the relative strengths of the recorded echoes would have been caused by the motorcycle windshield. On the DPD motorcycles, the microphone was usually mounted on a bar directly behind the windshield. Sounds arriving from the front of the motorcycle would have diffracted around the windshield and in doing so would have lost strength. As determined by experiment, the windshield of a 1960's Harley Davidson motorcycle attenuated [weakened] gunshot sounds received from in front of the motorcycle by 3 decibels to 6 decibels. The amount of attenuation [weakening, decreasing] depended on how close the microphone was to the windshield. Obviously, sounds received from the sides and rear of the motorcycle would not be affected by the windshield. (8 HSCA 30-31)
Then, when the HSCA scientists did the refined analysis, they found that the TSBD shots all contain windshield distortion but that the grassy knoll shot goes not. Dr. G. Paul Chambers, a renowned physicist who has worked with NASA, the Naval Surface Warfare Center, and the Naval Research Laboratory:
Weiss and Aschkenasy . . . also took into account muting and distortion of the acoustical signature due to the windshield of the motorcycle. When they considered this in their analysis, they found that the earlier shots determined by BBN to be from the Texas School Book Depository showed this distortion, while the acoustical sequence that matched the test shot from the grassy knoll did not exhibit this effect.
This is precisely the result expected for a microphone mounted on a motorcycle moving in Kennedy’s motorcade along Houston Street facing the Depository, where the sound of the shot from this location would pass through the windshield, but moving sideways to the direction of the grassy knoll so that a shot from this location would not need to pass through the windshield to reach the microphone. This lent further credence to the validity of their analysis. (Chambers, Head Shot: The Science Behind the JFK Assassination, p. 102)
Question 2:
Did the impulse patterns correspond to z176, z205 and z213 shots, show “windshield-distortions”?
This is a silly, disingenuous question. And I see you again put "windshield-distortions" in quotes, as if windshield distortion is not a known, scientifically established phenomenon.
You are constantly insulting me with every post you direct to me. I don’t do that to you. You write like a 5-year-old who is constantly having a temper tantrum.
You repeatedly insult and belittle Dr. Thomas, calling him "a bug guy," "an insect guy," etc., but you get upset when I call you out for making ignorant claims. I am just tired of your dishonesty, your evasion, and your misrepresentation. You have done nothing but duck and dodge and bob and weave every time I have asked you direct, clear questions about the dictabelt-test firing correlations.
I am just asking for clarifications for why the BBN data, the Exhibit F-367 Table, appears to contradict itself so much.
No you're not. You're throwing up a bunch of absurd smoke to avoid dealing with the core of the acoustical evidence. And I'm just not going to waste time playing your games. Again, I have already dealt at length with your misreading/misrepresentation of F-367.
And you are not explaining why, either to me or the other readers.
Oh, I'll let our readers decide whether or not I am "explaining why." Your silly questions are answered by the HSCA materials and in subsequent research. Your questions are based either on a surreal misreading of the HSCA materials or on a deliberate misrepresentation of them.
The HSCA scientists explained in detail how they separated the false alarms/false positives from the final candidate impulses. They explained how they screened every single impulse on the dictabelt tape. They explained how they compared the viable candidate impulse patterns to patterns of test-firing gunshots. They explained how they identified N-waves, muzzle blasts, and muzzle-blast echoes. They explained how they tested for windshield distortion. They explained how they matched the test-firing echo patterns to the gunshot impulse patterns on the dictabelt tape. Etc., etc. etc.
But you don't want to talk about any of that. You keep bringing up ancillary issues based on your misreading/misrepresentation of the HSCA materials, most of which you have not even really read. And you have defiantly announced that you will not read the most authoritative analysis of the acoustical evidence now available, i.e., Dr. Thomas's four chapters on the subject in his book Hear No Evil, even though he wrote them in close consultation with Dr. Barger.
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In the BBN Exhibit F-367 Table, a portion of which I show here:
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| D | 137.70 | 176 | TSBD | Location-z 313 |
| E | 137.70 | 176 | KNOLL | Location- Tague |
| |
| |
| |
Question 1:
Why do the impulses from three different 1978 test shots, resemble each other so closely, even though the shots are from fired from two different locations, at three different targets separated from each other by over a hundred feet?
So close that the BBN found a correlation with each of these three-test shot with the 1963 Dictabelt impulse of 137.70.
Question 2:
Shouldn’t each test shot, fired from different positions and/or fired at widely separate targets, produce its own unique wave pattern that would not be shared with other test shots?
Question 3:
How can the science of Acoustics be used to reconstruct what happened when a recorded impulse pattern correlation with different firing positions, firing at different targets?
It would seem impossible to say that “this shot was fired from this position, firing at this target”, because of Correlation “A” when Correlation “B” contradicts this.
-
********** Warning, this is not the real data, only what good data should look like **********
| |
| |
| |
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| |
| |
| |
| G | 139.27 | 205 | TSBD | Location-z 224 |
| |
| |
| |
| K | 140.32 | 224 | TSBD | Location-z 224 |
| |
| |
| |
| L | 145.15 | 313 | KNOLL | Location-z 313 |
| |
| |
| |
| O | 145.61 | 321 | TSBD | Location-z 313 |
| |
| |
| |
********** Here is the data the BBN actually got **********
| |
| |
| |
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| A | 136.20 |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| D | 137.70 | 176 | TSBD | Location-z 313 |
| E | 137.70 | 176 | KNOLL | Location- Tague |
| |
| |
| |
| G | 139.27 | 205 | TSBD | Location-z 313 |
| I | 139.27 | 205 | TSBD | Location-z 313 |
| J | 139.27 | 205 | KNOLL | Location-z 313 |
| |
| |
| |
| K | 140.32 | 224 | TSBD | Location-z 313 |
| |
| |
| |
| L | 145.15 | 313 | KNOLL | Location-z 313 |
| M | 145.15 | 313 | TSBD | Location-z 224 |
| N | 145.15 | 313 | TSBD | Location-z 313 |
| |
| |
| |
| O | 145.61 | 321 | TSBD | Location-z 313 |
| P | 145.61 | 321 | TSBD | Location- Tague |
| Q | 145.61 | 321 | TSBD | Location-z 224 |
| |
| |
| |
Question:
Why didn’t the data the BBN end up looking something like the first table. Where we don’t have contradictory correlations. Like a 1963 Dictabelt impulse pattern matches both a shot from the TSBD and from the Grassy Knoll. Where the shots end up hitting on or at least reasonably near the limousine?
Instead, we end up with a chart that contradicts itself, shows support for the same shot coming from the TSBD and the Grassy Knoll. And as far as “Target Locations” seems to find random correlations, and not correlations where the target location matches the limousine location at that time.
Why is that?
The obvious answer is bad data. And using a correlation coefficient threshold that is too low. Giving us random answers as to the location of the shooter and the location of the target.
The only part of the data is the location of the motorcycle. Well, not that good, because it does not match what is in the Hughes film and the Altgens photograph. But this can be explained by the hypotheses that the BBN only checked for matches where they anticipated where the motorcycle might be. Not all possible combinations but only the ones that seemed plausible. Due to a lack of time. So, if they found the first match 150 feet behind the limousine, they would look for the second 150 feet behind the limousine at the time of the second “shot”. So whatever correlation they discovered, it would match a motorcycle travelling 150 feet behind the limousine at around 11 mph.
Hence, the poor correlation of the location of the shooter, the poor correlation of the location of the target, but the good correlation of the location of the motorcycle. To me, this explanation makes sense.
-
********** Warning, this is not the real data, only what good data should look like **********
| |
| |
| |
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| |
| |
| |
| G | 139.27 | 205 | TSBD | Location-z 224 |
| |
| |
| |
| K | 140.32 | 224 | TSBD | Location-z 224 |
| |
| |
| |
| L | 145.15 | 313 | KNOLL | Location-z 313 |
| |
| |
| |
| O | 145.61 | 321 | TSBD | Location-z 313 |
| |
| |
| |
********** Here is the data the BBN actually got **********
| |
| |
| |
| Test | Beginning Time of | Zap. | Rifle | Target |
| ID | First impulse on | Frame | Location | Location |
| | Tape Segments (sec) | (Thomas) |
| |
| |
| |
| A | 136.20 |
| |
| |
| |
| B | 137.70 | 176 | TSBD | Location-z 155 |
| D | 137.70 | 176 | TSBD | Location-z 313 |
| E | 137.70 | 176 | KNOLL | Location- Tague |
| |
| |
| |
| G | 139.27 | 205 | TSBD | Location-z 313 |
| I | 139.27 | 205 | TSBD | Location-z 313 |
| J | 139.27 | 205 | KNOLL | Location-z 313 |
| |
| |
| |
| K | 140.32 | 224 | TSBD | Location-z 313 |
| |
| |
| |
| L | 145.15 | 313 | KNOLL | Location-z 313 |
| M | 145.15 | 313 | TSBD | Location-z 224 |
| N | 145.15 | 313 | TSBD | Location-z 313 |
| |
| |
| |
| O | 145.61 | 321 | TSBD | Location-z 313 |
| P | 145.61 | 321 | TSBD | Location- Tague |
| Q | 145.61 | 321 | TSBD | Location-z 224 |
| |
| |
| |
Question:
Why didn’t the data the BBN end up looking something like the first table. Where we don’t have contradictory correlations. Like a 1963 Dictabelt impulse pattern matches both a shot from the TSBD and from the Grassy Knoll. Where the shots end up hitting on or at least reasonably near the limousine?
Instead, we end up with a chart that contradicts itself, shows support for the same shot coming from the TSBD and the Grassy Knoll. And as far as “Target Locations” seems to find random correlations, and not correlations where the target location matches the limousine location at that time.
Why is that?
The obvious answer is bad data. And using a correlation coefficient threshold that is too low. Giving us random answers as to the location of the shooter and the location of the target.
The only part of the data is the location of the motorcycle. Well, not that good, because it does not match what is in the Hughes film and the Altgens photograph. But this can be explained by the hypotheses that the BBN only checked for matches where they anticipated where the motorcycle might be. Not all possible combinations but only the ones that seemed plausible. Due to a lack of time. So, if they found the first match 150 feet behind the limousine, they would look for the second 150 feet behind the limousine at the time of the second “shot”. So whatever correlation they discovered, it would match a motorcycle travelling 150 feet behind the limousine at around 11 mph.
Hence, the poor correlation of the location of the shooter, the poor correlation of the location of the target, but the good correlation of the location of the motorcycle. To me, this explanation makes sense.
This is both comical and pathetic. These questions are based on a mix of misreading and/or misrepresentation and omission.
Plus, I have already debunked several of the claims in his reply, but Mr. Elliott keeps repeating them anyway: To cite just one example, regarding his claim that "BBN only checked for matches where they anticipated where the motorcycle might be," this is utterly erroneous and is the exact opposite of what they did. It is beyond me how anyone could get on a public board and make such an abjectly false statement when the relevant materials make it clear that the BBN scientists did the exact opposite of what Mr. Elliott claims they did.
Be advised that Mr. Elliott is the same guy who spent weeks claiming that the 4-second impulse pattern was rejected only because it wasn't long enough, who could not tell the difference between Barger's testimony and the BBN report, who did not even understand the basic timeline of the HSCA acoustical analysis (i.e., the preliminary analysis vs. the later analysis done after the test firing), who did not even know when the HSCA said the first shot was fired, among other egregious errors. I don't mention these things to kick a wounded horse, but just to enable readers to understand Mr. Elliott's record of making erroneous statements.
The best way to answer Mr. Elliott's ball of confusion is not to spend numerous paragraphs unpacking his errors and omissions but to provide a clear explanation of the relevant facts. I will do so by quoting from Dr. G. Paul Chambers' chapter on the acoustical evidence in his book Head Shot: The Science Behind the JFK Assassination.
Dr. Chambers is a physicist and an internationally recognized expert in the field of shock physics. He has performed extensive high-speed photographic studies of high-velocity impacts and deformations of solids as well as computer modeling of shock wave and matter interactions. He has worked with NASA at NASA's Goddard Optics Branch. He has worked as a supervisory research physicist at the Energetic Materials and Detonation Science Department of the Naval Surface Warfare Center, and as a research physicist with the Condensed Matter and Radiation Sciences Division of the Naval Research Laboratory. The quote below appears in my article on the acoustical evidence, the same article that Mr. Elliott keeps pretending to be answering:
The HSCA commissioned the acoustics firm of Bolt, Beranek, & Newman (BBN) to perform a scientific analysis on the Dictabelt recording. This firm had previously successfully utilized acoustical analysis to determine the events that transpired during the Kent State shooting in 1970. Their acoustical analysis was later used as evidence presented to a grand jury to determine which national guardsman had fired first. BBN was also pointed by Judge John J. Sirica to serve on a panel of technical experts to analyze President Richard Nixon’s Watergate tapes.
Led by their chief scientist, Dr. James Barger, BBN converted the sounds on the tapes [the Channel 1 tape and the Channel 2 tape] to digitized waveforms. They then ran the waveforms through electronic filters to eliminate repetitive background noise like the sound of the motorcycle pistons firing. The firm then examined the processed waveforms for “sequences of impulses.” Their analysis indicated that there were six sequences of interest, spaced together within an eleven-second period recorded on channel 1, which could be consistent with the sounds of gunshots. . . .
Weiss and Aschkenasy reviewed Barger’s analysis and conclusions. They found that Barger’s analysis was valid and his conclusions supported by the evidence on the tape. They concurred with his recommendation to conduct live-fire tests in Dealey Plaza to determine the origin and direction of the gunshots, and they approved his plan for acoustical reconstruction. . . .
In Dealey Plaza, the sounds of gunshots would produce similar echoes. When recorded and captured on a specialized electronic device like an oscilloscope that converts sound patterns into pictures, these echoes appear as “acoustical waveforms” and appear as unique signatures of sound-producing events. In the case of a rifle shot in Dealey Plaza, the acoustical signatures would differ based on the origin, direction, and velocity of the shot, as well as the location of the recording microphone. The echo patterns would depend on the timing of sound reflections off building or other structures and obstructions in the plaza. . . .
A recording was made of the sounds received at each microphone during each test shot, making a total of 432 recordings of impulse sequences. . . . Each recorded impulse sequence was then compared with each of the six impulse patterns on the channel 1 Dictabelt recording to see the degree to which significant points in each impulse pattern matched. . . .
The time of the arrival of the impulses, or echoes, in each sequence of impulses was the characteristic being compared, not the shape, amplitude, or any other characteristic of the impulses or sequences. . . .
When the BBN team performed their analysis of the acoustical waveforms, they
found something extraordinary. When they compared the impulse sequences
from the acoustical reconstruction to the sequences on the original Dictabelt
recording, they found a number of significant matches. When the locations of the
microphones that recorded matches in the reconstruction were plotted on a
graph of time versus distance, it was found that the location of the microphones
that recorded matches were clustered around a line on the graph that was
consistent with the known speed of the motorcade (11 mph). . . .
Of the thirty-six microphones placed along the motorcade route, the one that recorded the sequence of impulses that matched the third impulse on the 1963 dispatch tape [the dictabelt tape] was farther along the route than the one that recorded the impulses that matched the second impulse on the dispatch tape. The locations of the microphones were consistent with the distance a motorcycle traveling at about 11 mph would cover in the elapsed time between impulses on the dispatch tape. . . . Applying a statistical formula, Barger estimated that since the microphones clustered around a line representing the speed of the motorcade, there was a 99 percent probability that the Dallas police dispatch tape did, in fact, contain impulses transmitted by a microphone in the motorcade in Dealey Plaza during the assassination. . . .
Weiss and Aschkenasy, specialists in sonar applications . . . examined Dealey Plaza carefully to determine which structures were most likely to have caused the echoes recorded by the microphone in the acoustical reconstruction that had exhibited a match to the shot from the grassy knoll. They verified and refined their identifications of echo-producing structures by examining the results of the 1978 reconstruction [the test firing in Dealey Plaza]. This approach allowed them to look for matches in the data with a 1 ms [millisecond] correlation. . . . Matches at this level of temporal precision substantially reduced the possibility that a
match could occur as a result of random noise.
In Dealey Plaza, echoes from gunshot test patterns arrive in two discrete [different] clusters, differing in time by about 190 ms. Echoes originating from structures along Elm Street arrive within 85 ms, while echoes from structures farther back on Houston Street arrive in the last 95 ms of a typical 370-msduration test pattern. In addition, a “muzzle blast” is usually prominent at the beginning of a gunshot acoustical pattern, while an N-wave (a shock wave traveling faster than the speed of sound due to the rifle bullet exceeding the sound barrier) arrives prior to the muzzle blast. The waveform identified as the grassy knoll shot is shown in figure 13. The presence of an N-wave in this waveform was consistent with the acoustical signature of a supersonic rifle bullet. . . .
Weiss and Aschkenasy were able to incorporate the movement of the motorcycle in their analytical model. For instance, over the time period of the 370-ms gunshot acoustical pattern recording, the motorcycle would have moved about five feet. Therefore, corrections had to be made to account for a moving microphone during the actual 1963 events. They also took into account muting and distortion of the acoustical signature due to the windshield of the motorcycle. When they considered this in their analysis, they found that the earlier shots determined by BBN to be from the Texas School Book Depository showed this distortion, while the acoustical sequence that matched the test shot from the grassy knoll did not exhibit this effect.
This is precisely the result expected for a microphone mounted on a motorcycle moving in Kennedy’s motorcade along Houston Street facing the Depository, where the sound of the shot from this location would pass through the windshield, but moving sideways to the direction of the grassy knoll so that a shot from this location would not need to pass through the windshield to reach the microphone. This lent further credence to the validity of their analysis. (Chambers 96-102)
Here is my article, the one that Mr. Elliott keeps pretending he's answering:
https://miketgriffith.com/files/hscaacous.pdf
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This is both comical and pathetic. These questions are based on a mix of misreading and/or misrepresentation and omission.
Plus, I have already debunked several of the claims in his reply, but Mr. Elliott keeps repeating them anyway: To cite just one example, regarding his claim that "BBN only checked for matches where they anticipated where the motorcycle might be," this is utterly erroneous and is the exact opposite of what they did. It is beyond me how anyone could get on a public board and make such an abjectly false statement when the relevant materials make it clear that the BBN scientists did the exact opposite of what Mr. Elliott claims they did.
Be advised that Mr. Elliott is the same guy who spent weeks claiming that the 4-second impulse pattern was rejected only because it wasn't long enough, who could not tell the difference between Barger's testimony and the BBN report, who did not even understand the basic timeline of the HSCA acoustical analysis (i.e., the preliminary analysis vs. the later analysis done after the test firing), who did not even know when the HSCA said the first shot was fired, among other egregious errors. I don't mention these things to kick a wounded horse, but just to enable readers to understand Mr. Elliott's record of making erroneous statements.
The best way to answer Mr. Elliott's ball of confusion is not to spend numerous paragraphs unpacking his errors and omissions but to provide a clear explanation of the relevant facts. I will do so by quoting from Dr. G. Paul Chambers' chapter on the acoustical evidence in his book Head Shot: The Science Behind the JFK Assassination.
Dr. Chambers is a physicist and an internationally recognized expert in the field of shock physics. He has performed extensive high-speed photographic studies of high-velocity impacts and deformations of solids as well as computer modeling of shock wave and matter interactions. He has worked with NASA at NASA's Goddard Optics Branch. He has worked as a supervisory research physicist at the Energetic Materials and Detonation Science Department of the Naval Surface Warfare Center, and as a research physicist with the Condensed Matter and Radiation Sciences Division of the Naval Research Laboratory. The quote below appears in my article on the acoustical evidence, the same article that Mr. Elliott keeps pretending to be answering:
Here is my article, the one that Mr. Elliott keeps pretending he's answering:
https://miketgriffith.com/files/hscaacous.pdf
Mr. Griffith is playing the same trick he often plays. He claims an issue has already been dealt with and provides a link to a long article. And implies that the answer is to be found somewhere in this article.
It would be easy for him to cut and paste the relevant paragraph if, it existed. As an example, I will cut and paste a random paragraph from his article to show how easy this is:
Random Paragraph:
Led by their chief scientist, Dr. James Barger, BBN converted the sounds on the
tapes [the Channel 1 tape and the Channel 2 tape] to digitized waveforms. They
then ran the waveforms through electronic filters to eliminate repetitive
background noise like the sound of the motorcycle pistons firing. The firm then
examined the processed waveforms for “sequences of impulses.” Their analysis
indicated that there were six sequences of interest, spaced together within an
eleven-second period recorded on channel 1, which could be consistent with the
sounds of gunshots. . . .
So as far as the two claims I have made, he has not really provided any quotes from Mr. Barger that either is false. These claims are:
1. There are two impulse pattern sequences recorded, just during the 5.5-minute period that the transmission key is stuck. One is 10 seconds long, the other 4. So, it appears the 10-second-long sequence is not unique. Since both were not caused by gunfire, perhaps neither were.
Perhaps if this second sequence was analyzed, they would have found correspondence with some impulse waves from their 1978 tests.
The only quotes I can find from Dr. Barger, about why the 4-second sequence was not investigated further were:
a. The sequence was too short, since the Zapruder film seemed to show the shooting lasted at least 5 seconds.
b. He claims it must have been created by someone else trying to transmit over Channel 1. But does not provide any technical reasons why he believes this, like the amplitude of the waves was too large or too small. For all I know, this is speculation on Dr. Barger’s part.
2. I believe it is likely that BBN did not systematically check all 2,592 combinations of the 432 waveforms, created in the 1978 tests, with the 6 waveforms of interest, recorded on the 1963 Dictabelt. I believe this was not done because of the lack of time, only 10 days to make the measurements and to do the calculations with calculators where all the numbers would have to be manually entered.
Instead, I speculate that after they thought they found one shot, they used this information, combined with the assumption that the motorcycle maintained a roughly 11 mph speed to tell them where to go look for other matches. If this was done, any correlation they found would match the scenario of a motorcycle moving at 11 mph. This would explain why the location of the motorcycle gets consistent results, which is what you want. While still getting random results for the location of the shooter and the area of Elm Street the bullet struck.
Again, this is speculation on my part but reasonable speculation. It provides an explanation as to why the data for the location of the motorcycle is good, while the data for the location of the shooter and where the bullet struck is so bad.
And Mr. Griffith, for all his bluster, has not provided us with a quote from Dr. Barger where he claims they did indeed conduct a systematic check of all possible 2,592 combinations in the time period of 10 days, from when the shooting tests were conducted, to when he called the HSCA to report that they had found 15 correlations.
Now, I can find claims on the internet that Dr. Barger had completed these 2,592 comparisons. But neither I, nor apparently Mr. Griffith, can find a where Dr. Barger claims that all these 2,592 comparisons were actually done.
Again, why should my speculation:
that the BBN did not conduct a thorough systematic search through all 2,592 combinations, due to a lack of time
be considered more likely than Mr. Griffith’s speculation:
that that BBN did conduct a thorough systematic search through all 2,592 combination, despite the time pressure
Because my theory explains why the BBN data is so bad at getting results that don’t contradict themselves as to the location of the shooter and where the bullet struck, while giving consistent results on the location of the motorcycle. And Mr. Griffith’s theory, does not.
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One aspect of the case that CTers make for the Acoustic evidence, is a strong tendency to emphasis the positive and to skip over the negative, as far as the correlations the BBN found. This is most obvious in the maps of Dealey Plaza to show the information about the acoustic tests.
Below is a typical map used by CTers:
https://www.maryferrell.org/wiki/images/6/60/Pict_essay_acousticshistory_AcousticMap_lrg.jpg (https://www.maryferrell.org/wiki/images/6/60/Pict_essay_acousticshistory_AcousticMap_lrg.jpg)
Very prominent are the circles that show the estimate of the motorcycle positions. This is, by far, the most positive aspect of the BBN Data shown in F-367.
They often do not show the location of the “Target”, the area where the bullet struck. Or, if shown, is shown in very small print that is difficult, often impossible, to read. This hides how wildly F-367 is off on these estimates. It appears that right from the beginning, BBN was, at least subconsciously, hiding this flaw. In F-367, under the “Target Location” column, they could have put “z-155”, “z-224”, “z-333” or “Tague” to clearly show where the acoustic evidence indicated where the bullet struck. Instead, they used “Target 1, 2, 3, 4” so it was not as clear how wildly off these estimates were.
The location of the shooter was less easy to conceal. Not referring to the target locations as “TSBD” and “Grassy Knoll” but as “Shooter 1” and “Shooter 2” would have obscured a major point they were trying to make. A shot from the grassy knoll was discovered.
Even the motorcycle positions shown on the map are a little dishonest. They show the locations of the motorcycle, the green circles, based on their evidence, after they tossed out the “false alarms”. But much of the evidence does not match this.
Particularly for the second shot. While a couple of the table entries of F-367 match the second circle, one of them matches the fifth circle, about 110 feet up the road. Another is about 25 feet up the road. That is why I think this second shot was the first one they searched for, giving us a wide stretch of found correlations, before the search focus became so much narrower for the other shots.
Also, the locations for the motorcycle for the fourth shot are not too good. While one of the correlations is in the center of the fourth green circles, the other two are 25 to 30 feet further up the road.
And the location for the fifth motorcycle for the fifth shot are also off. Again, one of the correlations is in the center of the fifth greet circle, but the other two are further up the road, one by 20 feet.
So, while Mr. Griffith, and even I, have spoken of the good correlation of the data with the motorcycle position consistent with the motorcycle trailing behind by 150 feet at 11 mph, this “good correlation” is greatly exaggerated. It is based on the tossing out a lot of correlations that are deemed “false alarms”.
But problems with the motorcycle estimates are difficult to see, because the positions of the microphones are hard to see, particularly for the second array, 2 ( 1 ) through 2 ( 12 ).
So, there are clear signs of the BBN and its supporters trying to emphasis the “good” correlation of the motorcycle position. I doubt the BBN would have overlooked any chance to bolster this. So, if a through examination of all 2,592 combinations had been made, Dr. Barger would have certainly driven this point home. To show the good estimates of the motorcycle position was valid and not based on a partial sampling of the data. The lack of such clear statements from Dr. Barger is an indicator to me, that the search of the matches was not a through search of all the data, all the 2,592, but was a partial sampling of the data. So that the search of the data for the “forward” microphones, was not done for the early shots, since no valid shot could be found there. And the search of the data for the “rearward” microphones, was not done for the later shots, since no valid shot could be found there. And time constraints may have made this search very focused for each shot except the first they looked for. Hence, the lack of so many wild estimates for the location of the motorcycle, as we get for the shooter location and the target location.
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That's around the windscreen. Our circus midget has no effing clue what he's talking about.
"we know from science" -- LOL
Oh . . . boy . . . . LOL indeed. It's actually both through and around, and sometimes authors pick one or the other. You'll notice that Dr. Chambers chose to say "through": "would pass through the windshield." Sound passes both through and goes around an object. That's why you can hear sounds from outside your car even if you have your windows rolled up. That's why you can hear sounds from outside your house even if you have all of your windows closed, or even if you're in a room with no windows. Rather than say "through and around" some authors just pick one or the other.
Anyway, moving on from Otto Beck's latest gaffe, I'd like to discuss a correlation that I have not discussed yet. The HSCA acoustical scientists noticed early on that about 3 seconds before the first gunshot on the police tape, the motorcycle's engine noise drops substantially. At that point in time, they did not understand the significance of this. Only later, after they did the test firing and then looked at the sound impulse data from the microphones, did they understand the importance of this. They realized that the drop in motorcycle noise corresponded to the time when the motorcycle would have slowed down to turn onto Houston Street! Dr. Barger:
Now, if you recall the first thing we noticed on the tape was that there was a diminution of the sound due to the motorcycle 3 seconds prior to the first impulsive pattern that we originally suspected could be caused by gunfire.
There was no obvious explanation for that, until one sees that at that time the motorcycle was just beginning a 110° turn, and on the inside track apparently, and he would therefore have to slow down to execute the turn. (2 HSCA 68)
And I see Mr. Elliott has apparently decided to stop trying to deal directly with the windshield-distortion correlations and is once again demanding answers to his irrelevant, error-based questions. Just to recap, the three TSBD shots contain windshield distortion because the patrolman's microphone was in a position where the gunshot sound waves would have encountered his windshield before reaching the microphone. But, for the grassy knoll shot, where the motorcycle was in a position where the windshield did not intervene between the gunshot sound waves and the microphone, there is no windshield distortion. Think about the number of factors that would have to come together to make these correlations possible. Here are just some of them:
* The motorcycle would have had to be in the correction positions on Houston Street and at the very beginning of Elm Street after turning off Houston Street for the windshield to be able to cause any distortion.
* The motorcycle would have had to be at point on Elm Street where the grassy knoll gunshot sound waves could have reached the microphone without being affected by the windshield in any measurable way.
* To get to the correct locations on Houston and Elm Streets in the first place, the motorcycle would have had to be moving at an average speed almost identical to that of the motorcade.
* The motorcycle would have had to be far enough back in the motorcade to begin with in order to reach the required locations at the correct average speed.
Finally, here is an informative, instructive interview with Dr. Thomas on the acoustical evidence. The audio is very clear. The interview runs 34 minutes:
https://www.maryferrell.org/pages/Unredacted_-_Episode_4.html
Here's the transcript of the interview:
https://www.maryferrell.org/pages/Unredacted_-_Episode_4_-_Transcript.html
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REX-So, I want to fast forward back to your work, I mean, that HSCA acoustics evidence was reportedly debunked, first by a FBI report, then by the Ramsey Panel appointed by the National Academy of Sciences in the early eighties.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Thomas -On the recording itself, what you hear on the police recording - for about five and a half minutes - you can hear the sound of a motorcycle motor. So what had happened, on the police channel - which was used for normal communications, for five and a half minutes you're essentially jammed, by - somewhere in Dallas - a microphone on a motorcycle cop's radio has jammed open, so you hear the sound of a motorcycle motor.
You also hear - on the recording - you also hear sirens. And this is the clue that led people to think that this was the assassination - that this was the motorcycle that was with the motorcade at the time of the assassination because the one event that was happening, the one emergency that would require sirens was the fact that the President's motorcade was on its way to Parkland Hospital immediately after the assassination.
When I first heard the police tapes...I came to the conclusion that the "stuck microphone" was a deliberate act to confuse the activities in Dealey Plaza. I still think so.
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And I see Mr. Elliott has apparently decided to stop trying to deal directly with the windshield-distortion correlations and is once again demanding answers to his irrelevant, error-based questions. Just to recap, the three TSBD shots contain windshield distortion because the patrolman's microphone was in a position where the gunshot sound waves would have encountered his windshield before reaching the microphone. But, for the grassy knoll shot, where the motorcycle was in a position where the windshield did not intervene between the gunshot sound waves and the microphone, there is no windshield distortion. Think about the number of factors that would have to come together to make these correlations possible. Here are just some of them:
* The motorcycle would have had to be in the correction positions on Houston Street and at the very beginning of Elm Street after turning off Houston Street for the windshield to be able to cause any distortion.
* The motorcycle would have had to be at point on Elm Street where the grassy knoll gunshot sound waves could have reached the microphone without being affected by the windshield in any measurable way.
* To get to the correct locations on Houston and Elm Streets in the first place, the motorcycle would have had to be moving at an average speed almost identical to that of the motorcade.
* The motorcycle would have had to be far enough back in the motorcade to begin with in order to reach the required locations at the correct average speed.
You bring up so many low-quality arguments that I don’t bother to respond to most of them.
Well, I could deal with this windshield-distortion issue the same way Dr. Barger deals with these sorts of problems. The windshield-distortion correlations should be considered “false alarms”, that is “false positives”, so I don’t have to account for them.
The fact that the BBN found correlations, for 3 of the 5 shots, for both the TSBD and the Grassy Knoll, outweigh any consideration of windshield-distortion. What is windshield-distortion compared to misestimating the position of the shooter, with some of the correlations by over 200 feet.
But now, on to handling the windshield-distortion issue. You claim that windshield-distortion did occur with the first three shots from the TSBD (I assume 137.70, 139.27 and 140.32) but did not occur with the Grassy Knoll shot at 145.15. Now, the question I have, is:
Who determined this?
I don’t recall reading where Dr. Barger or any report from BBN discussed this windshield-distortion in their reports to the HSCA.
And it couldn’t have been Weiss and Aschkenasy because, as I understand it, they only looked at the grassy knoll shot of 145.15. They did not look at the earlier shots at all, because of a lack of time. So, they might have said there was no windshield-distortion for the grassy knoll shot, but they couldn’t have had an opinion on the 3 earlier shots.
So, I would guess it would be our Insect expert, Dr. Thomas, who determined, from his analysis, that the first three shots had no windshield-distortion, but the grassy knoll shot did.
Question:
Is this right? The determination of the first 3 shots had windshield-distortion, but the grassy knoll shot did not, was not made by Dr. Barger. Was not made by BBN. Was not made by Weiss and Aschkenasy, but was instead made by Dr. Thomas?
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When I first heard the police tapes...I came to the conclusion that the "stuck microphone" was a deliberate act to confuse the activities in Dealey Plaza. I still think so.
How exactly would a stuck microphone confuse the activities in Dealey Plaza?
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And I see Mr. Elliott has apparently decided to stop trying to deal directly with the windshield-distortion correlations and is once again demanding answers to his irrelevant, error-based questions. Just to recap, the three TSBD shots contain windshield distortion because the patrolman's microphone was in a position where the gunshot sound waves would have encountered his windshield before reaching the microphone. But, for the grassy knoll shot, where the motorcycle was in a position where the windshield did not intervene between the gunshot sound waves and the microphone, there is no windshield distortion. Think about the number of factors that would have to come together to make these correlations possible. Here are just some of them:
* The motorcycle would have had to be in the correction positions on Houston Street and at the very beginning of Elm Street after turning off Houston Street for the windshield to be able to cause any distortion.
* The motorcycle would have had to be at point on Elm Street where the grassy knoll gunshot sound waves could have reached the microphone without being affected by the windshield in any measurable way.
* To get to the correct locations on Houston and Elm Streets in the first place, the motorcycle would have had to be moving at an average speed almost identical to that of the motorcade.
* The motorcycle would have had to be far enough back in the motorcade to begin with in order to reach the required locations at the correct average speed.
I have one more point to make about this grassy-knoll-shot / no-windshield-distortion issue.
Now, the grassy knoll shot was the fourth of the five shots (if one accepts the 140.32 as a shot).
The following map shows where the motorcycle was for this shot, the fourth green circle.
(https://www.maryferrell.org/wiki/images/6/60/Pict_essay_acousticshistory_AcousticMap_lrg.jpg)
Question:
Shouldn’t we expect to have windshield-distortion from the grassy knoll for this shot?
Either from the “Badgeman” position, or the “Grassy Knoll Gunsmoke” position, either position is almost directly ahead of the motorcycle, while in this fourth circle.
True, from the limousine’s point of view, it is up far enough Elm Street for the Grassy Knoll to be off to the side. But the BBN did not say the gunshots were recorded from the limousine. They said the gunshots were recorded from the motorcycle trailing behind by 150 feet.
Is this an issue you forgot about, the recording made not from the limousine but from the motorcycle, so the grassy knoll would not be off to the side?
It will be interesting to see if it is Mr. Griffith who “decides to stop trying to deal directly with the windshield-distortion correlations” issue.
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From the quote Mr. Griffith provided:
Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone.11 On shot four, Weiss and Aschkenasy found no such distortion.(55) The analysts' ability to predict the effect of the windshield on the impulses found on the dispatch tape, and having their predictions confirmed by the tape, indicated further that the microphone was mounted on a motorcycle in Dealey Plaza and that it had transmitted the sounds of the shots fired during the assassination.
It appears to me, that the source of this “No Windshield-Distortion” for the grassy knoll shot is:
Jason A. Perdue
In his book:
People in High Places – An Investigation of the Assassination of President John F. Kennedy
https://www.amazon.com/People-High-Places-Paperback-2/dp/1387356488 (https://www.amazon.com/People-High-Places-Paperback-2/dp/1387356488)
This book has zero customer reviews. It appears not too many people have read it, besides Mr. Griffith.
So, Mr. Griffith might consider giving this book a one-star customer rating.
By the way, this book is available at Amazon for $ 39.50 but you might be able to get it cheaper from Mt. Griffith.
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You bring up so many low-quality arguments that I don’t bother to respond to most of them.
LOL! "Low-quality arguments"?! You mean like when you made the comical claim that the HSCA acoustical experts found N-waves "scattered throughout" the dictabelt tape? You mean like when you made erroneous claims about what was and was not done in the preliminary analysis because you clearly did not know the basic timeline of the HSCA acoustical analysis, did not know what was done in the preliminary analysis vs. what was done later? You mean like when you gave the wrong time that the HSCA acoustical experts gave for when the first shot occurred (because you were relying on Bowles' bogus transcript)? You mean like when you spent weeks making the false claim that the 4-second impulse pattern was rejected only because it was too short, when in fact it was rejected because it failed two--not just one--of the initial screening tests and showed no N-wave or muzzle-blast patterns? You mean like when you somehow, someway mistook Barger's testimony for the BBN report? You mean like when you initially pretended that windshield distortion is not a known phenomenon in acoustical science? And on and on I could go.
You have proved yourself to be a total joke on the acoustical evidence. But, every time you are caught in an egregious gaffe, you brush it off and post more endlessly long replies based on your misreading and/or mischaracterization of the HSCA materials. You never quote any scholars. You run to pro-WC propaganda sites and often copy and paste their bogus arguments but present them as your own.
My "low-quality arguments" are based on the research done by the only six acoustical experts to ever analyze the dictabelt tape (Barger, Robinson, Schmidt, Wolf, Weiss, Aschkenasy), by an internationally recognized expert in shock physics (Chambers), by a scholar with a PhD in mathematics from MIT (Scheim), by a research scientist whose work on the acoustical evidence has been published in a peer-reviewed criminal science journal (Thomas), by a scientist with a degree in mathematics and another degree in applied mathematics (Charnin), by a physicist who's authored books on physics and astronomy (Stahl), among other scholars. And I have quoted from most of these scientists' analyses.
Well, I could deal with this windshield-distortion issue the same way Dr. Barger deals with these sorts of problems. The windshield-distortion correlations should be considered “false alarms”, that is “false positives”, so I don’t have to account for them.
This is too ignorant, too comical to waste time answering. But, I will duly add this claim to your ever-growing list of howlers.
The fact that the BBN found correlations, for 3 of the 5 shots, for both the TSBD and the Grassy Knoll, outweigh any consideration of windshield-distortion. What is windshield-distortion compared to misestimating the position of the shooter, with some of the correlations by over 200 feet.
This is more raw, comical ignorance. 200 feet?! This goofiness is based on your continued misreading of the HSCA materials. You realize that nearly instantaneous echoes caused some of the individual matches but that these were recognized as false positives by time-distance analysis of the motorcycle's movements, right? You realize that any rational doubt about the grassy-knoll-shot matches was removed by the WA sonar analysis, right?
But now, on to handling the windshield-distortion issue. You claim that windshield-distortion did occur with the first three shots from the TSBD (I assume 137.70, 139.27 and 140.32) but did not occur with the Grassy Knoll shot at 145.15. Now, the question I have, is:
Who determined this?
I don’t recall reading where Dr. Barger or any report from BBN discussed this windshield-distortion in their reports to the HSCA.
And it couldn’t have been Weiss and Aschkenasy because, as I understand it, they only looked at the grassy knoll shot of 145.15. They did not look at the earlier shots at all, because of a lack of time. So, they might have said there was no windshield-distortion for the grassy knoll shot, but they couldn’t have had an opinion on the 3 earlier shots.
So, I would guess it would be our Insect expert, Dr. Thomas, who determined, from his analysis, that the first three shots had no windshield-distortion, but the grassy knoll shot did.
Question:
Is this right? The determination of the first 3 shots had windshield-distortion, but the grassy knoll shot did not, was not made by Dr. Barger. Was not made by BBN. Was not made by Weiss and Aschkenasy, but was instead made by Dr. Thomas?
It appears to me, that the source of this “No Windshield-Distortion” for the grassy knoll shot is: Jason A. Perdue
In his book:
People in High Places – An Investigation of the Assassination of President John F. Kennedy
So "it couldn’t have been Weiss and Aschkenasy," hey? Weiss and Aschkenasy could not have discussed the windshield-distortion evidence, hey? This gaffe proves you still have not bothered to read their testimony. Dr. Weiss talked about windshield distortion extensively in his testimony. He explained how windshield distortion accounted for some of the patterns seen in the graphical representation (oscillogram/spectrogram) of the dictabelt gunshot impulse patterns:
The second thing is, if you look at these patterns in somewhat more expanded detail than perhaps is visible here, you will see in the case of the muzzle blast there is a very sharp, short, initial, positive, upward going spike or peak, then it goes strongly down, and then it comes up again, and so on.
Now, in fact, as recorded through a high-fidelity system and an open microphone, it really does this, it is very sharply upward first, then it goes down and so on.
Well, something must have happened to this upward, strong one to make it seem much smaller. It now is just a little bitty one over here. It goes down, and now it comes up afterwards, and does that sort of thing. And we considered why that is so, and thought that it is probable that if this is a microphone on the motorcycle, and the motorcycle, in fact, is over here in Dealey Plaza, facing in this direction, and if there is a rifle over here, that the windshield of the motorcycle is sort of between the sound that comes directly at it from the muzzle blast and the microphone, so the windshield is screening the microphone to some degree.
Well, the effect of that can be predicted. But to confirm our understanding of this, we arranged with the New York City Police Department to perform some experiments at their shooting range in the Bronx. We went out there, and they trotted out an old Harley-Davidson motorcycle and put a transmitter on it, vintage 1963 or 1964, and an old microphone pretty much the same kind as was used by the Dallas Police Department, and we performed some experiments with people firing rifles at various locations, sometimes with the motorcycle facing the shooter, sometimes with the motorcycle crosswise to the shooter. At the same time we made recordings using high fidelity equipment of the sounds of the shots.
Now there were two kinds of recordings made. The first, as I say, was high fidelity equipment, good microphone, good recorder on the spot. The second was through the microphone which was on the motorbike, which was a microphone of the type used in Dallas, through the transmitter, and recorded downtown at the police communications laboratory. And we compared the results of these two recordings, and what we found was exactly what we had thought we would find, that is, that in the case of the high fidelity recording, we got that kind of big, first spike upward and downward, and so on. In the case of the recording made through the police microphone, that first spike was greatly attenuated [weakened] and it went negative and came back up and so on. This was true, however, only in the case where the motorcycle was facing the rifle.
When the motorcycle was crosswise to the rifle, the recording made by the police microphone fairly closely matched, looks, looked pretty much like, with some distortions, but looked pretty much like the recording made using the high fidelity equipment. So it was essentially confirmed that the windshield really does have this effect on reducing the strength of that initial, very sharp spike received, and, of course, this is what we have over here. It is consistent with the assumption that this is a microphone behind the windshield facing a rifle. (5 HSCA 581-582)
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And I see Mr. Elliott has apparently decided to stop trying to deal directly with the windshield-distortion correlations and is once again demanding answers to his irrelevant, error-based questions. Just to recap, the three TSBD shots contain windshield distortion because the patrolman's microphone was in a position where the gunshot sound waves would have encountered his windshield before reaching the microphone. But, for the grassy knoll shot, where the motorcycle was in a position where the windshield did not intervene between the gunshot sound waves and the microphone, there is no windshield distortion. Think about the number of factors that would have to come together to make these correlations possible. Here are just some of them:
It now appears that it is Mr. Griffith who is running away from the windshield-distortion correlation issue. So, let me repeat the point I made yesterday.
The grassy knoll shot was the fourth of the five shots (if one accepts the 140.32 as a shot).
The following map shows where the motorcycle was for this shot, the fourth green circle.
(https://www.maryferrell.org/wiki/images/6/60/Pict_essay_acousticshistory_AcousticMap_lrg.jpg)
Questions:
1. Shouldn’t we expect to have windshield-distortion from the grassy knoll for this shot?
2. What do you mean that the windshield would not intervene with the grassy knoll shot?
Of course, it would have. The motorcycle would have been almost pointed directly at the grassy knoll, while in the fourth circle.
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Mr. Elliott's surprising claim that the windshield-distortion correlations originated with Jason Perdue's book People in High Places deserves further comment. Anyone who has read the HSCA materials knows that not only did Weiss and Aschkenasy note these correlations in their testimony and in their report, but that the HSCA report noted them as well.
But now, on to handling the windshield-distortion issue. You claim that windshield-distortion did occur with the first three shots from the TSBD (I assume 137.70, 139.27 and 140.32) but did not occur with the Grassy Knoll shot at 145.15. Now, the question I have, is:
Who determined this?
I don’t recall reading where Dr. Barger or any report from BBN discussed this windshield-distortion in their reports to the HSCA.
And it couldn’t have been Weiss and Aschkenasy because, as I understand it, they only looked at the grassy knoll shot of 145.15. They did not look at the earlier shots at all, because of a lack of time. So, they might have said there was no windshield-distortion for the grassy knoll shot, but they couldn’t have had an opinion on the 3 earlier shots.
So, I would guess it would be our Insect expert, Dr. Thomas, who determined, from his analysis, that the first three shots had no windshield-distortion, but the grassy knoll shot did.
Question:
Is this right? The determination of the first 3 shots had windshield-distortion, but the grassy knoll shot did not, was not made by Dr. Barger. Was not made by BBN. Was not made by Weiss and Aschkenasy, but was instead made by Dr. Thomas?
It appears to me, that the source of this “No Windshield-Distortion” for the grassy knoll shot is: Jason A. Perdue
In his book:
People in High Places – An Investigation of the Assassination of President John F. Kennedy
I had never heard of Perdue's book until I read this reply. I tracked down an online copy of the book (2nd edition). Perdue does not say the grassy knoll shot had no windshield distortion. He correctly observes that the final shot was the one that was found to have no windshield distortion, not the grassy knoll shot (pp. 69-70).
Coincidentally, just before I looked up Perdue's book, I realized that the fourth shot was the no-windshield-distortion shot after I went back and re-read the HSCA report's section on the acoustical evidence. I have revised my article on the acoustical evidence accordingly.
When you look at the position of the motorcycle for the third shot and the fourth shot, it makes perfect sense that the fourth shot does not contain any windshield distortion. For the grassy knoll shot, as with the two previous shots, the windshield was still between the rifle and the microphone, but this was not the case for the fourth shot. This is an astonishing coincidence if the dictabelt tape does not contain JFK assassination gunfire.
Several folks who have read Weiss's testimony on this subject have inferred that he was implying that the grassy knoll shot was the shot with no windshield distortion. This is how I had read his testimony as well. This is even how Dr. Chambers read his testimony. With tongue in cheek, I blame Dr. Weiss for not specifying by number the shots with windshield distortion ala the HSCA report! The HSCA report sets the matter straight:
Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone. On shot four, Weiss and Aschkenasy found no such distortion.(55) The analysts' ability to predict the effect of the windshield on the impulses found on the dispatch tape, and having their predictions confirmed by the tape, indicated further that the microphone was mounted on a motorcycle in Dealey Plaza and that it had transmitted the sounds of the shots fired during the assassination. (HSCA report, pp. 74-75)
So, now that we have cleared up the confusion about which shots were and were not found to contain windshield distortion, we see that the windshield-distortion correlations are powerful, convincing evidence that the police tape contains at least four gunshots. Again, if these correlations are all just a coincidence, they are an astounding, astronomically improbable coincidence. When you think about the number of factors that would have to align by pure chance to make it theoretically possible for these correlations to be mere coincidence, you realize that the only rational conclusion is that they are not a coincidence but are hard evidence that the HSCA acoustical experts were correct.
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Mr. Elliott's surprising claim that the windshield-distortion correlations originated with Jason Perdue's book People in High Places deserves further comment. Anyone who has read the HSCA materials knows that not only did Weiss and Aschkenasy note these correlations in their testimony and in their report, but that the HSCA report noted them as well.
I had never heard of Perdue's book until I read this reply. I tracked down an online copy of the book (2nd edition). Perdue does not say the grassy knoll shot had no windshield distortion. He correctly observes that the final shot was the one that was found to have no windshield distortion, not the grassy knoll shot (pp. 69-70).
Coincidentally, just before I looked up Perdue's book, I realized that the fourth shot was the no-windshield-distortion shot after I went back and re-read the HSCA report's section on the acoustical evidence. I have revised my article on the acoustical evidence accordingly.
When you look at the position of the motorcycle for the third shot and the fourth shot, it makes perfect sense that the fourth shot does not contain any windshield distortion. For the grassy knoll shot, as with the two previous shots, the windshield was still between the rifle and the microphone, but this was not the case for the fourth shot. This is an astonishing coincidence if the dictabelt tape does not contain JFK assassination gunfire.
Several folks who have read Weiss's testimony on this subject have inferred that he was implying that the grassy knoll shot was the shot with no windshield distortion. This is how I had read his testimony as well. This is even how Dr. Chambers read his testimony. With tongue in cheek, I blame Dr. Weiss for not specifying by number the shots with windshield distortion ala the HSCA report! The HSCA report sets the matter straight:
So, now that we have cleared up the confusion about which shots were and were not found to contain windshield distortion, we see that the windshield-distortion correlations are powerful, convincing evidence that the police tape contains at least four gunshots. Again, if these correlations are all just a coincidence, they are an astounding, astronomically improbable coincidence. When you think about the number of factors that would have to align by pure chance to make it theoretically possible for these correlations to be mere coincidence, you realize that the only rational conclusion is that they are not a coincidence but are hard evidence that the HSCA acoustical experts were correct.
I did make an error. I found a phrase you quoted from an unnamed source, did a google search, and found it in a book published by Jason Perdue’s book, “People in High Places”. So, you were not quoting Jason Perdue. You were both quoting an HSCA report. But this was not clear from your original post.
Coincidentally, just before I looked up Perdue's book, I realized that the fourth shot was the no-windshield-distortion shot after I went back and re-read the HSCA report's section on the acoustical evidence. I have revised my article on the acoustical evidence accordingly.
https://www.archives.gov/research/jfk/select-committee-report/part-1b.html
And here is the paragraph from Weiss and Aschkenasy. It straddles Page 73 and 74:
Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone.11 On shot four, Weiss and Aschkenasy found no such distortion. (55) The analysts' ability to predict the effect of the windshield on the impulses found on the dispatch tape, and having their predictions confirmed by the tape, indicated further that the microphone was mounted on a motorcycle in Dealey Plaza and that it had transmitted the sounds of the shots fired during the assassination.
So, yes, the shot that that Weiss and Aschkenasy found no windshield distortion was the four BBN shot, or the fifth Thomas shot, the last shot. And it was determined to be from the TSBD.
I’m still a little perplexed about this though. Yes, the windshield would not be in the way of this last shot. But Officer McLain’s torso would have been squarely in the way. So, I am not too impressed with Weiss and Aschkenasy finding no distortion in this last impulse, as they had found in the first three. Why wouldn’t Officer McLain’s torso cause distortions, when the sound waves were forced to bend around his torso, just as the wound waves had to bend around the windshield from the first three shots.
Several folks who have read Weiss's testimony on this subject have inferred that he was implying that the grassy knoll shot was the shot with no windshield distortion. This is how I had read his testimony as well. This is even how Dr. Chambers read his testimony. With tongue in cheek, I blame Dr. Weiss for not specifying by number the shots with windshield distortion ala the HSCA report! The HSCA report sets the matter straight:
How could Dr. Chambers be ignorant of all this?
How could he not know that for the “grassy knoll” shot, the grassy knoll would be almost directly ahead of the motorcycle?
How could Dr. Chambers have concluded that the Weiss and Aschkenasy found no windshield distortion for the grassy knoll shot?
I thought Dr. Chambers was supposed to be a big expert on the acoustics of this case. It sounds like he doesn’t even know the basics. For you or me to make such an error is understandable. Not for Dr. Chambers.
And by the way, I don’t see anything in Dr. Weiss’s testimony that implies the grassy knoll shot would have no windshield distortion. So, I don’t see how Dr. Chambers got that idea, either from the testimony nor from the final report.
Question:
How did Dr. Chambers make two such large errors?
1. Believed the grassy knoll would be off to the side of the motorcycle when it recorded the next to last shot.
2. Believed that Weiss and Aschkenasy found no windshield distortion with the grassy knoll shot.
I see nothing obvious in the testimony or the final report that could lead to such errors.
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How exactly would a stuck microphone confuse the activities in Dealey Plaza?
DUH...communication breakdown just at the exact time of the shooting. Another remarkable coincidence huh? :-\
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When I first heard the police tapes...I came to the conclusion that the "stuck microphone" was a deliberate act to confuse the activities in Dealey Plaza. I still think so.
How exactly would a stuck microphone confuse the activities in Dealey Plaza?
DUH...communication breakdown just at the exact time of the shooting. Another remarkable coincidence huh? :-\
Yes, but my question stands What practicable effect do you think a “stuck microphone” to have?
Do you imagine that without a stuck microphone, the Dispatcher would immediately direct these two policemen to this spot, those two policemen to that spot, maximizing the odds of catching someone? No, the only practicable effect is that without a stuck microphone, the Dispatcher could send in other units to Dealey Plaza immediately to help with the search. But even with an immediate response, it will take many minutes for units to arrive from other parts of Dallas. In the meantime, any shooter can leave the area, even if only moving at a walking pace.
With or without a stuck microphone, either the policemen already at Dealey Plaza are going to, on their own, in the first ten minutes, catch a shooter, or they are not. The radio network, the Dispatcher, policemen who are elsewhere, aren’t going to make a difference in the immediate search.
As it was, what effect did the stuck microphone have on the search? None. Officers, acting without instructions, went looking for the shooter. Officer Baker went into the building and climbed the stairs, on his own initiative. He did not need the Dispatcher to tell him what to do. If the microphone was not stuck, he still would not call in for instructions. That takes too much time and ties up the radio for everyone else. In a situation like this, everyone has to do what they think is best. Any coordination is going to have to come from senior officers already on the spot. Not from the radio network.
And these communication breakdowns, a stuck microphone key, was hardly an unknown event and was always plaguing the police department.
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I’m still a little perplexed about this though. Yes, the windshield would not be in the way of this last shot. But Officer McLain’s torso would have been squarely in the way. So, I am not too impressed with Weiss and Aschkenasy finding no distortion in this last impulse, as they had found in the first three. Why wouldn’t Officer McLain’s torso cause distortions, when the sound waves were forced to bend around his torso, just as the wound waves had to bend around the windshield from the first three shots.
This won't work. The sound waves would have been coming from high above McClain and at a lateral angle from this right. At most, some of the waves might have encountered a portion of the top part of his right shoulder, resulting in minimal distortion, if any.
But the HSCA acoustical experts tested for windshield distortion and found that it significantly weakened the recorded sounds, by 3-6 decibels, when the windshield was between the rifle and the microphone (8 HSCA 31). They also found that shots received from the sides and rear were not affected by the windshield:
Obviously, sounds received from the sides and rear of the motorcycle would not be affected by the windshield. (8 HSCA 31)
Just the fact that the first three shots all contain windshield distortion is an amazing correlation. The fact that the fourth shot shows no such distortion is equally remarkable. The four correlations combined constitute powerful evidence that the dictabelt tape recorded assassination gunfire.
How could Dr. Chambers be ignorant of all this?
How could he not know that for the “grassy knoll” shot, the grassy knoll would be almost directly ahead of the motorcycle?
How could Dr. Chambers have concluded that the Weiss and Aschkenasy found no windshield distortion for the grassy knoll shot?
I thought Dr. Chambers was supposed to be a big expert on the acoustics of this case. It sounds like he doesn’t even know the basics. For you or me to make such an error is understandable. Not for Dr. Chambers.
And by the way, I don’t see anything in Dr. Weiss’s testimony that implies the grassy knoll shot would have no windshield distortion. So, I don’t see how Dr. Chambers got that idea, either from the testimony nor from the final report.
Question:
How did Dr. Chambers make two such large errors?
1. Believed the grassy knoll would be off to the side of the motorcycle when it recorded the next to last shot.
2. Believed that Weiss and Aschkenasy found no windshield distortion with the grassy knoll shot.
I see nothing obvious in the testimony or the final report that could lead to such errors.
Well, hold on now. Let's be fair and accurate about this. Dr. Chambers was correct in saying that the HSCA experts found windshield distortions in the shots that should have contained them and did not find such distortions in the shot that should not have contained them. That, after all, is the main point. He simply misidentified which shot does not contain windshield distortion. It's an error, to be sure, but it does not affect the main point. So it's not like this is some horrendous gaffe.
But, yes, even very good experts with exceptional qualifications make a mistake every now and then.
Dr. Chambers' chapter on the acoustical evidence is far superior to Sturdivan's errant and misleading chapter on the subject.
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This won't work. The sound waves would have been coming from high above McClain and at a lateral angle from this right. At most, some of the waves might have encountered a portion of the top part of his right shoulder, resulting in minimal distortion, if any.
It appears it will work. McLain’s torso should block the direct path to the microphone.
Basic assumptions:
• Microphone is on level with the handle bars, to be easy to reach.
• Microphone is just forward of where the hands hold the handlebars, about 18 to 24 inches in front of the torso.
First, let’s talk about the horizontal angles.
Form previous work, I made a program that calculated the angles and distances for the limousine. At the time the fourth of five “shots” was fired, the motorcycle was in the fourth circle. This works to be about the position of JFK at Zapruder frame z174. At that moment, the horizontal angle back to the TSBD sniper’s nest was 20 degrees. The microphone would be, I think about 18 to 24 inches in front of his torso. Now coming in at a 20-degree angle, the center of the “acoustic shadow” would be displaced to the left by:
Between:
18 * tan (20) = 6.6 inches
And:
24 * tan (20) = 8.7 inches
Where was the microphone? In the center behind the windshield? No.
http://mcadams.posc.mu.edu/russ/jfkinfo2/jfk5/hscashot.htm
Mr. ASCHKENASY - However, they will not look the same, because at the locations where they were picked up the motorcycle was in different orientation relative to the sound source, and as was discussed earlier, the windshield has an effect, the position of the microphone, which we suspect was on the left side of the motorcycle, those all would affect the quality, if I can call it that you know, the shape of the received muzzle blast.
So, the acoustic data that Weiss and Aschkenasy, seemed to indicate the motorcycle microphone was on the left side of the motorcycle.
So, about 6 to 9 inches offset of the acoustic shadow. Officer McLain was pretty big, I understand, so let’s say his torso was 22 inches wide, a bit of a conservative guess. So, his “acoustic shadow” would be offset about 8 inches. So instead of covering everything between -11 to + 11 inches (0 being the center), it would cover more like (-18 to + 4 inches). I doubt the microphone would be outside his hands. I think the maximum to the left it would be would be around -15 inches. So, I think horizontally, the microphone would very likely be in that ‘Acoustic Shadow’.
Of course, one could get around this by saying Weiss and Aschkenasy were mistaken. The microphone was on the right. But this would discredit them. They couldn’t tell from the acoustic data if the microphone was near the left edge of the microphone or the right?
Well, what about the vertical angle. At z174 the angle relative to the street would have been about 23 degrees. The sound wave would have to come down about 15 inches, with the microphone at the same level as his hands. How far would it down?
Between:
18 * tan (23) = 7.6 inches
And:
24 * tan (23) = 10.2 inches
The “acoustic shadow”, 18 to 24 inches in front of Officer McLain, would only come down about 7 to 10 inches, at least 5 inches too high to miss exposing the microphone to a direct line to the sniper’s nest. And this is only taking into account the torso, not the head and helmet.
I think it likely the microphone should be in the acoustic shadow of the torso of Officer McLain.
But the HSCA acoustical experts tested for windshield distortion and found that it significantly weakened the recorded sounds, by 3-6 decibels, when the windshield was between the rifle and the microphone (8 HSCA 31). They also found that shots received from the sides and rear were not affected by the windshield:
Just the fact that the first three shots all contain windshield distortion is an amazing correlation. The fact that the fourth shot shows no such distortion is equally remarkable. The four correlations combined constitute powerful evidence that the dictabelt tape recorded assassination gunfire.
Not that remarkable, since it is likely they should have found distortion in the fifth shot, from the TSBD, due to Officer McLain’s torso. But let’s say they are right. How remarkable is this? One out of five.
Let’s not forget their other scores. They said the shots came from the TSBD, TSBD, TSBD, KNOLL, TSBD. Of the 15 impulse pairs with a strong correlation, how many fit this scenario? First of all, we have to subtract 4, because the determination of whether it was the TSBD or the KNOLL was based on what they felt was the strongest correlation, so those 4 are going to be automatically “right”. Of the other 11 less strong correlations, only 7 of 11 were correct. Not too far from 50-50. Not too impressive.
For the target, comparing where the target should be, based on the time, compared to where the target was, from the acoustic evidence, they were right 4 out of 15 times. About what one would expect from random results with only 4 targets. They were right about 1 out of 4 times.
Location of the limousine? Harder to judge, because I can’t find a good map showing the microphones for the second group ( 2 ( 1 ) through 2 ( 12 ) ). But fairly good but far from perfect. Yes, yes, I know, the correlation with the microphone locations is a “remarkable” match for a motorcycle moving pretty steadily along at 11 mph. A remarkable match, provided one first tosses out all the “false alarms”. Assuming one cherry picks the best microphone locations of the 15 correlations found.
Of course, if I cherry pick the microphone locations from the same data., the results are not so remarkably good.
Shot 1: Motorcycle at 2 (5 )
Shot 2: Motorcycle at 3 ( 5 ), motorcycle has shot forward at high speed and is near where it should be to record the shot at z313
Shot 3: Motorcycle at 2 ( 11 ), motorcycle has reversed course and headed back toward Houston Street
Shot 4: Motorcycle at 3 ( 8 ), motorcycle has reversed course again and is back to following the limousine at high speed.
Shot 5: Motorcycle at 3 ( 5 ), motorcycle has reversed course again and is heading back toward Houston Street a second time.
You see, the remarkable correlation of the data with the expected motorcycle speed depends heavily on which correlations are chosen as “good” and which are chosen as “false alarms”.
And we don’t know, but his may have been assisted by a partial search for matches. Not searching for matches where they couldn’t be. Like looking for a match with an early shot way down Elm street. Or looking for a match for a later shot on Houston Street. We still have no definitive statement from the BBN that all possible 2,592 combinations were hand checked in the 10 days available.
Well, hold on now. Let's be fair and accurate about this. Dr. Chambers was correct in saying that the HSCA experts found windshield distortions in the shots that should have contained them and did not find such distortions in the shot that should not have contained them. That, after all, is the main point. He simply misidentified which shot does not contain windshield distortion. It's an error, to be sure, but it does not affect the main point. So, it's not like this is some horrendous gaffe.
But, yes, even very good experts with exceptional qualifications make a mistake every now and then.
Dr. Chambers' chapter on the acoustical evidence is far superior to Sturdivan's errant and misleading chapter on the subject.
No. Dr. Chamber’s gaffe is pretty serious.
He wrote a book about the assassination. He wrote a chapter about the acoustics. He gave us the impression that he was looking independently into the evidence, and found that Weiss and Aschkenasy did analyze the evidence correctly. But we know he did not do this.
• He did not look at the waveforms for the “grassy knoll” shot and found that there were, indeed, no distorted waveform there. We know that because Weiss and Aschkenasy did find this waveform to be distorted.
• He did not check the BBN map, as I did, to make certain that Weiss and Aschkenasy were correct that the motorcycle position would not cause the windshield to distort the sound from the grassy knoll shot.
• He didn’t even check the HSCA reports to confirm that it was, indeed, the grassy knoll shot that would not cause windshield distortion, according to Weiss and Aschkenasy.
Oops.
Instead, it looks like Dr. Chambers just went with his impressions, that Weiss and Aschkenasy said the grassy knoll shot should not contain windshield distortions, and indeed did not contain windshield distortions, and just rubber stamped the claim he thought they had made. And said, “yes, they got it right alright”. That is what it looks like to me. Not impressive.
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In order to fully understand and appreciate the HSCA acoustical evidence, one must understand the phases and nature of the acoustical analysis.
* When BBN received the Dallas police dictabelt recording, they understood that “if gunfire had been recorded on Channel 1, the analysis of that tape could be expected to reveal patterns of transient waveforms that would be generally characteristic of the shock wave produced by the bullet, of the loud and impulsive noise of the muzzle blast, and of echoes of each” (8 HSCA 42). They also knew that “it could further be expected that the major components of the shock wave would appear in the 1-kHz to 3.2-kHz frequency band” (8 HSCA 42).
Thus, the BBN experts knew that, if they were dealing with impulse patterns caused by gunfire, each of their sounds would come in a specific order: they knew that the shock wave (or N-wave) would come first, followed by the muzzle blast, followed by echoes of the shock wave and the muzzle blast. They also knew that the presence of these patterns would depend on whether the microphone was in position to record them.
* In order to determine if gunshot waveform patterns were present on the police tape, the BBN acoustical scientists first had to apply two filters to the tape to filter out sounds that were outside the 1.0 to 3.2-kHz frequency band and to filter out background noise, especially the engine noise, that could mask the presence of gunshot-like impulse patterns.
* BBN applied the two filters to the entire 5-minute police tape (8 HSCA 42).
* BBN then took the recorded outputs from both filters for the entire 5-minute tape and converted the sounds into images, such as oscillograms and spectrograms, so that they could analyze the impulse patterns in minute detail. An example:
(https://www.maryferrell.org/wiki/images/0/00/Pict_essay_acousticshistory_NoiseLevel.jpg)
* The BBN scientists then analyzed the peaks and lines of all the impulses on the dictabelt recording. They did not just examine this or that part of the graphically displayed tape, but the entire tape.
* Also, at this point, the BBN scientists did not know if any of the impulse patterns would pass the initial five gunfire screening tests, and they had no idea which motorcycle may or may not have recorded gunfire in Dealey Plaza. They were simply looking for any and all patterns that resembled waveforms with the general characteristics of gunshots.
Keep in mind that they had no test-firing data from Dealey Plaza yet, because the test firing had not yet been conducted. Also keep in mind that they had not yet even subjected any of the impulse patterns to the five screening tests.
* When the BBN scientists analyzed the graphical representations of all of the dictabelt tape’s impulse patterns, they found six patterns that they believed should be subjected to the five screening tests.
* BBN then applied the five screening tests to the six impulse patterns. If a pattern failed even one of the screening tests, it was disqualified from further analysis. Five of the six impulse patterns passed the screening tests.
The one pattern that did not pass failed three of the five screening tests: it failed the test for duration, the test for amplitude, and the test for shape. The test for shape examined whether the impulses within the pattern resembled the general characteristics of a shock wave and a muzzle blast.
Until today, I believed that the failed impulse pattern—the 4-second pattern discussed in previous replies--failed two of the five screening tests, but a closer reading of the BBN report clearly shows that it failed three of them. The BBN report notes that the 4-second impulse pattern was not only too short and of insufficient amplitude, but that it lacked “shapes similar to the expected characteristics of a shock wave and of a muzzle blast,” whereas the five other impulse patterns had those characteristics (8 HSCA 43).
This was the end of the preliminary analysis.
* At this point in time, the BBN scientists had no information on any motorcycle’s location in Dealey Plaza; they had no microphone-location data from the test firing to determine any possible motorcycle positions; and they did not even know if any of the five passing impulse patterns would pass the far more rigorous analyses based on the test-firing data.
* After studying the results of the screening tests in the preliminary analysis, the BBN scientists contacted the HSCA and advised the committee that they needed to conduct a test firing in Dealey Plaza before they could do further analysis of the dictabelt recording. The HSCA then asked two acoustical experts from Queens College, Mark Weiss and Ernest Aschkenasy, to review the BBN analysis and the BBN test-firing plan. WA found the BBN analysis to be accurate and the BBN reconstruction plan to be sound.
* The Dealey Plaza test firing was then conducted. Shots were fired from two locations: the sixth-floor Texas School Book Depository window that Oswald allegedly used and a spot on the grassy knoll. 36 microphones were placed on Houston Street and on Elm Street to record the sounds of the shots.
* The impulse patterns from the test-firing shots were then compared with the dictabelt impulse patterns that passed the gunfire screening tests. All five of the dictabelt impulse patterns were found to match patterns of some of the test-firing shots. The matches were based on the echo patterns of the respective impulse patterns. The odds that these correlations were due to chance are astronomically low.
We can suppose that one or perhaps two random noise patterns might, by rather remarkable chance, match the echo patterns of shots fired in Dealey Plaza within a 10-second period. But the idea that random noise patterns would match the echo patterns of five shots fired in Dealey Plaza within a 10-second period seems impossibly far-fetched.
And note that the acoustical scientists had not yet attempted to determine if the matches occurred in the correct topographic (locational) order in relation to the movement of the motorcycle. So the suggestion that the BBN scientists "only checked for matches where they anticipated where the motorcycle might be" is not only erroneous but displays a misunderstanding of the nature and timeline of the acoustical analysis.
* When the HSCA acoustical scientists studied the correlations further, they made two surprising discoveries. They found that when the locations of the microphones that recorded the matches were plotted on a graph showing time and distance, the microphones were grouped around a line on the graph that matched the known average speed of JFK’s limousine on Elm Street.
More important, they found that the matches occurred in the correct topographic (locational) order. The first dictabelt gunshot impulse pattern matched a test shot recorded on a microphone on Houston Street, close to the intersection with Elm Street. The next dictabelt gunshot impulse pattern matched a test shot recorded at the next microphone farther north on Houston Street. The third dictabelt gunshot impulse pattern matched a test shot recorded on a microphone in the intersection of Houston and Elm. The fourth dictabelt gunshot impulse pattern matched a test shot recorded on a microphone farther down on Elm Street. And the fifth dictabelt gunshot impulse pattern matched a test shot recorded on the next microphone on Elm Street.
The odds that these stunning topographic correlations could be coincidence are 125 to 1 against. Why? Because there are 125 ways that any five events can be sequenced, e.g., 5-2-4-1-2, 2-1-4-5-3, 4-5-3-1-2, 3-5-4-2-1, 3-2-4-1-5, etc., etc. Only one of those 125 ways is 1-2-3-4-5. In other words, the odds that these locational correlations are the result of chance are 124 out of 125, or 99.20%, against.
* The HSCA acoustical experts found four more impressive correlations.
They found that each dictabelt gunshot impulse pattern that was recorded when the motorcycle was in position to record the shot’s N-wave does in fact include an N-wave.
They found that in each shot with an N-wave, the N-wave comes in the correct order and interval in relation to the muzzle blast that comes behind it. When a rifle shot is fired, the first sound to reach a properly placed microphone will be the N-wave, followed by the muzzle blast, followed by the echoes of the N-wave and of the muzzle blast. N-waves come 10-30 milliseconds before the muzzle blast, depending on the rifle’s muzzle velocity and other factors. The N-wave in the dictabelt grassy knoll shot comes 24 milliseconds before the muzzle blast.
They found that each shot with an N-wave includes echoes of the N-wave and of the muzzle blast, as it should, and that the echoes come in the correct order and interval in relation to the N-wave and the muzzle blast.
Finally, the HSCA experts found that windshield distortion occurs in the dictabelt gunshots where it should occur, and does not occur in the one gunshot where it could not have occurred. The HSCA acoustical experts tested for windshield distortion because they knew it could substantially affect how the sounds of gunshots were recorded. They found that the dictabelt impulse patterns that contain windshield-distortion characteristics were recorded when the motorcycle’s windshield was between the shooter and the microphone. Conversely, they found no signs of windshield distortion in the one dictabelt impulse pattern that was recorded when the windshield was not between the shooter and the microphone. These are stunning correlations.
The HSCA report’s comments on the windshield-distortion correlations deserve another reading:
Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone. On shot four, Weiss and Aschkenasy found no such distortion.(55) The analysts' ability to predict the effect of the windshield on the impulses found on the dispatch tape, and having their predictions confirmed by the tape, indicated further that the microphone was mounted on a motorcycle in Dealey Plaza and that it had transmitted the sounds of the shots fired during the assassination. (HSCA report, pp. 74-75)
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More important, they found that the matches occurred in the correct topographic (locational) order. The first dictabelt gunshot impulse pattern matched a test shot recorded on a microphone on Houston Street, close to the intersection with Elm Street. The next dictabelt gunshot impulse pattern matched a test shot recorded at the next microphone farther north on Houston Street. The third dictabelt gunshot impulse pattern matched a test shot recorded on a microphone in the intersection of Houston and Elm. The fourth dictabelt gunshot impulse pattern matched a test shot recorded on a microphone farther down on Elm Street. And the fifth dictabelt gunshot impulse pattern matched a test shot recorded on the next microphone on Elm Street.
The odds that these stunning topographic correlations could be coincidence are 125 to 1 against. Why? Because there are 125 ways that any five events can be sequenced, e.g., 5-2-4-1-2, 2-1-4-5-3, 4-5-3-1-2, 3-5-4-2-1, 3-2-4-1-5, etc., etc. Only one of those 125 ways is 1-2-3-4-5. In other words, the odds that these locational correlations are not the result of chance are 124 out of 125, or 99.20%.
Mr. Griffith corrected me on proper English, on when to use “it’s” and “its”. Something I should have learned in high school. Let me correct him on a little math on something he should have learned in high school.
What are the odds of five things ending up in the correct order? One out of 125? How did he get that? Five to the third power?
No, the number of permutations of a set with “n” members is n-factorial. This is: n * (n-1) * (n-2) * . . . 2 * 1. So, the number of ways to order a set with 5 members is 120.
Now, what about the remarkable order of the apparent position of the motorcycle over time. How it appears to be moving up Houston and then down Elm Street at a study pace. Well, it turns out, that this depends heavily on cherry picking the data, as the BBN did. For instance, the BBN found correlations for the microphones for the first “shot” at microphones 2 ( 5 ), 2 ( 5 ), 2 ( 6 ) and 2 ( 6 ). Quite good. For the second “shot” at microphones 2 ( 6 ), 2 ( 6 ), 2 ( 10 ) and 3 ( 5 ). Wildly bad. They found correlations along a stretch of about 84 feet along Houston and Elm. But the rest were not as bad.
If you make careful selections of which correlation that is considered “good”, then for the 5 shots (including Dr. Thomas’s fifth shot) you get:
2 ( 5 ), 2 ( 6 ), 2 ( 11 ), 3 ( 4 ) and 3 ( 5 ). If the first microphone at 1 ( 1 ) is considered at distance 0, and we assume a distance of 12 feet between each microphone, we get distances along this track of:
168, 180, 204, 252, 264 feet.
Note: These distances are very rough. And the second section of microphones 2 ( 1 ) through 2 ( 12 ), is much shorter than the other two, because they did not arrange these microphones in a linear line but bunched them up over a short distance around the bend of Houston to Elm, where the street was widest.
Ok. This is quite good. We get a nice steady pace of around 11 mph. Sounds quite plausible.
But what if we make a different selection of which correlations are considered good? In that case we can get:
2 ( 5 ), 3 ( 5 ), 2 ( 11 ), 3 ( 8 ), 3 ( 5 ). This gives us the distances along this track for the 5 shots of:
168, 264, 204, 300, 264 feet.
This gives us a much more erratic pattern. It appears the motorcycle initially speed forward at a tremendous speed between shots 1 and 2, then reversed direction to head back toward Houston to record the third shot, then again reversed direction and rode down Elm Street to record the fourth shot, before reversing direction for the third time and heading back toward Houston to record the fifth shot.
You see, a lot depends on which correlations you decide you like. And which ones you decide to reject as “false alarms”.
Ok, let’s do it one more time. This time, not trying to make the data look good or bad. Whatever correlation we get, we will accept its position, then select the average of all the correlations for that shot. In that case, we get the distances of:
174, 207, 204, 280, 280 feet.
Well, not too bad. A couple hiccups here and there. An apparent reversal between the second and third shot. And the motorcycle appears stopped for the fourth and fifth shot. But still, not too bad.
Well, why didn’t they do the obvious thing? Make their position estimate of the motorcycle based on the average result they got from their data. Because their data seemed in many ways to be random.
For different widely space targets were used. Of the 15 found correlations, only 4 corresponded with the location of the limousine at that time. About a success rate of 1 in 4, exactly as to be expected with random results.
For the source of the gunfire, the correlations were not consistent. Of the four judged shots with multiple correlations, three of them gave two different location for the source of the fire, the TSBD and the Grassy Knoll. Only the last shot, with three correlations, did all three agree on the same source, the TSBD. Of the 12 test shots, 8, or 67 percent came from the TSBD. Of the 15 found correlations, 12, or 80 percent, came from the TSBD. Again, the results are close to what one would expect of random data.
Only with the location of the limousine could a case be made for good, non-random data. Provided the data was cherry picked. If this was done, then it could be argued, as the BBN did, that the data supports a plausible, fairly constant 11 mph speed for the motorcycle with the stuck microphone.
But how did they make their case? Did the propose using cherry picked data. And also presented arguments in favor of using all their data, and using the average location to show the position of the motorcycle. But argue for why the cherry-picked method is better. No. they never made any arguments about why using cherry picked data is superior to using the averages of the data. They simply presented their cherry-picked data, in the form of a map of Dealey Plaza with four circles, nicely spaced, which support a near constant speed of 11 mph for the motorcycle.
One can still argue, well maybe there is not a 1 in 120 chance that we get such a correlation of the speed of the motorcycle with a 11-mph steady progress. But the data is consistent with a motorcycle progressing up Houston and Elm in generally the right direction. This suggests that the data is not random. But there is one more thing to considered, beyond cherry picking which correlations to use, that could skew the data. And that is deciding which part of the raw data to search for comparisons. It would be natural to assume they searched for all possible 2,592 combinations, of the:
• 432 recordings from the 1978 tests, 36 microphones, each recording 12 test shots.
with:
• The six suspect impulses from the 1963 Dictabelt recording.
But they had only 10 days to do all these comparisons, and the associated calculations, to find the strongest correlations. So, it is plausible they only searched for where there could be a valid correlation. So, after finding one shot, likely the second, skip searching the hundreds of possible comparisons of early shots with the microphones that are on Elm Street, where they couldn’t be. And skip searching the hundreds of possible comparisons of the later shots along Houston Street and around the bend, where they couldn’t be. This approach may have been dictated by time constraints, 10 days between the shooting tests and the making of the phone call to the HSCA reporting on the finding of 15 correlations.
And the search may have been a good deal more focused than that. After finding one shot, let’s say the second shot, they might initially search the section that is consistent with a 11 mph for the first shot. Upon finding random correlations that convince them that the motorcycle is indeed moving at about the same speed as the limousine, they could do the same with the third, fourth and fifth shot, resulting in data that matches fairly well, with a 11-mph motorcycle. Even though the data is random noise.
BBN did all they could to make the case that their data was good. Cherry picked their data. Drew a map with 4 circles that showed how consistent this cherry-picked data was with a 11-mph motorcycle. If there was more there could have been done, they would have done it.
They could have said “It takes about ‘x’ minutes to make one comparison and the associated calculations”. The rate can be maintained for 6 hours during a hard-working day. We had ‘y’ men on this job. After a couple of days, we could process ‘z’ combinations per day. By the eighth day, we had completed all 2,592 combinations. This would help nail down the somewhat good correlation with the data and the location of the motorcycle. But there is no statement to this effect. No statement that unequivocally states that all 2,592 comparisons where actually done and completed.
Combined with the randomness of the data, except in regards as to the apparent speed of the motorcycle, I believe that only a subset of the 2,592 comparisons was actually made.
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Yes, but my question stands...
That is [I guess] agreement that it was another 'remarkable coincidence'. To quote your previous statement...."What are the odds"? And these communication breakdowns, a stuck microphone key, was hardly an unknown event and was always plaguing the police department.
Really? I would like to see some documentation of this.
I believe this acoustical jive is a waste of web space so if you don't reply...no loss of skin.
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That is [I guess] agreement that it was another 'remarkable coincidence'. To quote your previous statement...."What are the odds"? Really? I would like to see some documentation of this.
I believe this acoustical jive is a waste of web space so if you don't reply...no loss of skin.
If there are no compelling reasons for the conspirators to shut down Channel 1 for about 5.5 minutes, and only about the first 3 minutes after the assassination, then, yes, I think this should be looked at as a coincidence.
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Remember, the BBN’s claim that they found gunshots recorded does not rest on them finding sound impulses on the recording. There are sound impulses throughout the recording. This claim solely rests on the correlations found between their 1978 firing tests and the 1963 Dictabelt recording. So, their claim rests on the strength of Exhibit F-367, a table of all found correlations. Do these correlations seem good? Do they contradict themselves? Do they make sense?
How to Analyze Data. How to recognize random data.
Let’s say the BBN analyzed all the found correlations and produced a table of them and ended up something like this:
********** False Table used only to make a point **********
Shot 1: from-TSBD fired-at-Target-1 correlation:9
Shot 1: from-KNOLL fired-at-Target-3 correlation:6
Shot 1: from-TSBD fired-at-Target-3 correlation:7
Shot 2: from-TSBD fired-at-Target-1 correlation:7
Shot 2: from-KNOLL fired-at-Target-2 correlation:9
We have correlations that contradict each other. We find correlations that match the first shot with a test shot from the TSBD and the KNOLL. Does this mean the data is bad? That we may be looking at random data?
No necessarily. It may mean we have set our correlation threshold too low. Allowing us to find some correlations that are real, but also others that are not, just due to a fluke. Setting the correlation threshold too low collects the good correlations but will also collect the false correlations. So, the next thing to do is select a higher correlation, like 9, and see what that gives us:
********** False Table used only to make a point **********
Shot 1: from-TSBD fired-at-Target-1 correlation:9
Shot 2: from-KNOLL fired-at-Target-2 correlation:9
This is much better. We don’t have any correlations that contradict each other. If we had such a table for 4 shots, and they were consistent with BOTH the location of the microphone and the location of the target, then we may have good data. It would meet the minimum qualifications.
For the real BBN data from Exhibit F-367 we have correlations that contradict each other. For 3 of the 5 shots, correlations are found for both a shot from the TSBD and a shot from the Grassy Knoll. Clearly, we have the correlation threshold set too low. The only way to eliminate the contradictions is to raise the threshold from 6 to 8. If this is done, we get:
********** The real data, with the correlation threshold set at 8 **********
| Test | Beginning Time of | Zap. | Zap. | Microphone Array | Rifle | Target | Correlation | Strong | Fluke |
| ID | First impulse on | Frame | Frame | and | Location | Location | Coefficient** |
| | Tape Segments (sec) | BBN | Thomas | (Channel Numbers) |
| |
| |
| |
| B | 137.70 | 168 | 176 | 2 ( 5 ) | TSBD* | 1 | 0.8 | Strong |
| D | 137.70 | 168 | 176 | 2 ( 6 ) | TSBD | 3 | 0.8 | Strong | Fluke |
| |
| |
| |
| G | 139.27 | 196 | 205 | 2 ( 6 ) | TSBD* | 3 | 0.8 | Strong |
| |
| |
| |
| L | 145.15 | 304 | 313 | 3 ( 4 ) | KNOLL | 3 | 0.8 | Strong |
| |
| |
| |
| O | 145.61 | 313 | 321 | 3 ( 5 ) | TSBD | 3 | 0.8 | Strong | Fluke |
| P | 145.61 | 313 | 321 | 3 ( 6 ) | TSBD | 4 | 0.8 | Strong |
| |
| |
| |
First of all, it was necessary to eliminate the Dr. Thomas shot. The problem was not that it only had one correlation to support it. That was actually a good thing. The problem was its correlation was too low, at 6. It should have a stronger correlation of 8, like all our remaining strong candidates
But even these ‘strong’ candidates have problems.
For the first shot, we have a contradiction. We found correlations for both a shot at Target 1 and Target 3. Those targets are over one hundred feet apart. And only a result of Target 1 makes sense for such an early shot. In any case, a correlation of 8 is still not high enough to eliminate all the random correlations.
Also, for the first shot, if one argues the waveform would be similar for both Target 1 and 3, why did the BBN test firing at different targets? Why not just use the same target if the target location makes little or no difference? Clearly, they thought that it would make a difference. And why didn’t they get a strong correlation for Target 2 when it was tried. Strong correlation for Targets 1 and 3, but not for Target 2 which was in between? It looks like random results.
For the second shot, we have no contradictions. We found one correlation which is good. Ideal really, But the correlation found is for Target 3. It should have been found for only Target 1 or 2, or both, since the limousine would have been between both targets. But not at Target 3. Why would they get a strong correlation for Target 3 but not for Target 1 or 2? It looks like we got another random match. A correlation of 8 is still not high enough to eliminate all the random correlations.
For the third shot, no problem. Only one correlation found, which is ideal. A shot at Target 3, which is good, right where the limousine should be. If only the other shots had no clearly random results.
For the fourth shot, we have contradictions. Correlation with both Target 3 and 4, which are 240 feet apart. We should only find a correlation for Target 3. Again, a correlation of 8 is still not high enough to eliminate all the random correlations.
At this stage we should try setting the correlation threshold higher. But we can’t. The highest correlation in the data is 0.8. If we set it any higher, we have no more correlations.
This data looks like random data, particularly with the correlation threshold set at 6.
The Target locations seem random and do not track the real limousine location. Only 4 of 15 correlations give good Target locations, which is no better than random luck.
The shooter locations contradict themselves, with 3 of the 5 shots matching test shots from both the TSBD and the Grassy Knoll. In the 1978 12 test shots, 67 percent of the shots came from the TSBD and a similar 80 percent of the correlations were from the TSBD. This again looks like it could be random data.
Only the motorcycle location seems good, if the data is cherry-picked. But this may also be a factor of the BBN only checking the areas where the motorcycle could be, if travelling at a steady 11 mph. Naturally, any correlation found would match that of a motorcycle moving at a steady 11 mph.
If the data looks random, that is a fatal flaw. Writing up a bunch of words like the BBN did in their report is like putting lipstick on a pig. The BBN case stands or falls with F-367. And it falls.
Mr. Griffith will try to draw the readers attention away from BBN’s Exhibit F-367. Or if he does deal with it, he will only want to discuss the motorcycle position correlation, which may be a result of which data the BBN decided to analyze. He won’t want to talk about the correlations dealing with the shooter location or the Target location. And not discuss why a correlation of only 6, the Dr. Thomas shot, should be taken seriously.
Let’s see if he can use Table F-367 to defend Table F-367.
-
In my previous reply, I explained the timeline and nature of the HSCA acoustical analysis. However, I purposely did not go into much detail on the grassy knoll shot, because that would have made the reply about 50% longer, and it was already long enough. When you understand how Weiss and Aschkenasy (WA) confirmed the grassy knoll shot, you more fully understand the powerful nature of the acoustical evidence.
* The grassy knoll shot is the 145.15 shot, the third of the four shots that the HSCA acknowledged on the dictabelt recording. The BBN scientists noted that this was shot was aimed at JFK when the limousine was “near the limousine position seen in frame 313” (8 HSCA 6).
* The main reason that WA were asked to review the BBN analysis was that BBN said the grassy knoll shot had a certainty factor of only 50%. Everyone recognized that if the 145.15 shot was confirmed to be a shot from the grassy knoll, this would automatically prove that more than one gunman fired at JFK, since no one doubted that at least one shot was fired from behind, and since the sixth-floor gunman could not have fired a shot from the grassy knoll.
BBN said the three other shots had much higher certainty factors:
1st shot: 88% (based on three matches)
2nd shot: 88% (based on three matches)
4th shot: 75% (based on two matches)
* The third shot had a 50% certainty factor because it matched one test-firing shot from the grassy knoll but matched two test-firing shots from the TSBD. The grassy knoll match had a correlation coefficient of 0.8, a very high coefficient, whereas the two TSBD matches had a correlation coefficient of 0.7. Only five other matches of the 15 matches (really correlations) had a coefficient of 0.8. Based on this fact and on other factors, the BBN scientists concluded that the third shot came from the grassy knoll, but they knew that a more-refined analysis was needed to confirm this and to prove that the two TSBD matches were false matches.
The BBN scientists knew that the locations of the microphones in the test-firing caused false alarms/false matches because they did not know the exact location of the motorcycle in a given 18-foot interval:
The correlation detector produced several false alarms that could be identified as such. These false alarms are spurious matches caused by uncertainty of the exact motorcycle position with respect to the known positions of microphones used in the reconstruction test. . . . (8 HSCA 7)
The BBN scientists suspected that if they had used more microphones so that the microphones had been closer to each other, the two TSBD matches on the third shot would not have occurred.
* WA realized that the problem was that the microphones in the test firing were spaced 18 feet apart. The 18-foot spacing was the reason that BBN applied a 6-millisecond acceptance window when determining matches, since, as BBN explained, they could not be certain where the motorcycle was in a given 18-foot interval:
Because of the spacing of the microphones and lack of knowledge of the precise position of the motorcycle within the motorcade, it was fudged that the motorcycle would, in the worst case, have been no more than 18 ft away from a microphone location. The most likely separations were accounted for . . . by the establishing of a ±6-msec acceptance window for matching echo and impulse patterns. (8 HSCA 97)
* As WA explained in their testimony, they did not need to do another test firing in Dealey Plaza to solve the microphone-spacing problem. They knew they could do a computerized sonar analysis that would duplicate the conditions of closer microphone spacing--1 foot apart instead of 18 feet apart--and the resulting echo patterns. They wrote a sonar analysis program that simulated an echo pattern for 180 locations surrounding the location of the test microphone that gave the best match for the third dictabelt impulse pattern, i.e., the grassy knoll shot.
WA had written similar sonar analysis programs for the U.S. Navy—that was one of the reasons the Acoustical Society of America recommended them to the HSCA.
* Significantly, the sonar analysis enabled WA to reduce the acceptance window for a match from 6 milliseconds down to 1 millisecond, a 500% narrower window, which vastly reduced the possibility of a false match. 1 millisecond is one one-thousandth of a second. To be counted as a match, a dictabelt impulse and a test-shot echo pattern had to correspond to each other within the incredibly short timeframe of 1 millisecond.
WA also applied a noise threshold to further distinguish between non-gunfire noise and gunfire impulses.
* When WA conducted the solar analysis, they found that the dictabelt grassy knoll shot was a nearly perfect match for a test shot from the grassy knoll, which was fired from a position 8 feet west of the corner of the picket fence on the grassy knoll.
In the first sonar analysis comparison, done without the noise threshold, WA found that when the muzzle blast of the test shot was aligned with the first large impulse of the 145.15 shot—the grassy knoll shot—all 26 echoes of the test shot occurred within 1 millisecond of a corresponding impulse of the 145.15 shot.
In the second sonar analysis comparison, WA found that when they applied the noise threshold, the grassy knoll shot had 14 large impulses compared to the 12 large impulses of the test-shot pattern. Crucially, 10 of the 12 impulses in the test shot matched impulses in the grassy knoll shot to within 1 millisecond. This is an astounding correlation. Dr. Weiss explained:
Now we didn't want to include anything that might be noise in this comparison; we wanted to deal only with things of which we could be reasonably certain. So we excluded from the consideration anything which was at the noise level itself. If we knew it was below that level, then it was more probably noise than anything else, we excluded it. We wanted to know: do those things that excessed this noise level match? Well, if so, how many are there, how many do we expect to find, and how many are matched?
The answer to those three points is that there are a total of some 14 of these greater-than-noise-level peaks observed; there are a total of 10 of them that, in fact, correspond very closely to echo paths that we have been able to predict [in the simulated echo patterns].
Now our predictions also show that we should have had 12 larger-than-noise-level peaks present; but if you take these numbers and put it in an equation or formula known as the binary correlation formula, you get a number, known as a binary correlation coefficient, of .77, which says, in effect, that this pattern matches, is matched by a corresponding pattern of strong echoes with a coefficient of .77.
If you take that now and you say, well, what is the probability that this is noise, that it is just an accident that these impulses happened to fall into this sequence of spacings, the answer that you get then is that the probability that this is noise is less than 5 percent. (5 HSCA 570)
* Dr. Barger explained the importance of the WA analysis:
Mr. WOLF . In your testimony on September 11, addressing particularly the third impulse in the Dallas Police dispatch tape, you stated that the probability of this being a shot from the grassy knoll was 50-50. Professor Weiss and Mr. Aschkenasy, today, whose testimony you heard, stated that the probability of this being a shot from the grassy knoll was 95 percent or better. You have reviewed the work of Professor Weiss and Mr. Aschkenasy. Do you agree with their assessment?
Dr. BARGER. Yes; once we checked their procedures, their parameters and their echo-producing objects, we received from them the results of their match. Drs. Kalikow, Rhyne, and Mr. Schmidt and I, at Bolt, Beranek, and Newman, reviewed their results, and we concluded that they had successfully achieved a match having a correlation coefficient of .77, and you remember that was the number I was using of goodness of match. We also found that they had done this with only a plus or minus one one-thousandth of a second error for each match, whereas we had used a plus or minus six one-thousandths of a second error window, if you will, or acceptance window as Professor Weiss called it, in order to achieve our matches.
Now, the reason that we used the large acceptance window of six one-thousandths of a second was because we didn't know, as I said, exactly where the motorcycle was. The reason they were able to lower theirs to one one-thousandth of a second was because they found exactly where it was by the procedure they described this morning. The effect of reducing this acceptance window is to greatly reduce the likelihood that noise bursts that occur could mimic the fingerprint of a shot from any place and received at that microphone. It reduces it very substantially. In other words, in the terminology that I used last time, their ability to achieve this match within plus or minus one one-thousandth of 1 second reduces the false alarm rate substantially. In other words, we had a large false alarm rate because we had a large acceptance window because we didn't know exactly where the motorcycle was. That gave us a large false alarm rate. They corrected that problem by lowering the acceptance window.
There is another feature of that score besides the acceptance window that is important. That is the value of the correlation coefficient achieved. As I said, we would not accept as a potential match any correlation coefficient that was less than one-half. But we didn't require it to be one, either, which is what it would be if there was no noise. Noise is the thing that causes the correlation coefficient to be less than one. Noise is on the Dallas Police recording.
Professors Weiss and Aschkenasy did nothing to reduce the noise, so I would not have expected they would have increased the correlation coefficient. In fact, they accepted more noise than we did, and that could have affected the correlation coefficient, which should have gone down. So their correlation coefficient, while high, was not unity. On the other hand, the false alarm rate one would expect from their match, which was so tight, this would make the likelihood of random noise bursts to fit all 10 of those to within plus or minus one one-thousandth very small.
Mr. WOLF. Your ability to state with 95-percent certainty, now, what was only a 50-50-percent probability in September was, in essence, due to the narrowing of the match time from six one-thousandths of a second to one one-thousandth of a second. Is that, in essence, correct?
Dr. BARGER. Yes, sir. After looking at what they had done, and the fact they had maintained a high correlation coefficient while reducing the acceptance window, resulted in our independent calculation of the expectancy that they could have achieved the match they got only 5 percent of the time by random if it had just been noise on the tape and not a gunshot from that place. That is why we stated independently, although their number was quite similar to ours, that we felt that the likelihood of there having been a gun shot from that knoll and received at that point now to be about 95 percent or possibly better. (5 HSCA 673-674)
* Actually, due to the fact that the two groups of HSCA acoustical experts worked separately, a math error arose in the calculation of the odds relating to the grassy knoll shot. The probability that the grassy knoll shot was the result of random noise was computed to be less than 5%, or less than 1 in 20, based mainly on a miscalculation of the value of p in the formula. The actual odds are even lower than WA calculated. Dr. Donald Thomas has demonstrated that they are actually only 1 in 100,000, or 100,000 to 1 against (http://jfklancer.com/pdf/Thomas.pdf). Put into percentage terms, the probability that chance produced the grassy knoll shot is 0.001%. To put it another way, the probability that the grassy knoll shot is a gunshot is 99.999%.
Interestingly, in their report, WA pointed out that they had been conservative in calculating the odds that chance had produced the matches between the grassy knoll shot's impulses and the test shot's echo patterns, and that the odds that chance had caused such a high degree of correlation were "considerably less than 5 percent":
The high degree of correlation between the impulse and echo sequences does not preclude the possibility that the impulses were not the sounds of a gunshot. It is conceivable that a sequence of impulse sounds, derived from non-gunshot sources, was generated with time spacings that, by chance, corresponded within one one-thousandth of a second to those of echoes of a gunshot fired from the grassy knoll. However, the probability of such a chance occurrence is about 5 percent. This calculation represents a highly conservative point of view, since it assumes that impulses can occur only in the two intervals in which echoes were observed to occur, these being the echo-delay range from 0 to 85 milliseconds and the range from 275 to 370 milliseconds. However, if the impulses in the DPD recording were not the echoes of a gunshot, they could also have occurred in the 190-millisecond timespan that separated these two intervals. Taking this timespan into account, the probability becomes considerably less than 5 percent that the match between the recorded impulses and the predicted echoes occurred by chance. (8 HSCA 32)
* Revealingly, the NRC panel recognized that WA had assigned the wrong value for p in their calculations; however, the panel not only failed to tell their readers that WA had overestimated the odds that the grassy knoll shot was random noise, but they used erroneous assumptions in their own calculations to make it seem like there was a 22% chance that the grassy knoll shot was random noise.
Yes, in so doing, the NRC panel was admitting there was a 78% chance that the grassy knoll shot was a gunshot, but 78% is quite a bit lower than 95%+, and far lower than 99.999%.
-
In my previous reply, I explained the timeline and nature of the HSCA acoustical analysis. However, I purposely did not go into much detail on the grassy knoll shot, because that would have made the reply about 50% longer, and it was already long enough. When you understand how Weiss and Aschkenasy (WA) confirmed the grassy knoll shot, you more fully understand the powerful nature of the acoustical evidence.
* The grassy knoll shot is the 145.15 shot, the third of the four shots that the HSCA acknowledged on the dictabelt recording. The BBN scientists noted that this was shot was aimed at JFK when the limousine was “near the limousine position seen in frame 313” (8 HSCA 6).
* The main reason that WA were asked to review the BBN analysis was that BBN said the grassy knoll shot had a certainty factor of only 50%. Everyone recognized that if the 145.15 shot was confirmed to be a shot from the grassy knoll, this would automatically prove that more than one gunman fired at JFK, since no one doubted that at least one shot was fired from behind, and since the sixth-floor gunman could not have fired a shot from the grassy knoll.
BBN said the three other shots had much higher certainty factors:
1st shot: 88% (based on three matches)
2nd shot: 88% (based on three matches)
4th shot: 75% (based on two matches)
* The third shot had a 50% certainty factor because it matched one test-firing shot from the grassy knoll but matched two test-firing shots from the TSBD. The grassy knoll match had a correlation coefficient of 0.8, a very high coefficient, whereas the two TSBD matches had a correlation coefficient of 0.7. Only five other matches of the 15 matches (really correlations) had a coefficient of 0.8. Based on this fact and on other factors, the BBN scientists concluded that the third shot came from the grassy knoll, but they knew that a more-refined analysis was needed to confirm this and to prove that the two TSBD matches were false matches.
The BBN scientists knew that the locations of the microphones in the test-firing caused false alarms/false matches because they did not know the exact location of the motorcycle in a given 18-foot interval:
The BBN scientists suspected that if they had used more microphones so that the microphones had been closer to each other, the two TSBD matches on the third shot would not have occurred.
* WA realized that the problem was that the microphones in the test firing were spaced 18 feet apart. The 18-foot spacing was the reason that BBN applied a 6-millisecond acceptance window when determining matches, since, as BBN explained, they could not be certain where the motorcycle was in a given 18-foot interval:
* As WA explained in their testimony, they did not need to do another test firing in Dealey Plaza to solve the microphone-spacing problem. They knew they could do a computerized sonar analysis that would duplicate the conditions of closer microphone spacing--1 foot apart instead of 18 feet apart--and the resulting echo patterns. They wrote a sonar analysis program that simulated an echo pattern for 180 locations surrounding the location of the test microphone that gave the best match for the third dictabelt impulse pattern, i.e., the grassy knoll shot.
WA had written similar sonar analysis programs for the U.S. Navy—that was one of the reasons the Acoustical Society of America recommended them to the HSCA.
* Significantly, the sonar analysis enabled WA to reduce the acceptance window for a match from 6 milliseconds down to 1 millisecond, a 500% narrower window, which vastly reduced the possibility of a false match. 1 millisecond is one one-thousandth of a second. To be counted as a match, a dictabelt impulse and a test-shot echo pattern had to correspond to each other within the incredibly short timeframe of 1 millisecond.
WA also applied a noise threshold to further distinguish between non-gunfire noise and gunfire impulses.
* When WA conducted the solar analysis, they found that the dictabelt grassy knoll shot was a nearly perfect match for a test shot from the grassy knoll, which was fired from a position 8 feet west of the corner of the picket fence on the grassy knoll.
In the first sonar analysis comparison, done without the noise threshold, WA found that when the muzzle blast of the test shot was aligned with the first large impulse of the 145.15 shot—the grassy knoll shot—all 26 echoes of the test shot occurred within 1 millisecond of a corresponding impulse of the 145.15 shot.
In the second sonar analysis comparison, WA found that when they applied the noise threshold, the grassy knoll shot had 14 large impulses compared to the 12 large impulses of the test-shot pattern. Crucially, 10 of the 12 impulses in the test shot matched impulses in the grassy knoll shot to within 1 millisecond. This is an astounding correlation. Dr. Weiss explained:
* Dr. Barger explained the importance of the WA analysis:
* Actually, due to the fact that the two groups of HSCA acoustical experts worked separately, a math error arose in the calculation of the odds relating to the grassy knoll shot. The probability that the grassy knoll shot was the result of random noise was computed to be less than 5%, or less than 1 in 20, based mainly on a miscalculation of the value of p in the formula. The actual odds are even lower than WA calculated. Dr. Donald Thomas has demonstrated that they are actually only 1 in 100,000, or 100,000 to 1 against (http://jfklancer.com/pdf/Thomas.pdf). Put into percentage terms, the probability that chance produced the grassy knoll shot is 0.001%. To put it another way, the probability that the grassy knoll shot is a gunshot is 99.999%.
Interestingly, in their report, WA pointed out that they had been conservative in calculating the odds that chance had produced the matches between the grassy knoll shot's impulses and the test shot's echo patterns, and that the odds that chance had caused such a high degree of correlation were "considerably less than 5 percent":
* Revealingly, the NRC panel recognized that WA had assigned the wrong value for p in their calculations; however, the panel not only failed to tell their readers that WA had overestimated the odds that the grassy knoll shot was random noise, but they used erroneous assumptions in their own calculations to make it seem like there was a 22% chance that the grassy knoll shot was random noise.
Yes, in so doing, the NRC panel was admitting there was a 78% chance that the grassy knoll shot was a gunshot, but 78% is quite a bit lower than 95%+, and far lower than 99.999%.
There was no grassy knoll shot no matter how many times you attempt to look relevant on this subject. 57 years since the event and no physical evidence for a grassy knoll shot. None. Zero. Zilch. Who exactly is your audience? This is truly bewildering.
-
In my previous reply, I explained the timeline and nature of the HSCA acoustical analysis. However, I purposely did not go into much detail on the grassy knoll shot, because that would have made the reply about 50% longer, and it was already long enough. When you understand how Weiss and Aschkenasy (WA) confirmed the grassy knoll shot, you more fully understand the powerful nature of the acoustical evidence.
* The grassy knoll shot is the 145.15 shot, the third of the four shots that the HSCA acknowledged on the dictabelt recording. The BBN scientists noted that this was shot was aimed at JFK when the limousine was “near the limousine position seen in frame 313” (8 HSCA 6).
* The main reason that WA were asked to review the BBN analysis was that BBN said the grassy knoll shot had a certainty factor of only 50%. Everyone recognized that if the 145.15 shot was confirmed to be a shot from the grassy knoll, this would automatically prove that more than one gunman fired at JFK, since no one doubted that at least one shot was fired from behind, and since the sixth-floor gunman could not have fired a shot from the grassy knoll.
BBN said the three other shots had much higher certainty factors:
1st shot: 88% (based on three matches)
2nd shot: 88% (based on three matches)
4th shot: 75% (based on two matches)
* The third shot had a 50% certainty factor because it matched one test-firing shot from the grassy knoll but matched two test-firing shots from the TSBD. The grassy knoll match had a correlation coefficient of 0.8, a very high coefficient, whereas the two TSBD matches had a correlation coefficient of 0.7. Only five other matches of the 15 matches (really correlations) had a coefficient of 0.8. Based on this fact and on other factors, the BBN scientists concluded that the third shot came from the grassy knoll, but they knew that a more-refined analysis was needed to confirm this and to prove that the two TSBD matches were false matches.
The BBN scientists knew that the locations of the microphones in the test-firing caused false alarms/false matches:
They suspected that if they had used more microphones so that the microphones had been closer to each othe3r, the two TSBD matches on the third shot would not have occurred.
* WA realized that the problem was that the microphones in the test firing were spaced 18 feet apart. The 18-foot spacing was the reason that BBN applied a 6-millisecond acceptance window when determining matches.
* As WA explained in their testimony, they did not need to do another test firing in Dealey Plaza to solve the microphone-spacing problem. They knew they could do a computerized sonar analysis that would duplicate the conditions of closer microphone spacing and the resulting echo patterns. They wrote a sonar analysis program that simulated an echo pattern for 180 locations surrounding the location of the test microphone that gave the best match for the third dictabelt impulse pattern, i.e., the grassy knoll shot.
WA had written similar sonar analysis programs for the U.S. Navy—that was one of the reasons the Acoustical Society of America recommended them to the HSCA.
Significantly, the sonar analysis enabled WA to reduce the acceptance window for a match from 6 milliseconds down to 1 millisecond, a 500% narrower window, which vastly reduced the possibility of a false match. WA also applied a noise threshold to further distinguish between non-gunfire noise and gunfire impulses.
* When WA conducted the solar analysis, they found that the dictabelt grassy knoll shot was a practically perfect match for a simulated test-firing shot at a position 5 feet from the microphone position.
In the first sonar analysis comparison, done without the noise threshold, WA found that when the muzzle blast of the test shot was aligned with the first large impulse of the 145.15 shot—the grassy knoll shot—all 26 echoes of the test shot occurred within 1 millisecond of corresponding impulse of the 145.15 shot, an impressive correlation.
In the second sonar analysis comparison, WA found that when they applied the noise threshold, the grassy knoll shot had 14 large impulses compared to the 12 large impulses of the test-shot pattern. Crucially, 10 of the 12 impulses in the test shot matched impulses in the grassy knoll shot to within 1 millisecond. This is an astounding correlation. Dr. Weiss explained:
* Dr. Barger explained the importance of the WA analysis:
* Actually, due to the fact that the two groups of HSCA acoustical experts worked separately, a math error arose in the calculation of the odds relating to the grassy knoll shot. The probability that the grassy knoll shot was the result of random noise was computed to be less than 5%, or less than 1 in 20, based mainly on a miscalculation of the value of p in the formula. The odds are even lower than WA calculated. Dr. Donald Thomas has demonstrated that they are actually only 1 in 100,000, or 100,000 to 1 against (http://jfklancer.com/pdf/Thomas.pdf). To put it another way, there is a 99.999% chance that the grassy knoll shot is a gunshot.
* Revealingly, the NRC panel recognized that WA had assigned the wrong value for p in their calculations; however, the panel not only failed to tell their readers that WA had overestimated the odds that the grassy knoll shot was random noise, but they used erroneous assumptions in their own calculations to make it seem like there was a 22% chance that the grassy knoll shot was random noise.
Yes, in so doing, the NRC panel was admitting there was a 78% chance that the grassy knoll shot was a gunshot, but 78% is quite a bit lower than 95%+ (and far lower than 99.999%).
First of all, it sounds like Weiss and Aschkenasy (W&A) may have compared a lot of locations with 145.15 in the vicinity of the microphone 3 ( 4 ). Perhaps starting 15 feet up the street toward Houston, in a line of 10 feet across. And checked every foot as they went down Elm Street, until they got passed microphone 3 ( 4 ) by 15 feet. So, they might have checked, by computer, a grid of 31 by 11 locations or 341 locations. If there was that many, it might be a mathematical certainty that they would find an excellent correlation, with a hypothetical microphone location. One might not find an excellent correlation with the first of the 341 hypothetical microphone locations, or with the second, but it there might be a high chance one will found before one is done with all 341 hypothetical locations.
I have no idea the size of this array, but for the rest of this post, I will refer to it as the “31 x 11” array, to make it clear what array I am talking about.
Weiss and Aschkenasy (W&A) found a great correlation with the 1963 impulse at 145.15 and one of the Grassy Knoll test shots of 1978.
There were 12 test shots that were compared. 4 of them from the grassy knoll:
Test Shot 5: Rifle, fired at Target 2 (near z224)
Test Shot 8: Rifle, fired at Target 3 (near z313)
Test Shot 12: Rifle, fired at Target 4 (near Mt. Tague)
Test Shot 9: Pistol, fired at Target 3 (near z313)
W&A believe they can predict what the waveform, recorded by 3 ( 4 ) would look like from a certain location five feet away. Did they confirm that?
This can be done with running the calculations for a location where microphone 3 ( 3 ) was. And then comparing the calculated waveform with the real waveform that was recorded at 3 ( 3 ) with the same shot.
Question 1:
Did they confirm that their mathematical model would predict a waveform at 3 ( 1 ), 3 ( 2 ), 3 ( 3 ), 3 ( 5 ), 3 ( 6 ), 3 ( 7 )
by comparing
• A mathematical calculation of what a Grassy Knoll shot fired at Target 3 would look like at these six locations?
with:
• The real Grassy Knoll test shot fired at Target 3, recorded at those locations?
If their predictions, based on:
• The waveform recorded in 1978 for microphone 3 ( 4 )
• Running the calculations for the locations of 3 ( 1 ), 3 ( 2 ), 3 ( 3 ), 3 ( 5 ), 3 ( 6 ) and 3 ( 7 )
Do not match the recorded 1978 waveforms for what 3 ( 1 ), 3 ( 2 ), 3 ( 3 ), 3 ( 5 ), 3 ( 6 ) and 3 ( 7 ) actually recorded in 1978,
then one cannot put much confidence in the calculations for that spot that was 5 feet from 3 ( 4 ).
Question 2:
Which of these 4 test shots did W&A find the strong correlation with 145.15? Was it 5, 8, 12 or 9?
Question 3:
Did they make as an in-depth search, not just for one of the test shots but of all 4 Grassy Knoll test shots, to find every “Grassy Knoll” correlation they could, over this “31 x 11” array?
Question 4:
Did the make a really in-depth search, of all 12 test shots, to find every correlation they could over this “31 x 11” array?
It is important for to search for correlations, even if they are “impossible”, because they would contradict each other.
If one conducts the same procedure with all 12 test shots:
• and find no strong correlations, except for Test Shot # 8, at a spot 5 feet from 3 ( 4 ),
that is good.
• But finds a strong correlation for Test Shot # 8, at a spot 5 feet from 3 ( 4 ),
and finds a strong correlation for Test Shot # 3, at a spot 7 feet from 3 ( 4 ),
and finds a strong correlation for Test Shot # 11, at a spot 2 feet from 3 ( 4 ),
that is bad.
Finding correlations for shots fired from different positions at different targets strongly implies that one is just finding random correlations.
I should note, is that the best thing about the BBN tests, and compiling Exhibit F-367, is that they didn’t limit themselves to only the results that were possible. They could have searched for a correlation near 2 ( 5 ) and as soon as they find one, stop there. But they didn’t, they still searched for other correlations, and found correlations near 2 ( 5 ) for:
• A shot from the TSBD fired at Target 1 (near z155)
• A shot from the TSBD fired at Target 3 (near z313)
• A shot from the Grassy Knoll at Target 4 (Mr. Tague)
If they stopped after finding the first correlation, the data would have looked good. But by being more through, and checking all the other possibilities, they thoroughly test their procedure. Which was found suspect by the multiple and conflicting correlations. But it was good they checked for other “impossible” correlations.
I am concerned that W&A might not have done something similar.
* Actually, due to the fact that the two groups of HSCA acoustical experts worked separately, a math error arose in the calculation of the odds relating to the grassy knoll shot. The probability that the grassy knoll shot was the result of random noise was computed to be less than 5%, or less than 1 in 20, based mainly on a miscalculation of the value of p in the formula. The odds are even lower than WA calculated. Dr. Donald Thomas has demonstrated that they are actually only 1 in 100,000, or 100,000 to 1 against (http://jfklancer.com/pdf/Thomas.pdf). To put it another way, there is a 99.999% chance that the grassy knoll shot is a gunshot.
I must confess that I am a little skeptical that Barger, Weiss and Aschkenasy could have been so far off with their math. Instead of a 1 in 20 chance that the correlations could have been from chance, the odds were actually 1 in 100,000? Math errors of this magnitude are pretty rare for people who are good at math.
Question 5:
Do Dr. Barger, Dr. Weiss and Mr. Aschkenasy all agree with Dr. Thomas on this?
And it does not look good how much these calculations of the odds of these correlations being a result of just chance has changed wildly over the years. It has gone
• from 1 in 2 (BBN)
• to 1 in 20 (W&A)
• to 1 in 25 (Dr. Thomas correcting W&A)
• to 1 in 100,000 (Dr. Thomas correcting BBN, W&A and himself)
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It is interesting to note that when the BBN acoustical scientists began their analysis of the position of the motorcycle with the stuck mike, they did not know that the speed of the motorcycle matched the speed of the motorcade. They only realized the speeds matched after they asked the HSCA for the speed of the motorcade. We learn this from an interview with Dr. Scott Robinson, one of the BBN experts:
We didn’t know what the speed of the motorcade was. And he [Dr. Barger] called somebody at the select committee and asked them to tell him what the speed of the motorcade was. And they looked in their records and told him. And it turned out the speeds matched. And that’s when things got pretty convincing.
Recall, too, that when Weiss and Aschkenasy first heard the dictabelt recording, they doubted that it contained gunfire:
Mr. WEISS. We had no preconception as to what we were going to find. If anything, when we first heard the tape recording and first began to examine the data, our initial reaction was, somebody has got to be kidding; this can't be gunshots. But as we examined the data more carefully, subjected it to all the tests that we have described, the procedures that we have described, the results of the analyses themselves convinced us of where we were heading. Obviously, we did not have any plan or any objective other than to do the best we could to find out what really these data represent.
Mr. ASCHKENASY. If I may--
Mr. FITHIAN . Yes, Sir; go ahead.
Mr. ASCHKENASY. If I may say just one line, it's that the numbers could not be refuted. That was our problem. The numbers just came back again and again the same way, pointing only in one direction, as to what these findings were. There just didn't seem to be any way to make those numbers go away, no matter how hard we tried. (5 HSCA 593)
Finally, I stumbled across a great presentation on the acoustical evidence by Dr. Thomas that he gave in 2003. It is the most in-depth video on the subject that I have seen. It is 52 minutes long.
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Another point I should mention regarding Dr. Thomas’s claim that the 1963 impulse can be matched to a 1978 test shot, to a degree of 1 in 100,000 degree of certainty. These sorts of certainties require ideal conditions.
There was a wind blowing at the time of the assassination that gusted between 10 to 15 mph and the limousine was heading into this head wind. These estimates are based on the effects of the wind on the flags on the limousine and the clothes of the spectators, like Jean Hill and Mary Moorman.
Intuitively, to match a shot made in 1963 with a test shot made in 1978, to such fine precision, that one knew there was “Only a 1 in 100,000” chance the two waveforms were so identical by a fluke of luck, I would think one would need absolutely ideal conditions:
• Both recordings made by excellent equipment. We know this is not the case of the 1963 recording, recorded by a motorcycle with a stuck transmitter and recorded on the low quality Dictabelt, which was only designed to play back a limited number of times.
• Both microphones where in the exact same position we known almost certainly did not happen, because the microphones were about 15 feet apart. Indeed W&A calculated the closest microphone was still off of the motorcycle’s position by 5 feet.
• There was no wind for both recordings, or at least the wind was identical. As far as we know, this was not the case.
It is unbelievable to me, that a 10 to 15 mph wind would not affect the waveforms of a recorded shot enough to make it impossible to match it with a later test shot 15 years later to the probability of 1 in 100,000. To a layman like me, this sounds bogus. Even Weiss and Archkenasy never claimed this level of certainty.
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It is interesting to note that when the BBN acoustical scientists began their analysis of the position of the motorcycle with the stuck mike, they did not know that the speed of the motorcycle matched the speed of the motorcade. They only realized the speeds matched after they asked the HSCA for the speed of the motorcade. We learn this from an interview with Dr. Scott Robinson, one of the BBN experts:
Recall, too, that when Weiss and Aschkenasy first heard the dictabelt recording, they doubted that it contained gunfire:
Finally, I stumbled across a great presentation on the acoustical evidence by Dr. Thomas that he gave in 2003. It is the most in-depth video on the subject that I have seen. It is 52 minutes long.
None of this answer any of my questions from yesterday’s post.
W&A claimed they could calculate what the “shot” would have sounded like from any position near the microphone 3 ( 4 ), and found a good match about 5 five away.
Question 1:
Did they demonstrate that they really could do so? Did they calculate, solely form the 3 ( 4 ) recording, what the waveform would be if recorded at the 3 ( 3 ) position. And found that the calculated waveform matched with the 3 ( 3 ) recording just as well as the calculated waveform (for the position 5 feet from 3 ( 4 ) ) matched the 1963 waveform?
Question 2:
Which of the Test shots did they find match the 1963 waveform? I assume this was Test Shot # 8, the one fired with a rifle (and not a pistol), from the Grassy Knoll, at Target 3. But is this assumption correct?
Question 3:
Did they use the computer to look for correlations not just with Test Shot # 8 but all 12 Test shots?
If their procedure is bound to find strong correlations, because so many potential positions of the microphone are tested for, this will be revealed if strong correlations are also found for other test shots, fired at different targets or from the TSBD.
Question 4:
Do Dr. Barger, Dr. Weiss and Mr. Aschkenasy all agree with Dr. Thomas that they made a huge error in their calculations of the probability that these correlations could be may chance?
Not a 1 in 20 chance but a 1 in 100,000 chance. [/b]
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Errors in the HSCA report, as shown at:
https://www.archives.gov/research/jfk/select-committee-report/part-1b.html (https://www.archives.gov/research/jfk/select-committee-report/part-1b.html)
Of the 2,592 comparisons between the six sequences of impulses on the 1963 police dispatch tape and the sequences obtained during the acoustical reconstruction in August 1978, 15 had a sufficient number of matching points (a correlation coefficient of .6 or higher) to be considered significant.(33) The first and sixth sequence of impulses on the dispatch tape had no matches with a correlation coefficient over .5. The second sequence of impulses on the dispatch tape had four significant matches, the third sequence had five, the fourth sequence had three, and the fifth sequence had three.(34) Accordingly, impulses one and six on the dispatch tape did not pass the most rigorous acoustical test and were deemed not to have been caused by gunfire from the Texas School Book Depository or grassy knoll.(35) Additional analysis of the remaining four impulse sequences was still necessary before any of them could be considered as probably representing gunfire from the Texas School Book Depository or the grassy knoll.
This does not seem right. BBN’s Exhibit F-367 lists not six sequences of impulses on the 1963 police dispatch tape, but 7, as seen below:
http://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm (http://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm)
At:
136.20 low correlation of 0.5
137.70
139.27
140.32 low correlation of 0.6, rejected by BBN, accepted by Thomas
145.15
145.61
146.30 low correlation of 0.5
This causes another change. There were 12 test shots from 1978 that were compared with the 7 impulses from the 1963 recording. Each of the test shots were recorded on 36 microphones. So, all 12 test shots produced 36 * 12 or 432 recordings. This means the number of combinations of 1978 recordings which need to be comparted to the 7 1963 impulses is not 432 * 6 = 2,592 but is 432 * 7 = 3,024.
Plus, there is much confusion over how many correlations were found with the third, fourth, fifth and sixth impulses. I would guess some of this stemmed from their confusing F-367 chart, which should have listed the 139.27 – 3 ( 5 ) correlation with the other three 139.27 correlations.
It seems to me; this paragraph should state:
Of the 3,024 comparisons between the seven sequences of impulses on the 1963 police dispatch tape and the sequences obtained during the acoustical reconstruction in August 1978, 15 had a sufficient number of matching points (a correlation coefficient of .6 or higher) to be considered significant.(33) The first and seven sequence of impulses on the dispatch tape had no matches with a correlation coefficient over .5. The second sequence of impulses on the dispatch tape had four significant matches, the third sequence had four, the fourth sequence had one. the fifth sequence had three, and the sixth sequence had three.(34) Accordingly, impulses one and seven on the dispatch tape did not pass the most rigorous acoustical test and were deemed not to have been caused by gunfire from the Texas School Book Depository or grassy knoll.(35) Additional analysis of the remaining five impulse sequences was still necessary before any of them could be considered as probably representing gunfire from the Texas School Book Depository or the grassy knoll.
It does not seem to be the case that either the first impulse at 136.20 or the last impulse at 146.30 were rejected early and no comparison with any of the 1978 test shots was ever done. Because both show a correlation of 0.5 which shows that some comparisons were done for both the first and seventh impulse with the 1978 test data.
So, throughout the HSCA testimony and reports, all the phrases involving 2,592, like “2,592 comparisons” should have used the number 3,024.
This, of course, makes it even less likely that the BBN completed a thorough check of all 3,024 possible combinations of 1963 Dictabelt impulses with the 1978 test impulses within 10 days.
And finally, so many errors in one paragraph of the final report to the HSCA, does not reflect well on BBN. These errors are not on some minor periphery issue but on the core of their case:
• The number of impulses on the 1963 Dictabelt tape in the area of interest.
• The number of combinations of “1963 impulses” with “1978 impulses”
• Which impulses were rejected due to no correlation above 0.5 being found
• Number of correlations found with each impulse.
They had over three months to get these details right, which I found and corrected in two hours.
Just retyping the Table on F-367, with each correlation in the proper order, may have caused many of these obvious errors to have been spotted and corrected before the final report was submitted.
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There was no grassy knoll shot no matter how many times you attempt to look relevant on this subject. 57 years since the event and no physical evidence for a grassy knoll shot. None. Zero. Zilch. Who exactly is your audience? This is truly bewildering.
You are not to be taken seriously. The dictabelt recording is hard physical evidence of a grassy knoll shot. Even the NRC panel, after monkeying with the calculations as far as they dared, conceded that there was a 78% probability that the third impulse pattern on the police tape was not produced by random/non-gunfire noise. After spending over a year combing through the BBN and WA reports, the NRC panel did not lay a finger on the essential components of the acoustical evidence.
And, to answer someone else's question, yes, Dr. Barger agrees with Dr. Thomas's finding that the odds that random noise caused the grassy knoll gunshot on the police tape are 1 in 100,000. Dr. Thomas first brought this to light in his famous 2001 article in the peer-reviewed criminal science journal Science & Justice, and Dr. Barger proof-read that article (as did several other scholars). In the article, Dr. Thomas devoted two pages to explaining why and how WA's "5% or less" probability of chance was actually far too high. Here is the 2001 article:
http://www.jfklancer.com/pdf/Thomas.pdf
Dr. Thomas goes into much more detail on this issue in his book Hear No Evil, and he wrote the chapters on the acoustical evidence in close consultation with Dr. Barger. Dr. Thomas spends seven pages explaining the various odds calculations and explaining why the odds that chance caused the gunshot impulses are far more remote than "5% or less" (pp. 625-632).
And, we need to keep in mind that WA specified in their report that their calculation of "5% or less" odds was actually "highly conservative" because they did not factor in the fact that if the gunshot impulse patterns are non-gunshot sounds, they could have also occurred during 190-millisecond timeframe between the two intervals when echoes are seen on the police tape:
The high degree of correlation between the impulse and echo sequences does not preclude the possibility that the impulses were not the sounds of a gunshot. It is conceivable that a sequence of impulse sounds, derived from non-gunshot sources, was generated with time spacings that, by chance, corresponded within one one-thousandth of a second to those of echoes of a gunshot fired from the grassy knoll. However, the probability of such a chance occurrence is about 5 percent. This calculation represents a highly conservative point of view, since it assumes that impulses can occur only in the two intervals in which echoes were observed to occur, these being the echo-delay range from 0 to 85 milliseconds and the range from 275 to 370 milliseconds. However, if the impulses in the DPD recording were not the echoes of a gunshot, they could also have occurred in the 190-millisecond timespan that separated these two intervals. Taking this timespan into account, the probability becomes considerably less than 5 percent that the match between the recorded impulses and the predicted echoes occurred by chance. (8 HSCA 32)
This observation is almost always ignored in articles and books that discuss the acoustical evidence.
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And, to answer someone else's question, yes, Dr. Barger agrees with Dr. Thomas's finding that the odds that random noise caused the grassy knoll gunshot on the police tape are 1 in 100,000. Dr. Thomas first brought this to light in his famous 2001 article in the peer-reviewed criminal science journal Science & Justice, and Dr. Barger proof-read that article (as did several other scholars). In the article, Dr. Thomas devoted two pages to explaining why and how WA's "5% or less" probability of chance was actually far too high. Here is the 2001 article:
http://www.jfklancer.com/pdf/Thomas.pdf
Yes, but it was Dr. Weiss and Mr. Aschkenasy who made the original calculations. Do either of them agree with Dr. Thomas, that an error was made in calculating “p” resulting in a false estimate of the W&A correlation being a result of chance as 1 in 20, when the correct calculation was 1 in 100,000.
And, again, I am skeptical:
• That W&A could have made such a huge error.
And:
• It would be possible to make such a strong correlation, even if this is a recording of the Grassy Knoll shooter, given the variables that would be impossible to replicate precisely, like the exact speed of the wind that was between 10 to 15 mph at that moment. Some correlation could be found. But one that matches so perfectly, regardless of how the wind was blowing in 1963 and in 1978? It sounds implausible.
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You are not to be taken seriously. The dictabelt recording is hard physical evidence of a grassy knoll shot. Even the NRC panel, after monkeying with the calculations as far as they dared, conceded that there was a 78% probability that the third impulse pattern on the police tape was not produced by random/non-gunfire noise. After spending over a year combing through the BBN and WA reports, the NRC panel did not lay a finger on the essential components of the acoustical evidence.
And, to answer someone else's question, yes, Dr. Barger agrees with Dr. Thomas's finding that the odds that random noise caused the grassy knoll gunshot on the police tape are 1 in 100,000. Dr. Thomas first brought this to light in his famous 2001 article in the peer-reviewed criminal science journal Science & Justice, and Dr. Barger proof-read that article (as did several other scholars). In the article, Dr. Thomas devoted two pages to explaining why and how WA's "5% or less" probability of chance was actually far too high. Here is the 2001 article:
http://www.jfklancer.com/pdf/Thomas.pdf
Dr. Thomas goes into much more detail on this issue in his book Hear No Evil, and he wrote the chapters on the acoustical evidence in close consultation with Dr. Barger. Dr. Thomas spends seven pages explaining the various odds calculations and explaining why the odds that chance caused the gunshot impulses are far more remote than "5% or less" (pp. 625-632).
And, we need to keep in mind that WA specified in their report that their calculation of "5% or less" odds was actually "highly conservative" because they did not factor in the fact that if the gunshot impulse patterns are non-gunshot sounds, they could have also occurred during 190-millisecond timeframe between the two intervals when echoes are seen on the police tape:
This observation is almost always ignored in articles and books that discuss the acoustical evidence.
I am mostly interested in the comments of Dr. Weiss and Mr. Aschkenasy on Dr. Thomas’s corrections on the probability from 1 in 20 to 1 in 100,000, since it was Weiss and Aschkenasy calculations that he was correcting.
Question:
But where, exactly, is there a link to Dr. Barger approving of Dr. Thomas’s 1 in 100,000 calculations over that of Weiss and Aschkenasy’s 1 in 20?
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Below are a few excerpts from Dr. Thomas's book Hear No Evil, from the section on the odds that the gunshot impulses on the dictabelt tape are the result of random/non-gunfire noise:
For the sake of argument let us assume that it really is plausible that within moments of President Kennedy being assassinated a burst of static (perhaps cosmic particles from some supernova, or an eruption on the sun, or a thunderclap in the distance) had occurred, and that these static clusters had given rise to separate patterns that just happened to mimic the echo patterns of three gunshots from the Texas School Book Depository, one gunshot from nearby, and one from the grassy knoll, if recorded over a microphone traveling north on Houston Street then West on Elm Street at 11 mph when the air temperature was 65 degrees F.
Of course the NRC panel never mentioned that there was such order in the data, but accepting that such a scenario is plausible, what are the statistical chances of it happening? The HSCA experts calculated that just the grassy knoll pattern was likely to arise by chance in no more than about five percent of random patterns. The NRC panel claimed that the HSCA consultants had underestimated the odds because of computational errors. One of the computational "errors" alleged by the NRC report in the calculation of the 5 percent odds was as follows:
"The calculation of 0.053 involved some further errors. On page 75, the BRSW calculations claim that 12 of 22 predicted echoes were loud enough to exceed a threshold. It seems that 22 should be 26."
Yes, it should have been 26. The BBN report was written before Weiss and Aschkenasy had completed and written their analysis. At the time of their testimony in December 1979, Weiss and Aschkenasy had identified only 22 echoes.37 They eventually identified 26 echoes from 22 structures. The deception on the part of the NRC panel was that neither value, 22 nor 26, entered into the probability calculations. The NRC panel exploited the different statements by the different laboratories, juxtaposing the discrepancy with their own claim that the 0.053 calculation was wrong, to make it appear that BBN had made a computational error. This was the sort of trickery that the NRC panel engaged in to discredit the acoustical evidence. . . .
Thus, the number set that BBN used to begin their analysis, the numbers that would be plugged into the probability formula, was {45, 14, 12, 9}. The calculated probability of this number set occurring by chance is 3.13 x 10(-4) and was so reported by BBN. . . .
But, because of using the incorrect values for M and i, BBN had grossly overestimated the probability that a random burst of noise could have matched the test pattern. This was obviously an honest mistake because the error worked against their own conclusion by increasing the probability of coincidence by chance. It is interesting that the NRC panel caught this error and knew that the correct number of time slots was 90 and not 45. It proves that they did understand that the 190-millisecond gap between the two 90 millisecond bursts occurred in the middle of the impulse pattern and were not two completely separate patterns as they had asserted in their critique of the HSCA analysis. . . .
The NRC panel eliminated the erroneous adjustment for the M value by BBN, but, failed to recognize that Weiss & Aschkenasy had already made the adjustment for the alignment of the muzzle blast with the first impulse. Just putting back one for the overt error in the deduction for this alignment gives a data set of {84, 6, 5, 2}. The probability of this coincidence set is 3.7 x 10(-2), or about 3.7 percent. Even better than Weiss and Aschkenasy's original five percent!
The most appropriate estimate of the true probability would assign two degrees of freedom for the motorcycle location, one for shooter location, one for the alignment of the muzzle blast, and eliminate one pair of echoes and their coincidence (from pairs 19 and 20), giving a final number set of {86, 10, 8, 6} which calculates to 1.12 x 10(-5), or, 100,000 to one, against. Thus, one must conclude, on statistical grounds, that the Dallas Police tape contains
a sound impulse pattern which resembles the echo delay pattern of a gunshot from the grassy knoll to a degree unlikely to arise from a chance array of radio noises. (Hear No Evil, pp. 625-626, 628-629, 632)
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Below are a few excerpts from Dr. Thomas's book Hear No Evil, from the section on the odds that the gunshot impulses on the dictabelt tape are the result of random/non-gunfire noise:
Quote from Dr. Thomas:
For the sake of argument let us assume that it really is plausible that within moments of President Kennedy being assassinated a burst of static (perhaps cosmic particles from some supernova, or an eruption on the sun, or a thunderclap in the distance) had occurred,
Or perhaps as a result of cross-talk from Channel 2. One of the “shots” (at 145.15, the z304 or z313 “shot”) corresponds with the spoken phrase “Hold everything secure”, with the “shot” occurring at the same instant of the hard “K” of “secure”.
http://mcadams.posc.mu.edu/odell/ (http://mcadams.posc.mu.edu/odell/)
Quote from Michael O’Dell:
The "single loud click" near 144 sec. is unmistakable and marks the time when the "hold everything secure" phrase becomes audible. By using the scale on the Fig. 5 spectrogram and measuring the distance between the 144 mark and the click I determined that the click occurs at 144.05. BRSW's suspected grassy knoll shot was found on the same recording at 145.15 (31). WA adjusted the beginning time of the impulse pattern they studied by about 0.2 seconds, putting it at 144.95 (32). The beginning of WA's pattern is therefore about 0.9 seconds after the loud click. The audio software allows me to place markers and listen to sections between markers. By putting a marker at 0.9 seconds after the click, and listening to regions before and after the marker it is clear that the marker coincides with the "K" sound in the second syllable of the word "secure".
Quote from Dr. Thomas:
and that these static clusters had given rise to separate patterns that just happened to mimic the echo patterns of three gunshots from the Texas School Book Depository, one gunshot from nearby, and one from the grassy knoll, if recorded over a microphone traveling north on Houston Street then West on Elm Street at 11 mph when the air temperature was 65 degrees F.
The problem is that three of the four to five shots mimicked both a shot from the TSBD and a shot from the Grassy Knoll. That is, the same shot mimicked both. Clearly, an example of finding high probability random matchups. Real valid matchups would involve a shot mimicking a shot from either the TSBD or the Grassy Knoll, but not both.
Quote from Dr. Thomas:
Of course the NRC panel never mentioned that there was such order in the data, but accepting that such a scenario is plausible, what are the statistical chances of it happening? The HSCA experts calculated that just the grassy knoll pattern was likely to arise by chance in no more than about five percent of random patterns. The NRC panel claimed that the HSCA consultants had underestimated the odds because of computational errors. One of the computational "errors" alleged by the NRC report in the calculation of the 5 percent odds was as follows:
"The calculation of 0.053 involved some further errors. On page 75, the BRSW calculations claim that 12 of 22 predicted echoes were loud enough to exceed a threshold. It seems that 22 should be 26."
Yes, it should have been 26. The BBN report was written before Weiss and Aschkenasy had completed and written their analysis. At the time of their testimony in December 1979, Weiss and Aschkenasy had identified only 22 echoes.37 They eventually identified 26 echoes from 22 structures. The deception on the part of the NRC panel was that neither value, 22 nor 26, entered into the probability calculations. The NRC panel exploited the different statements by the different laboratories, juxtaposing the discrepancy with their own claim that the 0.053 calculation was wrong, to make it appear that BBN had made a computational error. This was the sort of trickery that the NRC panel engaged in to discredit the acoustical evidence. . . .
Thus, the number set that BBN used to begin their analysis, the numbers that would be plugged into the probability formula, was {45, 14, 12, 9}. The calculated probability of this number set occurring by chance is 3.13 x 10(-4) and was so reported by BBN. . . .
But, because of using the incorrect values for M and i, BBN had grossly overestimated the probability that a random burst of noise could have matched the test pattern. This was obviously an honest mistake because the error worked against their own conclusion by increasing the probability of coincidence by chance. It is interesting that the NRC panel caught this error and knew that the correct number of time slots was 90 and not 45. It proves that they did understand that the 190-millisecond gap between the two 90 millisecond bursts occurred in the middle of the impulse pattern and were not two completely separate patterns as they had asserted in their critique of the HSCA analysis. . . .
The NRC panel eliminated the erroneous adjustment for the M value by BBN, but, failed to recognize that Weiss & Aschkenasy had already made the adjustment for the alignment of the muzzle blast with the first impulse. Just putting back one for the overt error in the deduction for this alignment gives a data set of {84, 6, 5, 2}. The probability of this coincidence set is 3.7 x 10(-2), or about 3.7 percent. Even better than Weiss and Aschkenasy's original five percent!
The most appropriate estimate of the true probability would assign two degrees of freedom for the motorcycle location, one for shooter location, one for the alignment of the muzzle blast, and eliminate one pair of echoes and their coincidence (from pairs 19 and 20), giving a final number set of {86, 10, 8, 6} which calculates to 1.12 x 10(-5), or, 100,000 to one, against. Thus, one must conclude, on statistical grounds, that the Dallas Police tape contains
a sound impulse pattern which resembles the echo delay pattern of a gunshot from the grassy knoll to a degree unlikely to arise from a chance array of radio noises. (Hear No Evil, pp. 625-626, 628-629,
Mr. Griffith claims that this 1 in 100,000 event has been supported by Dr. Barger. But has not provided any citation to support this. Nor does it appear that Dr. Weiss and Mr. Aschkenasy has supported the claim that their 1 in 20 event should actually be a 1 in 100,000 event. This claim appears to be Dr. Thomas’s alone.
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Quote from Dr. Thomas:
Or perhaps as a result of cross-talk from Channel 2. One of the “shots” (at 145.15, the z304 or z313 “shot”) corresponds with the spoken phrase “Hold everything secure”, with the “shot” occurring at the same instant of the hard “K” of “secure”.
http://mcadams.posc.mu.edu/odell/ (http://mcadams.posc.mu.edu/odell/)
Quote from Michael O’Dell:
This stuff again??? If you would read Dr. Thomas's chapters on the acoustical evidence, you would know that Dr. Thomas has refuted O'Dell's arguments.
Again--I keep having to say "again" because you keep ignoring refutations of your arguments--there are five other time indicators on the police tape that show the gunshot impulses were recorded during the assassination, but you keep dismissing them and clinging for dear life onto Decker's "hold everything" crosstalk, even though it has the largest time offset of any crosstalk event.
Anyone who claims that the dictabelt's gunshot impulse patterns are not assassination gunfire needs to explain the powerful and intricate correlations between the dictabelt's gunshot impulse patterns and the patterns of shots fired in the Dealey Plaza test firing. They also need to explain the fact that N-waves and muzzle blasts occur on the dictabelt recording in the correct order and interval, and that these phenomena and windshield distortion occur on the tape when they should and do not occur when they should not. If the tape contains no assassination gunfire, then all of these incredible correlations must be unbelievable, mind-bogglingly improbable coincidences, the odds against which would probably be along the lines of 1 zillion to 1.
Quote from Dr. Thomas:
The problem is that three of the four to five shots mimicked both a shot from the TSBD and a shot from the Grassy Knoll. That is, the same shot mimicked both. Clearly, an example of finding high probability random matchups. Real valid matchups would involve a shot mimicking a shot from either the TSBD or the Grassy Knoll, but not both.
One, your comments show you don't know what you're talking about. Two, due to the placement of the microphones and the shooting locations in the test firing, it is not a bit surprising that some false matches occurred, and Dr. Barger discussed this in his testimony. Three, the WA sonar analysis destroyed the false-match argument for the grassy knoll shot.
Quote from Dr. Thomas:
Mr. Griffith claims that this 1 in 100,000 event has been supported by Dr. Barger. But has not provided any citation to support this. Nor does it appear that Dr. Weiss and Mr. Aschkenasy has supported the claim that their 1 in 20 event should actually be a 1 in 100,000 event. This claim appears to be Dr. Thomas’s alone.
This is a good example of how you twist and mislead. As is mentioned in the article itself, Dr. Barger proof-read the article in which Dr. Thomas first discussed the errors that BBN and WA made in some of the values they assigned in their probability calculations, all of which errors caused WA to vastly over-estimate the probability that the grassy knoll gunshot impulse pattern was caused by non-gunfire noise. They did not make any actual calculation errors, but their calculations were overly conservative because some of the values they assigned in the calculations were incorrect.
I repeat: Dr. Barger proof-read Dr. Thomas's article--the fact that he did so is mentioned in the article. And that article explains in some detail why the correct odds against chance for the grassy knoll shot are 100,000 to 1.
Plus, as I've mentioned, Dr. Barger and Dr. Thomas are good friends, and Dr. Thomas consulted with Dr. Barger extensively when he wrote the acoustics chapters in Hear No Evil.
As for Weiss and Aschkenasy, I have no information on their views on Dr. Thomas's calculations, although I am sure they agree with them if they have seen them, since the calculations can be verified by anyone who knows math well enough to do so. I would also note that WA said in their report that their "1 in 20 or less" odds were "highly conservative" and that the actual odds were much lower ("considerably less"). I notice you keep ignoring this fact.
You guys are still just dancing around the essential components of the acoustical evidence. No amount of obfuscation and diversion can change the fact that there are five impulse patterns on the dictabelt recording that match the impulse patterns of test-firing shots, and match them within windows of 6 milliseconds and 1 millisecond, and match them in the correct locational order. The odds against these impulses matching in the correct locational order by chance are 1 in 125 (i.e., less than 1%). Nor can any amount of evasion change the fact that patterns of N-waves, muzzle blasts, and windshield distortion occur on the dictabelt recording when they should and do not occur when they should not, and the fact that the WA sonar analysis proved beyond any reasonable doubt that the grassy knoll gunshot impulse pattern is in fact gunfire.
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This stuff again??? If you would read Dr. Thomas's chapters on the acoustical evidence, you would know that Dr. Thomas has refuted O'Dell's arguments.
O’Dell has refuted Dr. Thomas’s arguments.
Again--I keep having to say "again" because you keep ignoring refutations of your arguments--there are five other time indicators on the police tape that show the gunshot impulses were recorded during the assassination, but you keep dismissing them and clinging for dear life onto Decker's "hold everything" crosstalk, even though it has the largest time offset of any crosstalk event.
I am bringing up a different subject. Do you deny that “Hold everything secure” occurs at 145.15? Isn’t it possible that the “gunshot” at 145.15 is not a gunshot, or formed from cosmic rays, but is formed from a voice recorded by crosstalk from Channel 2 saying “Hold everything secure”, which the BBN failed to recognize as a voice?
If you deny “Hold everything is secure” is recorded there, where is it recorded? At 50.0? At 200.0? Where?
Anyone who claims that the dictabelt's gunshot impulse patterns are not assassination gunfire needs to explain the powerful and intricate correlations between the dictabelt's gunshot impulse patterns and the patterns of shots fired in the Dealey Plaza test firing. They also need to explain the fact that N-waves and muzzle blasts occur on the dictabelt recording in the correct order and interval, and that these phenomena and windshield distortion occur on the tape when they should and do not occur when they should not. If the tape contains no assassination gunfire, then all of these incredible correlations must be unbelievable, mind-bogglingly improbable coincidences, the odds against which would probably be along the lines of 1 zillion to 1.
The explanation for correct order and interval has been explained by me before and is explained again later in this post.
One, your comments show you don't know what you're talking about. Two, due to the placement of the microphones and the shooting locations in the test firing, it is not a bit surprising that some false matches occurred, and Dr. Barger discussed this in his testimony. Three, the WA sonar analysis destroyed the false-match argument for the grassy knoll shot.
This is a good example of how you twist and mislead. As is mentioned in the article itself, Dr. Barger proof-read the article in which Dr. Thomas first discussed the errors that BBN and WA made in some of the values they assigned in their probability calculations, all of which errors caused WA to vastly over-estimate the probability that the grassy knoll gunshot impulse pattern was caused by non-gunfire noise. They did not make any actual calculation errors, but their calculations were overly conservative because some of the values they assigned in the calculations were incorrect.
I repeat: Dr. Barger proof-read Dr. Thomas's article--the fact that he did so is mentioned in the article. And that article explains in some detail why the correct odds against chance for the grassy knoll shot are 100,000 to 1.
Plus, as I've mentioned, Dr. Barger and Dr. Thomas are good friends, and Dr. Thomas consulted with Dr. Barger extensively when he wrote the acoustics chapters in Hear No Evil.
Dr. Barger has never stated that the correct probability is not 1 in 20, but 1 in 100,000. However, what Dr. Barger has done is:
• Dr. Barger proof-read the article that Dr. Thomas first discussed the errors that BBN and WA made in some of the values they assigned in their probability calculations,
• Dr. Thomas and Dr. Barger are good friends
• Dr. Thomas and Dr. Barger consulted when Dr. Thomas wrote his book
The fact that Dr. Barger proof-read the article of Dr. Thomas’s does not tell us that he agreed with everything in it. He might have agreed with this 1 in 100,000 probability. Or he might disagree with it. And tried to convince Dr. Thomas that this is wrong. But failed to do so. And Dr. Thomas left it in his article. We simply don’t know, on the basis of “Dr. Barger proof-read the article”.
If Dr. Barger agrees with this 1 in 100,000 probability estimate, it is exceedingly strange that he chooses to stay silent on this. Dr. Barger, Dr. Weiss and Mr. Aschkenasy got slapped down by the National Academy of Sciences back in 1982. Their work was reviewed and rejected by an elite panel of scientists, including past and future Nobel Prize winners. This is an embarrassing rebuke. Dr. Barger would seize on any strong evidence, any strong argument, to show that he was right all along.
If he agreed with Dr. Thomas on this, he would be making his views known in an unmistakable manner, and not hold these views close to his chest. I think I can infer that while Dr. Barger may be friends with Dr. Thomas, he does hold some serious misgivings about this 1 in 100,000 probability estimate.
This is about as believable as a claim that the original “discovers” of Cold Fusion, who published their work saying that it appeared that Cold Fusion was real, had their work rejected by the Scientific community, subsequently discovered not just new support but proof of Cold Fusion, but decide to say nothing to anyone. Yeah, I can believe a story like that.
As for Weiss and Aschkenasy, I have no information on their views on Dr. Thomas's calculations, although I am sure they agree with them if they have seen them, since the calculations can be verified by anyone who knows math well enough to do so. I would also note that WA said in their report that their "1 in 20 or less" odds were "highly conservative" and that the actual odds were much lower ("considerably less"). I notice you keep ignoring this fact.
Again, Dr. Weiss and Mr. Aschkenasy would not stay silent on this issue, if they thought Dr. Thomas discovered the ultimate vindication of their work in 1978, which was rejected by the National Academy of Sciences.
The bottom line is you cannot site any support from Dr. Barger, Dr. Weiss or Mr. Aschkenasy, that they agree with Dr. Thomas’s 1 in 100,000 claim. You basically figure that because Dr. Barger and Dr. Thomas are such good friends, then surely, he must. But for some strange reason, is totally silent on this question. While still not silent about his standing behind his 1978 Acoustic work.
You guys are still just dancing around the essential components of the acoustical evidence. No amount of obfuscation and diversion can change the fact that there are five impulse patterns on the dictabelt recording that match the impulse patterns of test-firing shots, and match them within windows of 6 milliseconds and 1 millisecond, and match them in the correct locational order. The odds against these impulses matching in the correct locational order by chance are 1 in 125 (i.e., less than 1%). Nor can any amount of evasion change the fact that patterns of N-waves, muzzle blasts, and windshield distortion occur on the dictabelt recording when they should and do not occur when they should not, and the fact that the WA sonar analysis proved beyond any reasonable doubt that the grassy knoll gunshot impulse pattern is in fact gunfire.
1 in 125? We are not calculating the volume of a cube with edge lengths of 5 feet here. Again, as I explained before. The number of ways of ordering all 5 members of a set is not 125 (5 to the third power or 5 ** 3). It is 5 Factorial, which can be expressed as 5!. That is 5 * 4 * 3 * 2 * 1 = 120.
There are 5 candidates to chose as the first number. After it is chosen, there are only 4 candidates for the second. After the first two are chosen, there are 3 candidates for the third. And so on. Hence, the number of ways of ordering all 5 members of a set is 5 * 4 * 3 * 2 * 1. A good high school Algebra 1 student should not miss this.
So, there are not 125 but 120 ways of arranging the shots in “the correct locational order”.
High school got out a long time ago. When are you going to start to get this right?
There is only a 1 in 120 chance that the ‘motorcycle location’ would come up ordered this way. You don’t think this came about through chance. And I don’t either.
I think BBN did something like the following in the last 10 days of August 1978:
Maybe after finding the second shot around microphone 2 ( 6 ) through 3 ( 5 ), which they assumed 2 ( 6 ) was the correct microphone, they didn’t start searching through the microphones at random, but started searching for where the first shot might have been recorded, before microphone 2 ( 6 ).
Maybe after finding the first shot around microphone 2 ( 5 ) through 2 ( 6 ), they didn’t start searching through the microphones at random, but started searching for where the third shot might have been recorded, after microphone 2 ( 6 ).
Maybe after finding the third shot around microphone 2 ( 11 ), they didn’t start searching through the microphones at random, but started searching for where the fourth shot might have been recorded, after microphone 2 ( 11 ).
Maybe after finding the fourth shot around microphone 3 ( 4 ), they didn’t start searching through the microphones at random, but started searching for where the fourth shot might have been recorded, after microphone 3 ( 4 ).
If this method was followed, to avoid searching through all 3,024 test recordings from 1978, which might not have even been possible in ten days, they would naturally find all the shots in the correct order. They’re not going to find the last shot before microphone 2 ( 5 ), because they never searched for it there.
And it was well known that the motorcade speed averaged 11 mph. It was explicitly stated that in the Warren Commission. I don’t care if Dr. Barger’s old memories don’t recall knowing that in August of 1978. He or someone on his team may well have known that. One can get a rough idea of the speed of the limousine just be watching the Zapruder film. And they could use that information on where to look for correlations first. Like for looking for the first shot not anywhere before microphone 2 ( 6 ) but at locations consistent with a 11-mph speed. This would account for the correct order and spacing of all five shots found.
My scenario explains why they got random results for correlations with the source of the shots (TSBD or KNOLL), random results for correlations with the location of the target ( Target 1, 2, 3, 4 ) but non-random results for the location of the motorcycle.
You guys are still just dancing around the essential components of the acoustical evidence. No amount of obfuscation and diversion can change the fact that there are five impulse patterns on the dictabelt recording that match the impulse patterns of test-firing shots, . . .
Yes. The shot at 137.70 matches the impulse pattern of a 1978 test shot from the TSBD. And also matches a 1978 test shot from the Grassy Knoll.
The shot at 139.27 matches the impulse pattern of a 1978 test shot from the TSBD. And also matches a 1978 test shot from the Grassy Knoll.
The shot at 145.15 matches the impulse pattern of a 1978 test shot from the TSBD. And also matches a 1978 test shot from the Grassy Knoll.
So, the fact that the Dictabelt recording “matches up” with the recordings of the 1978 test firings seem meaningless. It is abundantly clear that such a match up can occur through random luck alone, and seems almost inevitable if one checks a for a dozen or so possible correlations.
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It's pretty obvious that at some point in time the bug professor became a fanatic CT advocate and fanboy Griffith is now parroting anything and everything published by Dr. Thomas.
The longer sales pitch contained the same dishonest claim of matching "all five" ignoring, and not even mentioning, the so-called false positives (no, I'm not going to transcribe the BS he's proffering) at around 25:00 onward.
Unfortunately 'parroting' doesn't mean 'understanding' so there will be no explanation of the 1 in 100.000 claim by fanboy Griffith, but it's useful to check Appendix C in the Barger report which explains why even detecting possible gunshots is a statistical exercise in itself: we're looking for spikes in a sea of noise, which BTW is assumed to be random, which we don't actually know.
The quality of the tape was so bad they had to set the threshold at .6 so their 'detector' was more like a 'dredger'.
As for the process in regard to time taken and the amount of patterns checked raised by Joe Elliott, I'll bet they initially spent days dialing in the threshold (lowering it progressively) as they realized how bad that tape was.
Your comments are comically wrong, once again. You still have not answered my question about why you choose the Decker crosstalk as your time indicator over the Fisher crosstalk, the two Curry transmissions made in Dealey Plaza, and the two dispatcher time notations.
Now, of course, we both know that you cling to the Decker crosstalk because otherwise you would have to explain the amazing and intricate correlations between the dictabelt's impulse patterns and the patterns of at least four of the Dealey Plaza test-firing shots.
You'd have to explain why five of the dictabelt impulse patterns match five of the test-firing shots in the correct locational order and in the correct average rate of speed. The odds that five impulses would match in the correct locational order alone are 1 in 125, less than 1%.
You'd have to explain the N-wave and muzzle-blast patterns and the fact that they occur in the correct order and interval in the dictabelt impulse patterns.
You'd have to explain why windshield distortion occurs when it should and does not occur when it should not in the dictabelt impulse patterns.
You'd have to explain the WA sonar analysis of the grassy knoll impulse pattern, which removed the false-match problem, reduced the acceptance window from 6 milliseconds to 1 millisecond, and reduced the microphone spacing from 18 feet to 1 foot.
You know you can't explain these things (the NRC panel could not explain them either), so you cling to the Decker crosstalk and use it as your excuse for not dealing with the actual acoustical evidence.
You and Joe Elliott will always find some excuse, no matter how lame, to avoid admitting that the acoustical evidence is valid and solid. Just look at Elliott's last sad, labored, and evasive reply about Dr. Thomas's finding that the actual odds that chance caused the grassy knoll shot are 100,000 to 1 against. You guys will continue to deny the acoustical evidence because you don't want to believe it, because if you did, you would have to abandon your entire theory of the assassination.
I'm curious: Most of us in the research community know that Dr. Josiah Thompson's upcoming new book, Last Second in Dallas, will include a detailed defense and confirmation of the acoustical evidence, and that he has been working with Dr. Barger on the acoustics evidence for years. The book will include information on a new acoustical test that was conducted. The book will be released on December 3, less than eight weeks from now. Do you plan on reading it?
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You'd have to explain why five of the dictabelt impulse patterns match five of the test-firing shots in the correct locational order and in the correct average rate of speed. The odds that five impulses would match in the correct locational order alone are 1 in 125, less than 1%.
Back to the class room Mr. 1-in-125. It is 1 in 5*4*3*2*1 or 1-in-120. Go read a basic book on algebra which has a probability section.
You'd have to explain the N-wave and muzzle-blast patterns and the fact that they occur in the correct order and interval in the dictabelt impulse patterns.
Already explained, many times. Sampling bias.
You'd have to explain why windshield distortion occurs when it should and does not occur when it should not in the dictabelt impulse patterns.
It’s not clear there shouldn’t always be distortion in any of the BBN motorcycle positions, either from the windshield or the torso on the rider.
You and Joe Elliott will always find some excuse, no matter how lame, to avoid admitting that the acoustical evidence is valid and solid. Just look at Elliott's last sad, labored, and evasive reply about Dr. Thomas's finding that the actual odds that chance caused the grassy knoll shot are 100,000 to 1 against. You guys will continue to deny the acoustical evidence because you don't want to believe it, because if you did, you would have to abandon your entire theory of the assassination.
And yet you can find no expert who endorses Dr. Thomas’s 1-in-100,000 claim Not even from his close friends.
I'm curious: Most of us in the research community know that Dr. Josiah Thompson's upcoming new book, Last Second in Dallas, will include a detailed defense and confirmation of the acoustical evidence, and that he has been working with Dr. Barger on the acoustics evidence for years. The book will include information on a new acoustical test that was conducted. The book will be released on December 3, less than eight weeks from now. Do you plan on reading it?
Mr. 1-in-125 is in the research community?
Plan on reading it?
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Back to the class room Mr. 1-in-125. It is 1 in 5*4*3*2*1 or 1-in-120. Go read a basic book on algebra which has a probability section.
Oh, dear! Yes, there are 120 ways, not 125 ways, to sequence five events. So let's see what difference this makes in the odds: 1 in 120 is 0.83% vs. 0.8% for 1 in 125, which means the probability that the locational order in the matches is *not* the result of chance is 99.17% instead of 99.20%. I'll take 99.17%. No problem.
So, how do you explain the locational order in the matches, since the odds that such matches could be mere coincidence are 120 to 1 against?
Already explained, many times. Sampling bias.
LOL! What utter hogwash. What "sampling bias"? There was no "sampling bias." The BBN scientists examined every peak and line of every second of the dictabelt tape. You've been making this bogus claim from the beginning, and I have debunked it several times. This is related to your erroneous claim that N-wave patterns were "scattered throughout" the tape, and that the BBN scientists dismissed the 4-second pattern merely because it was too short, when in fact it failed three of the five screening tests.
Please explain how "sampling bias" would explain the fact that N-wave and muzzle-blast patterns, plus muzzle-blast echoes, occur, in the correct order and interval, in dictabelt impulse patterns, and that they occur during the correct timespan as established by five separate time indicators on the tape.
We're talking about incredibly tiny timing windows and intervals, and yet they occur in the correct order and in the correct interval--and at the correct timespan on the tape. The patterns are never once out of order. The N-wave always comes before the muzzle blast, just as it should, and it always comes at the correct interval (10-30 milliseconds ahead of the muzzle blast), and the muzzle blast is followed by its own echo, just as it should be. You must be kidding to suggest that such astonishing correlations are due to "sampling bias."
Why don't you go comb through the articles on the acoustical evidence on McAdams' propaganda website and copy and paste any parts from those articles that explain these correlations? We both know that you can't, because no such parts exist in those articles (I've read them). Or, find an explanation for these correlations in the NRC panel's report. Alas, the NRC panel never even mentioned these correlations, much less tried to explain them.
It’s not clear there shouldn’t always be distortion in any of the BBN motorcycle positions, either from the windshield or the torso on the rider.
You know this is false. They tested for and established the effect of windshield distortion. I've pointed this out to you several times now. And, as I've also pointed out to you, McClain's torso would not have intervened between the sound waves and the microphone. The waves were coming from high above him and to his right. At the very most, a very small part of the top part of his right right shoulder might have intervened, hardly enough to cause any substantial distortion.
And yet you can find no expert who endorses Dr. Thomas’s 1-in-100,000 claim Not even from his close friends.
You're lying again. And, uh, math does not care who endorses it. Math is math. Anyone who knows math well enough can check Dr. Thomas's calculations.
If Dr. Barger disagreed with Dr. Thomas about the 1 in 100,000 probability against chance, Dr. Thomas would have noted this. Why would Dr. Barger "disagree" with the 1 in 100,000 calculation unless it were wrong, which it is not?
The only possible question about the 1 in 100,000 calculation would involve the values that Dr. Thomas assigns for a few factors in the calculation, but those values are entirely reasonable, if not a bit on the overly safe side.
And, allow me to again note that Weiss and Aschkenasy noted in their report that their "5% or less" probability of chance calculation was "highly conservative" and that the actual probability of chance was "considerably less."
Speaking of Weiss and Aschkenasy, I notice that you snipped out the observations about their sonar analysis of the grassy knoll impulse pattern.
Mr. 1-in-125 is in the research community?
I guess you're the kind of person who waxes petty and juvenile when they finally catch someone in an error, even if it is a minor error (99.17% vs. 99.2%/0.83% vs. 0.8%). My 120 vs. 125 error pales in comparison to the blunders you have made. Shall I recite the long list of your egregious gaffes again?
Yes, I am in the JFK assassination research community. My research can be found referenced in many books and articles on the case. I have had a book on the case published by JFK Lancer (Compelling Evidence). Many JFK assassination websites include a link to my website, and some of them carry or provide links to a number of my articles. I have been interviewed as a guest expert on the JFK case on BBC Canada and on some local radio stations. And I have been invited to speak at JFK assassination conferences (but could not do so because of work commitments). So, yes, I am in the research community.
Plan on reading it?
Dr. Thompson informed me three weeks ago that he's going to send me a complimentary copy. I had already pre-ordered a copy on Amazon, but I will be grateful to get an autographed copy from him. So, yes, I'll be reading it.
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Oh, dear! Yes, there are 120 ways, not 125 ways, to sequence five events. So, let's see what difference this makes in the odds: 1 in 120 is 0.83% vs. 0.8% for 1 in 125, which means the probability that the locational order in the matches is *not* the result of chance is 99.17% instead of 99.20%. I'll take 99.17%. No problem.
Your error shows a basic lack of mathematical reasoning ability. It doesn’t matter if your answer is 125, 121, 119 and that you are only off by a little bit. An answer of, let’s say 60, would be better, because that might mean you miss punched a “2” as a “1” when you multiplied 5*4*3*2*1 on a calculator. But it is clear you somehow thought that 5 to the third power would give the right answer. How do I get the correct answer? Look up the formula online? Have the formula memorized? No. I figure it out anew each time I run into the problem. If I need to find “how many ways to order 7 members (drawn without replacement) five years from now, I will figure out the formula anew, on my own. This keeps one in good practice. Relying on memory hinders one from becoming good at math.
Why does this all matter? Because it shows lack of basic mathematical ability which makes you a particularly unsuitable member of the “research community” to be the primary advocate of the Dr. Thomas 1-in-100,000 probability argument at this forum. Particularly since you can’t name any experts who publicly support this claim. The best you can do is name an expert in the field, Dr. Barger, who, while he too does not publicly support this claim, is a good friend of Dr. Thomas. And has proof read Dr. Thomas’s article, which does not tell us if he agrees with this claim or not. So, you cannot find support for this claim by Dr. Thomas and clearly you don’t have anything near the ability to evaluate it yourself. And Dr. Thomas’s claim is unbelievable. Dr. Barger, Dr Weiss do not know how to do this calculation and come within 3 orders of magnitude of the correct answer, but the insect expert Dr. Thomas does?
So, how do you explain the locational order in the matches, since the odds that such matches could be mere coincidence are 120 to 1 against?
LOL! What utter hogwash. What "sampling bias"? There was no "sampling bias." The BBN scientists examined every peak and line of every second of the dictabelt tape. You've been making this bogus claim from the beginning, and I have debunked it several times. This is related to your erroneous claim that N-wave patterns were "scattered throughout" the tape, and that the BBN scientists dismissed the 4-second pattern merely because it was too short, when in fact it failed three of the five screening tests.
Please explain how "sampling bias" would explain the fact that N-wave and muzzle-blast patterns, plus muzzle-blast echoes, occur, in the correct order and interval, in dictabelt impulse patterns, and that they occur during the correct timespan as established by five separate time indicators on the tape.
First, N-waves can be formed by lots of things, like a human voice. Take a look at a waveform caused by a voice and you will see N-waves. No acoustic expert, not Dr. Barger, not Dr. Weiss, ever claimed N-waves can only be formed by gunfire. Their claims were instead based on the similarity of a waveform with test shots recorded in 1978. The only problem is, that in most cases, the same 1963 waveform that resembled a shot from the TSBD also resembled a shot from the Grassy Knoll. That is a big problem which you seem oblivious to.
What sort of “sampling bias” to I propose. After “finding” the second shot, along a wide stretch of road, from microphone 2 ( 6 ) through 3 ( 5 ), they picked 2 ( 6 ), since it had the strongest correlation. Using it they could estimate where the first shot was, just using the Warren Report’s 11 mph estimate. It would only take one person on the BBN team to be aware of this fact to make use of it. So:
• They searched for the first shot, 137.70, around 2 ( 4 ) through 2 ( 6 ), and found a random correlation at 2 ( 5 ).
• They searched for the third shot, 139.27, around 2 ( 10 ) through 2 ( 12 ), and found a random correlation at 2 ( 11 ).
• They searched for the fourth shot, 145.15, around 3 ( 4 ) through 3 ( 8 ), and found a random correlation at 3 ( 4 ).
• They searched for the fifth shot, 145.61, around 3 ( 4 ) through 3 ( 8 ), and found a random correlation at 3 ( 5 ).
With a limited search like that, any correlation they do find will match their expectation formed after “finding” the second shot. It wouldn’t require a 1-120 chance at all.
So, once again, I have explained it to you. My theory may be true or false. But I am sure you will again ask me to explain how the correlation between time and the microphone locations could possibly occur, as if I haven’t done so already.
You could point out that I am speculating? Which I am. But if you propose they somehow completed in 10 days a compare/calculate process for all 3,024 combinations of the 7 1963 impulses with the 432 1978 impulses, you would be speculating as well. We are forced to speculate, because Dr. Barger never stated how through a search, they were able to complete in the 10 days. Did they search for the last impulse along microphones 1 ( 1 ) through 1 ( 12 )? We don’t know. But I am pretty sure they didn’t because they should have found “false alarms”, false positives, as they did from 2 ( 5 ) through 3 ( 8 ).
Why do I feel my “speculation” is superior to your speculation? Because mine explains why they had terrible correlations for the location of the shooter (finding correlations for both the TSBD and the KNOLL on the same impulse), terrible correlations for the location of the target (which generally did not match up with the location of the limousine) but good correlation for a plausible location for the motorcycle over time. Your speculation does not explain this at all.
You're lying again. And, uh, math does not care who endorses it. Math is math. Anyone who knows math well enough can check Dr. Thomas's calculations.
The key is not making the calculation. They key is knowing what values to substitute into the equation. And Dr. Barger and De. Weiss would have a better idea of this than the insect expert Dr. Thomas.
If Dr. Barger disagreed with Dr. Thomas about the 1 in 100,000 probability against chance, Dr. Thomas would have noted this. Why would Dr. Barger "disagree" with the 1 in 100,000 calculation unless it were wrong, which it is not?
No. It is far more plausible that Dr. Barger would remain silent if it disagreed with Dr. Thomas, then for him to remain silent if he agreed.
This “discovery”, would vindicate his work form 1979. It would remove a cloud that has been hanging over his head since 1982. He would try to make as many people aware of this “discovery” as possible.
On the other hand, if he disagreed, he might remain silent so as to not embarrass his friend. Besides, Dr. Barger needs all the support he can get.
Yes, I am in the JFK assassination research community. My research can be found referenced in many books and articles on the case. I have had a book on the case published by JFK Lancer (Compelling Evidence). Many JFK assassination websites include a link to my website, and some of them carry or provide links to a number of my articles. I have been interviewed as a guest expert on the JFK case on BBC Canada and on some local radio stations. And I have been invited to speak at JFK assassination conferences (but could not do so because of work commitments). So, yes, I am in the research community.
Wow. You are in real impressive company. :D
To be worthy of being a member of such a prestigious group you should brush up on your basic math skills, which are based on reasoning skills.
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Your error shows a basic lack of mathematical reasoning ability. It doesn’t matter if your answer is 125, 121, 119 and that you are only off by a little bit. An answer of, let’s say 60, would be better, because that might mean you miss punched a “2” as a “1” when you multiplied 5*4*3*2*1 on a calculator. But it is clear you somehow thought that 5 to the third power would give the right answer. How do I get the correct answer? Look up the formula online? Have the formula memorized? No. I figure it out anew each time I run into the problem. If I need to find “how many ways to order 7 members (drawn without replacement) five years from now, I will figure out the formula anew, on my own. This keeps one in good practice. Relying on memory hinders one from becoming good at math.
I hope someone is paying you to spend so much time posting such dishonest drivel. Dr. Barger himself noted that there was a 95% probability that the locational matches were not the result of chance (he was assuming only four gunshot patterns). The HSCA report also noted this. I've quoted their statements on this fact.
Plus, you can go to any math site that enables you to calculate permutations and confirm that there are 120 permutations of five objects and thus 120 ways to draw a given set of five numbers, such as the onlinestatbook.com:
http://onlinestatbook.com/2/probability/permutations.html
If the dictabelt impulse patterns are not Dealey Plaza echo patterns, then the five locational matches are purely by chance and have nothing to do with the geometry of Dealey Plaza. If so, any spurious match would be as likely to occur at any one microphone as at any other. If the five matches were merely all coincidences, then the sequence of matches in relation to the test microphone locations would have nothing to do with the location of the motorcycle--therefore, they would be in random order. But the matches are not in a random order: they are ordered 1-2-3-4-5, just as they should be if their impulse patterns were recorded by a motorcycle traveling with the motorcade.
Why does this all matter? Because it shows lack of basic mathematical ability which makes you a particularly unsuitable member of the “research community” to be the primary advocate of the Dr. Thomas 1-in-100,000 probability argument at this forum. Particularly since you can’t name any experts who publicly support this claim. The best you can do is name an expert in the field, Dr. Barger, who, while he too does not publicly support this claim, is a good friend of Dr. Thomas. And has proof read Dr. Thomas’s article, which does not tell us if he agrees with this claim or not. So, you cannot find support for this claim by Dr. Thomas and clearly you don’t have anything near the ability to evaluate it yourself. And Dr. Thomas’s claim is unbelievable. Dr. Barger, Dr Weiss do not know how to do this calculation and come within 3 orders of magnitude of the correct answer, but the insect expert Dr. Thomas does?
More of your dishonest, diversionary drivel. The reason for the overestimation has been explained to you twice now, but you just keep ignoring it and posting dishonest doubletalk.
There is no dispute that WA overestimated the probability that chance caused the correlations produced by the sonar analysis of the grassy knoll shot. The NRC panel realized this error was caused by assigning errant numbers for some of the values used in the calculation. Dr. Thomas has documented this fact in several writings, including his book, and I quoted a segment on this issue from his book a few replies ago.
And Dr. Thomas has explained in great detail why the actual odds against the chance explanation are 100,000 to 1. You have not said one word that directly deals with Dr. Thomas's detailed explanation, which includes all the math that produce those odds. As usual, you have done nothing but snipe at the point with dishonest evasions. Perhaps it is time to ask you to put up or shut up. If you have any evidence that Dr. Thomas's calculation is wrong, let's see it. Your failure to do so will be a clear admission that you can't refute it.
And I will again note that you keep ignoring the fact that WA themselves noted that their probability of chance calculation was "highly conservative" and that the actual probability was "considerably less."
First, N-waves can be formed by lots of things, like a human voice.
HUH??? This silly lie again? I've already debunked this nonsense. As I have documented for you, the BBN scientists screened all of the impulse patterns on the tape for N-wave-like characteristics. They did not have the test-firing data yet, but, being acoustical scientists who had dealt with gunfire cases before, they understood the general characteristics of N-waves and how they would appear on a oscillogram/spectrogram. This was one of the five screening tests, and only the six impulse patterns between 136.20 and 146.30 passed this test.
Sheesh, why am I having to explain this to you again? Because you won't deal honestly with the evidence.
Take a look at a waveform caused by a voice and you will see N-waves. No acoustic expert, not Dr. Barger, not Dr. Weiss, ever claimed N-waves can only be formed by gunfire. Their claims were instead based on the similarity of a waveform with test shots recorded in 1978. The only problem is, that in most cases, the same 1963 waveform that resembled a shot from the TSBD also resembled a shot from the Grassy Knoll. That is a big problem which you seem oblivious to.
You're lying again, or else you're proving that you just don't understand the evidence that I have presented to you. I also address this issue in my article, but you have said nothing about the evidence I present therein on this subject.
Let's just say this: I invite you to cite a single source on acoustics that says that actual N-waves--not sound waves that bear a general resemblance to N-waves, but waves that really are N-waves--can be formed by human speech. For a sound wave to be an N-wave, it must come before the muzzle blast, and it must do so in the very small and specific timeframe of 10-30 milliseconds, and then the muzzle blast will come after the N-wave, and then the muzzle blast will be followed by its own echo. The WA report explains how these groups of impulses appear in the graphical representation of one of the test-firing shots:
The first waveform appearing in the graph, the large peak at the left-hand side, corresponds to the supersonic shockwave [N-wave] of the rifle bullet. The second large peak is the waveform of the muzzle blast. Following it, with generally diminishing heights, are the waveforms of the echoes of the muzzle blast. The delay time of each echo was determined by direct measurement of the distance from the leading edge of the muzzle blast waveform to that of the echo. (8 HSCA 24)
And, as I've already documented several times, the grassy knoll impulse pattern contains impulses that match the abovementioned characteristics. But you just keep ignoring this fact.
A loud human yell or a burst of static can cause an impulse pattern that will generally resemble the graphical representation of an N-wave on a spectrogram or oscillogram. However, that yell or static is not going to show the N-wave coming ahead of the muzzle blast and doing so at the correct interval, and it is not going to show the muzzle-blast echo coming after the muzzle blast. Professor Aschkenasy discussed this matter in his HSCA testimony. WA were displaying an oscillogram, and Congressman Edgar thought a certain set of "squiggly lines" were caused by supersonic gunfire. Professor Aschkenasy explained the congressman's misunderstanding and explained that identifying an N-wave required a more detailed analysis:
Mr. EDGAR. How do you know that the squiggly lines you are looking at are really supersonic?
Mr. ASCHKENASY. They are not supersonic. Those are sound waves. Those are presentations of sound waves. The question, what you might want to ask, is about whether we can tell a bullet was there, namely, was it creating a supersonic shock wave? That is what you are questioning. And those are not supersonic sound waves. Those are sound waves as recorded by a microphone, and put into electrical form by the equipment that was used to transmit it and record it, and there is nothing supersonic in those squiggles that we have up there on that board.
Mr. EDGAR. Would you answer the question I wanted to ask?
Mr. ASCHKENASY. Well, because you have a bullet that travels faster than sound, it will get to someplace faster than the sound reaching that same point. We are talking about two components, the bullet and the muzzle blast.
The bullet flies, let's just pick a number, at 2,220 feet per second, so that it travels at twice the speed of sound for this particular example, when you fire the gun. And it flies, let's say for 200 feet. It will get at the target 200 feet away in a certain period of time. Just like a boat pushes the water ahead of it creating the V-shape wake behind the boat, that is similar to what you see in a shock wave from a bullet. And that shock wave is what is recorded by the microphone that is right next to the target.
Sometime later, finally the sound catches up to it and gets to the target, and the muzzle blast is recorded. That interval of time is fixed, by the fact that you have a certain muzzle velocity and you have a certain distance, they occur in a fixed time relationship.
We have also the first, it's covered by the photograph--could somebody remove that photograph, please. If I may point something out there.
Mr. EDGAR. Yes.
Mr. ASCHKENASY. I can point out here also these first impulses before the muzzle blast, those are the shock waves, and if you look carefully--I am sure you cannot look that carefully at that distance--but if you look at these graphs, because these microphones are located at different positions on the street, the relationship between the shock wave and the muzzle blast changes, and it changes in a predictable manner because the manner in which you expect them to change is related to where the observer, or the microphone is picking up both the shock waves and the muzzle blast.
Now, you measure here about on the average of about 14 milliseconds, 14 thousandths of a second delay between the shock wave and the muzzle blast. We go now here to the police tape and the measurement that we found was around 24 milliseconds here. It is now reasonable to assume because of the measured time interval that the impulse may have attributes of a shock wave.
If you expand the experiment tape and take an even better look at it, you find there is a little shock wave echo right in between the shock wave and the muzzle blast, and if you expand the police tape properly, you find similar patterns, implying to us that this impulse has the qualities, attributes of a shock wave. (5 HSCA 609-610)
You might ask yourself this question: Why do you suppose the NRC panel declined to offer any explanation for the N-waves on the dictabelt recording? Hey? Why do you suppose that was? Why do you suppose they never made your ludicrous claim that N-waves are "scattered throughout" the dictabelt recording? Hey? Why? Why do you suppose they opted not to further embarrass themselves by claiming that the N-waves were just loud human speech or bursts of static? Hey? Why?
What sort of “sampling bias” to I propose. After “finding” the second shot, along a wide stretch of road, from microphone 2 ( 6 ) through 3 ( 5 ), they picked 2 ( 6 ), since it had the strongest correlation. Using it they could estimate where the first shot was, just using the Warren Report’s 11 mph estimate. It would only take one person on the BBN team to be aware of this fact to make use of it. . . .[SNIP]
With a limited search like that, any correlation they do find will match their expectation formed after “finding” the second shot. It wouldn’t require a 1-120 chance at all.
So, once again, I have explained it to you. My theory may be true or false. But I am sure you will again ask me to explain how the correlation between time and the microphone locations could possibly occur, as if I haven’t done so already.
You could point out that I am speculating? Which I am. But if you propose they somehow completed in 10 days a compare/calculate process for all 3,024 combinations of the 7 1963 impulses with the 432 1978 impulses, you would be speculating as well. We are forced to speculate, because Dr. Barger never stated how through a search, they were able to complete in the 10 days. Did they search for the last impulse along microphones 1 ( 1 ) through 1 ( 12 )? We don’t know. But I am pretty sure they didn’t because they should have found “false alarms”, false positives, as they did from 2 ( 5 ) through 3 ( 8 ).
Why do I feel my “speculation” is superior to your speculation? Because mine explains why they had terrible correlations for the location of the shooter (finding correlations for both the TSBD and the KNOLL on the same impulse), terrible correlations for the location of the target (which generally did not match up with the location of the limousine) but good correlation for a plausible location for the motorcycle over time. Your speculation does not explain this at all.
This is just so bogus. Oh my goodness. I hate to sound like a broken record, but you leave me no choice: This is just unbelievably erroneous and misleading. You are either totally confused or you are being very disingenuous. You seem to be hoping that if you type enough words and cite enough numbers, no matter how silly or idiotic they are, that some people will think you know what you're talking about. But in fact you have, once again, totally mangled what the BBN and WA scientists did regarding false matches/false alarms and how they weighted the matches. You have also simply ignored the WA sonar analysis, which destroyed the false-match argument by reducing the microphone spacing from 18 feet to 1 foot and by reducing the acceptance window from 6 milliseconds to 1 millisecond.
The key is not making the calculation. They key is knowing what values to substitute into the equation. And Dr. Barger and De. Weiss would have a better idea of this than the insect expert Dr. Thomas.
No. It is far more plausible that Dr. Barger would remain silent if it disagreed with Dr. Thomas, then for him to remain silent if he agreed.
This “discovery”, would vindicate his work form 1979. It would remove a cloud that has been hanging over his head since 1982. He would try to make as many people aware of this “discovery” as possible.
On the other hand, if he disagreed, he might remain silent so as to not embarrass his friend. Besides, Dr. Barger needs all the support he can get.
More of your dishonest drivel. You are quite the piece of work. Again, the reason for the errantly assigned values in the WA calculation has been explained. No one disputes this. I quoted Dr. Thomas's explanation, and you did not touch a single part of it. When you replace the errant values with the correct values and redo the calculation, the odds that chance caused the grassy knoll shot come out to 1 in 100,000. Since you deny this, show us where Dr. Thomas's calculation is wrong.
And, yes, I am certain that Dr. Barger was pleased to find out that the WA probability of chance for the grassy knoll shot was actually even far lower than WA said it was. Again, why would Dr. Barger not agree with Dr. Thomas's calculation when that calculation can be verified by anyone with sufficient math skills to do so? You have ducked this question twice now? And, again, when you are going to explain why Dr. Thomas's calculation is wrong?
When Dr. Thompson's book Last Second in Dallas is released on December 3, just remember that Dr. Thompson has been consulting with Dr. Barger on the acoustical evidence for the last several years.
Wow. You are in real impressive company. To be worthy of being a member of such a prestigious group you should brush up on your basic math skills, which are based on reasoning skills.
Wow. Really? Uh-huh. Given the horrendous blunders you have committed in your amateurish attacks on the acoustical evidence, you are in no position to be telling anyone else about their mistakes. My math error was miniscule and produced a tiny difference of 0.83% vs. 0.8% and 99.17% vs. 99.2%. That error pales in comparison to your numerous embarrassing gaffes.
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I hope someone is paying you to spend so much time posting such dishonest drivel. Dr. Barger himself noted that there was a 99% probability that the locational matches were not the result of chance. The HSCA report also noted this. I've quoted their statements on this fact.
What Dr. Barger has failed to do is to state:
• Unequivocally state that all combinations of the seven-1963 impulses were compared with the 432-1978 impulses.
We need this statement, at a minimum to conclude that there was an amazing, 1-in-120, correlation between the entire data set and the position of the motorcycle, appearing to make its way up Houston and Elm in a consistent manner.
Question 1:
After 40 years, has Dr. Barger ever made such a clear statement?
Yes, we know there is good correlation with the consistent progress of the motorcycle hypothesis with the data the BBN did check in 1978. But this is meaningless unless we know that all possible correlations were checked.
If BBN only checked for correlations:
For the first shot, between microphones 2 ( 5 ) and 2 ( 6 ),
for the second shot, between microphones 2 ( 6 ) and 3 ( 5 ),
for the third shot, between microphones 2 ( 11 ) and 2 ( 11 ),
for the fourth shot, between microphones 3 ( 4 ) and 3 ( 8 ),
for the fifth shot, between microphones 3 ( 5 ) and 3 ( 8 ),
then there is no amazing 1-in-120 coincidence. The correlations they do find would naturally match the scenario of a motorcycle moving forward.
For all we know, if a complete search was done, we might find:
• correlations for the first, second and third shots in the range of microphones 3 ( 9 ) through 3 ( 12 ),
• correlations for the fourth and fifth shots in the range of microphones 1 ( 1 ) through 2 ( 4 )
and we would find what we found with the “location of the shooter” and the “location of the target” correlations, random correlations for the “location of the motorcycle”.
So, again, ideally, I would like from Dr. Barger:
• Unequivocally state that all combinations of the seven-1963 impulses were compared with the 432-1978 impulses.
• State the time needed to check and calculate one combination of 1963 impulse with a 1978 impulse.
• The number of men assigned to this task.
• The number of man hours that were used in this task alone.
• A statement that these were “blind” comparisons. That the checker did not know which of the seven impulses he was checking nor which microphone he was checking for. This would eliminate the expectations of a checker failing to find a correlation for the fourth shot at microphone 1 ( 7 ) because he thought any such correlation would be impossible.
But after 40 years, we have had no such statement from Dr. Barger.
One last time, regarding the match between the data being consistent with a motorcycle making progress down Houston and Elm:
• if a complete, thorough, unbiased, comparison of all seven-1963 impulses were each compared to all 432-1978 impulses, then can we conclude that the odds were 1-in-120. Well, actually somewhat less than that because some of the found correlations were out of order.
• But if this was not done than the true odds may be more like 1-in-1, depending on how incomplete the search was.
There is no dispute that WA overestimated the probability that chance caused the correlations produced by the sonar analysis of the grassy knoll shot. The NRC panel realized this error was caused by assigning errant numbers for some of the values used in the calculation. Dr. Thomas has documented this fact in several writings, including his book, and I quoted a segment on this issue from his book a few replies ago.
And Dr. Thomas has explained in great detail why the actual odds against the chance explanation are 100,000 to 1. You have not said one word that directly deals with Dr. Thomas's detailed explanation, which includes all the math that produce those odds. As usual, you have done nothing but snipe at the point with dishonest evasions. Perhaps it is time to ask you to put up or shut up. If you have any evidence that Dr. Thomas's calculation is wrong, let's see it. Your failure to do so will be a clear admission that you can't refute it.
Dr. Thomas has explained this, but you can find no expert who agrees with him. Only an expert who agreed to proof-read his work and who has become a good friend of his. But no statement from any expert who says Dr. Thomas is correct about this 1-in-100,000 estimate of the chance.
And I will again note that you keep ignoring the fact that WA themselves noted that their probability of chance calculation was "highly conservative" and that the actual probability was "considerably less."
As to be expected if they had actually made “highly optimistic” estimates due to being subconsciously influenced by “p-hacking”. Which just happened to cause them to arrive at a p-value of 95%. The ultimate goal of those under the influence of p-hacking.
HUH??? This silly lie again? I've already debunked this nonsense. As I have documented for you, the BBN scientists screened all of the impulse patterns on the tape for N-wave-like characteristics. They did not have the test-firing data yet, but, being acoustical scientists who had dealt with gunfire cases before, they understood the general characteristics of N-waves and how they would appear on a oscillogram/spectrogram. This was one of the five screening tests, and only the six impulse patterns between 136.20 and 146.30 passed this test.
You and Dr. Barger have something in common. You both fail to see that there are not six impulses but seven. They are all listed on BBN’s Exhibit F-367. I will list them again. They are:
https://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm (https://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm)
136.20
137.70
139.27
140.32
145.15
145.61
146.30
They thought all seven were possible candidates as gunshots. They did comparisons of each with some of the 432-1978 recordings. They rejected 136.20 and 146.30 as gunshots because they could not find any correlation stronger than 0.5.
Nowhere do they state, from their “N-wave” characteristics or for any other property, that they were gunshots. It was only through the similarity of 4 of the waveforms with some of the 1978 test impulses that they concluded that these 4 were gunshots.
Again, you seem to be the only one who thinks, that from the 1963 impulses alone, one can tell that they could only be formed by gunshots.
Question:
Where is the statement form the BBN that N-waves can only be formed by gunfire?
Question:
If these N-waves can only be formed by gunfire, why did they reject the impulses at 136.20 and 146.30, as shown on BBN Exhibit F-367?
From reading their statements I glean that the BBN settled on these seven impulses because:
• The number of impulses match the very upper limit to the number of shots that may have been fired.
• The seven impulses occurred over a span of 10.1 seconds, and they made it clear they were looking for a span of at least 5 seconds.
These is nothing form their statements, that from these seven impulses alone, that they could tell that these were formed by gunshots. You seem to be the only one who makes this claim.
Eventually, they only concluded that they were gunshots, because of their similarity to either a test shot from the TSBD or a test shot from the Grassy Knoll. The only problem is, and it is a whopper, is that 3 of the shots had similarities with both a test shot from the TSBD and a test shot from the Grassy knoll. Indicating that they were finding at least some false correlations, what they called “false alarms”. Which casts doubt on all their correlations. I’m not lying. This is what their own data, in BBN Exhibit F-367 shows. Dr. Barger seems to have turned a blind eye to what his own data was trying to tell him.
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Below is large segment from Dr. Donald Thomas's discussion on the WA sonar analysis in his book Hear No Evil: Politics, Science, and the Forensic Evidence in the Kennedy Assassination. In the segment below, Dr. Thomas explains every step in the WA sonar analysis and the findings that came from the analysis, the key finding being that the dictabelt tape contains the impulse pattern of a shot fired from the grassy knoll during the assassination.
Dr. Thomas is a USDA entomological research scientist and an expert in statistical analysis. His first, and ground-breaking, article on the acoustical evidence was published in the peer-reviewed criminal science journal Science & Justice. It's worth noting that Dr. James Barger, the lead BBN acoustical scientist for the HSCA, proof-read the article before it was published. Also, Dr. Thomas consulted extensively with Dr. Barger while writing the four chapters on the acoustical evidence in his book. Here is the segment from Dr. Thomas's discussion on the WA sonar analysis:
When Mark Weiss and Arnold Aschkenasy were asked by the Assassinations Committee to review and refine BBN's analysis of the Dallas Police recordings, it was specifically for the purpose of moving Barger's 50-50 estimate off the fence. BBN's analysis was adequate to meet its limited objectives, so far as they went. Barger and his team had spread a net to catch a motorcycle and they had succeeded. The order in the data meant that the sounds of the assassination gunfire were almost certainly on the police recording. But when it came to nailing down the number of shots and their origins, the conclusions were more tenuous. Call them what you will, false alarms or auto-correlations, the detection method was too porous to assure that quirks and spurious matches wouldn't leak through. The primary weakness in the analysis was in the width of the coincidence windows. The solution to the problem was to narrow those windows to a slit.
The only way to narrow the coincidence windows was to get a better fix on the motorcycle position. It was unlikely that microphone No. 4 was exactly in the same spot as the subject motorcycle, if one was there, and very likely to be off by six feet or more. One solution would be to go back to Dealey Plaza and saturate the area around microphone No. 4's position with microphones at 2-foot spacings and record more test shots. For a street 36 feet wide, and to cover nine feet in each direction, 180 microphones would be required to cover the relevant area. This procedure would narrow the coincidence windows to ±1 millisecond, but it raises other problems.
Measuring echo delay times to within an accuracy of one millisecond requires consideration of the fact that the subject microphone was in motion. During the one-third of a second that the gunshot resounds, the motorcycle would have moved several feet. Thus, in order to duplicate the conditions during the assassination, one would have to array 180 mobile microphones and have them moving in the same direction and at the same speed as the suspect motorcycle. The logistics of such an exacting experiment would be impractical. But, essentially, that is what Weiss and Aschkenasy did - but they did it analytically.
The basic principles of echo location are well known; well enough that submarines don't have windows. A submarine navigates acoustically by bouncing sounds off of its environment. The on-board computer calculates the distances and angles to surrounding objects as it moves through the water based on the echo delay time. The algorithms in the computer's sonar software adjust for the vessel's speed and compensates for the temperature of the water. Sound travels slower in polar waters than it does through the warm waters off say, the coast of Cuba. Weiss and Aschkenasy were the ones who wrote those software programs and they now applied the same principles to the patterns on the DPD recording.
If the impulses on the tape were the echoes of gunfire reflecting and refracting off of the structures in Dealey Plaza, then the first step in the solution lay in matching the echoes to those structures. Weiss and Aschkenasy obtained a surveyor's map showing the buildings, monuments, and other structures in Dealey Plaza accurate to within one foot. They placed a pin at the position where BBN had placed a shooter on the grassy knoll and a pin on the microphone position (No.4 of Array 3) on Elm Street which had recorded the test pattern which correlated to the impulse pattern on the police tape. With a string attached to both pins they proceeded to measure the precise distances along the most direct paths from the shooter position to each structure in Dealey Plaza, and from there directly to the microphone.
They included every structure that presented a significant sound reflecting surface or sound refracting comer in the northeastern quadrant of Dealey Plaza. Eventually they were able to correlate twenty-two such structures in all, accounting for 26 major echoes or re-echoes.
In spite of such perfection, the match so obtained, though impressive, was only a start. The evidence tape was dense with impulses, most of which were piston firings from the motorcycle's motor. There were so many and they were so closely spaced, at least some could be expected to align with impulses on the test pattern, and there was a mathematical probability that many could by chance.
So, for the next step in the analysis, Weiss and Aschkenasy used amplitude as the criterion to eliminate the motor noise impulses, basically the same procedure used by the BBN team, except that they had now identified a specific impulse in the evidence pattern as the putative muzzle blast.70 Including only the large amplitude impulses, those loud enough to exceed a sound threshold determined by the average background noise, a total of 13 such loud impulses on the test pattern remained and 15 such impulses on the DPD recording. When the echo delay times were compared, eleven of the impulses were coincident to within ±1
millisecond, giving a binary correlation coefficient of 0.79.71 A probability calculation of the odds of attaining this good a match from a chance assemblage of static or noise impulses was calculated to be about 5%.72 Thus, Weiss and Aschkenasy had succeeded in moving the mathematical probability for the grassy knoll gunshot from an anemic 50% to a robust 95%. (Thomas, Hear No Evil, 2010, pp. 593-595)
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Below is large segment from Dr. Donald Thomas's discussion on the WA sonar analysis in his book Hear No Evil: Politics, Science, and the Forensic Evidence in the Kennedy Assassination. In the segment below, Dr. Thomas explains every step in the WA sonar analysis and the findings that came from the analysis, the key finding being that the dictabelt tape contains the impulse pattern of a shot fired from the grassy knoll during the assassination.
Dr. Thomas is a USDA entomological research scientist and an expert in statistical analysis. His first, and ground-breaking, article on the acoustical evidence was published in the peer-reviewed criminal science journal Science & Justice. It's worth noting that Dr. James Barger, the lead BBN acoustical scientist for the HSCA, proof-read the article before it was published. Also, Dr. Thomas consulted extensively with Dr. Barger while writing the four chapters on the acoustical evidence in his book. Here is the segment from Dr. Thomas's discussion on the WA sonar analysis:
Yet not one acoustic expert has expressed any support for Dr. Thomas’s most important claim. That there is only a 1-in-100,000 chance that correlation found by Weiss and Aschkenasy correlates with the impulse at 145.15 by random chance. Not even Dr. Barger.
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Yet not one acoustic expert has expressed any support for Dr. Thomas’s most important claim. That there is only a 1-in-100,000 chance that correlation found by Weiss and Aschkenasy correlates with the impulse at 145.15 by random chance. Not even Dr. Barger.
And not one acoustical expert has disputed Dr. Thomas's calculation, even though it first appeared in his article in a peer-reviewed criminal science journal in 2001, and even though that article drew international attention. Furthermore, no critic of the acoustical evidence has yet refuted Dr. Thomas's calculation.
I have asked you several times to explain why you reject Dr. Thomas's calculation, but so far you have refused to do so.
I am also still waiting for you to explain the locational correlations between the dictabelt impulse patterns and five of the test-firing shots. If the dictabelt impulse patterns were the result of static, no one would expect them to match the five test shots in the correct locational order, given that the odds of doing so are 1 in 120.
The NRC panel was smart enough, and dishonest enough, not to try to explain this remarkable order in the data: they just ignored it.
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And not one acoustical expert has disputed Dr. Thomas's calculation, even though it first appeared in his article in a peer-reviewed criminal science journal in 2001, and even though that article drew international attention. Furthermore, no critic of the acoustical evidence has yet refuted Dr. Thomas's calculation.
I have asked you several times to explain why you reject Dr. Thomas's calculation, but so far you have refused to do so.
Many people write all sorts of stuff that I don’t read. At a minimum, Dr. Thomas must first receive some support from acoustic experts for me to look into it. It makes so sense for Dr. Barger, Dr. Weiss and Mr. Aschkenasy to remain silent on this if there was any truth to Dr. Thomas’s 1-in-100,000 odds claim.
Also, Weiss and Aschkenasy have not provided enough information for me to even begin to calculate the odds. I know they used a computer programs to calculate the expected waveform:
• From various positions within a few feet of microphone 3 ( 4 )
• From various positions of the shooter within a few feet of the 1978 Grassy Knoll position
And see which combinations of microphone positions and shooter positions matches the 1963 145.15 impulse.
But how many microphone positions did they simulate? How many shooter positions did they simulate? If they simulated 300 positions each, that gives 90,000 unique pairs of positions that the computer could try to match up. It seems like one should find some pretty good correlations from sheer chance if they checked out that many permutations. But Weiss and Aschkenasy never provided us with this basic information. So, without it, I don’t see how anyone can come up with a good probability calculation.
Question 1:
How many permutations of hypothetical shooter and motorcycle positions did Weiss and Aschkenasy simulate when they ran their computer program, to generate waveforms to compare with impulse 145.15?
Question 2:
How does one calculate the odds of Weiss and Aschkenasy coming up with such a good correlation, without knowing the number of permutations of hypothetical shooter and motorcycle positions they simulated on the computer ?
I am also still waiting for you to explain the locational correlations between the dictabelt impulse patterns and five of the test-firing shots. If the dictabelt impulse patterns were the result of static, no one would expect them to match the five test shots in the correct locational order, given that the odds of doing so are 1 in 120.
The NRC panel was smart enough, and dishonest enough, not to try to explain this remarkable order in the data: they just ignored it.
Ridiculous. I have explained out this order can come about many times without involving any kind of coincidence. You think others won’t notice this?
Question 3:
If BBN only checked:
between microphones 2 ( 4 ) and 2 ( 6 ) for the first shot,
between microphones 2 ( 6 ) and 3 ( 5 ) for the first shot,
between microphones 2 ( 10 ) and 2 ( 12 ) for the first shot,
between microphones 3 ( 4 ) and 3 ( 8 ) for the first shot,
between microphones 3 ( 5 ) and 3 ( 8 ) for the first shot,
won’t there be a much better chance than 1-in-120 for the “motorcycle position” for the correlations they do find to come up in the proper order?
Are you going to continue to ignore 3 simple questions and hope the other readers won’t notice?
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I have mentioned the often-overlooked fact that the NRC panel concluded that there was only a 22% probability that chance caused the correlations between the dictabelt grassy knoll shot (the 145.15 impulse pattern) and the test-firing grassy knoll shot. Yes, a 22% probability of chance is higher than a “5% or less” probability of chance, but it is still not a very good chance.
If someone offered you an investment that had only a 22% chance of earning a profit, you would decline it. If a candidate received only 22% of the vote in an election, he would be judged to have lost in an enormous landslide. If a mechanic gave you an estimate of $4,000 for a car repair and added that there was only a 22% chance the repair would actually fix the problem, you would say “no thanks” (unless you were very rich). If you discovered that you had cancer and that you had only a 22% chance of beating it, you would start getting your affairs in order in anticipation of your probable death. Any way you slice it, a 22% chance is not a good bet.
Of course, a 22% probability that chance (random noise) caused the correlations equals a 78% probability that gunfire caused the correlations. The fact that the NRC panel, even after making several dubious assumptions in their calculations, said there was a 78% chance that the 145.15 impulse pattern was caused by gunfire gives us some idea of just how strong and solid the WA sonar analysis was.
I quote from the NRC panel’s report (keep in mind that “P” here equals the probability of chance, and that P=0.223 means a probability of chance of 22%):
Thus 10 coincidences among 12 predicted echoes and 14 impulses out of 45 windows should be adjusted to 8 coincidences among 11 predicted echoes and 12 impulses out of 90 windows. If we now reduce the number of coincidences by 7 to make a conservative adjustment for the “free” parameters, we would have 1 coincidence among 4 predicted echoes and 5 impulses out of 83 windows. The hypergeometric probability calculation would then yield a significance level of P=0.223, which is not at all impressive in contrast to the claim that P=0.053. However, this adjustment may be unduly conservative. (NRC panel report, p. 40)
Did you catch the last sentence: the NRC panel’s “adjustment” may have been “unduly conservative”? This is an understatement. Dr. Thomas explains just how badly and errantly the NRC panel played with the numbers in order to get the probability of chance up to 22%:
But, because of using the incorrect values for M and i, BBN had grossly overestimated the probability that a random burst of noise could have matched the test pattern. This was obviously an honest mistake because the error worked against their own conclusion by increasing the probability of coincidence by chance. It is interesting that the NRC panel caught this error and knew that the correct number of time slots was 90 and not 45. It proves that they did understand that the 190 millisecond gap between the two 90 millisecond bursts occurred in the middle of the impulse pattern and were not two completely separate patterns as they had asserted in their critique of the HSCA analysis. . . .
Aware of the error made by BBN in assigning the value of M, the NRC panel looked for errors in the values of N, n and i. In scrutinizing the echo path data they noticed a discrepancy in the echo matching procedure. Among the 12 pertinent echoes in the Dealey Plaza test shot there were some that arrive at the microphone quite close together. One pair of echoes, designated 19 and 20, were separated by only 3 milliseconds on the test pattern. Applying the sonar model to the echo delay times predicted that these two echoes would have arrived precisely coincident with one another when the microphone was moved analytically to the predicted motorcycle position. In fact, there is only one spike in the evidence pattern at the corresponding echo delay location. Weiss and Aschkenasy scored the two echoes as separate coincidences giving a contribution of 2, 2, and 2 to the values of N, n and I respectively.
The NRC panel took the position that because there really is only spike in the evidence pattern in this position, and one in the predicted pattern, the contribution to N, n and i should have been 1, 1, and 1 respectively. Because there really are two echoes involved, the assigned values were not really an error on the part of Weiss and Aschkenasy. Rather, of the two reasonable alternative scoring procedures the NRC procedure was simply the more conservative. Adopting the conservative approach gives a number set of {90, 13, 11, 9}.
A similar problem involved echo numbers 23 and 24. On the test tape the impulses are separated by only 5 milliseconds. The sonar model predicts their arrival will be much closer, though not exactly coincident, approximately 1 millisecond apart, when the microphone is moved to the predicted motorcycle position. Likewise, the two echoes on the evidence tape at this echo delay location are about 1 millisecond apart. Again, Weiss and Aschkenasy scored the two echoes as contributing values of 2, 2, and 2 to the parameters N, n and i, respectively.
But the NRC panel argued that the coincident windows should be non-overlapping, and because the windows are 2 milliseconds wide the scoring should count only one coincidence not two. Inasmuch as there really are two echoes on the test tape, two separate spikes on the evidence tape, and two predicted echoes on the sonar model, the reduction from two to one coincidence in this case seems overly conservative.
In fact, the NRC panel scored the contributions to the parameters N, n and i as I, 2 and I, respectively, in effect, insisting on counting an echo for which they would not allow a match. Even accepting the overly conservative approach to scoring which insisted on nonoverlapping windows, their assigned score was clearly inappropriate. By the NRC scoring the number set was now {90, 12, II, 8}.
In this manner the NRC panel whittled away at the data set. Most of this whittling was accomplished by further reducing the number of allowed coincident impulses.
The NRC panel identified seven assumptions made by Weiss and Aschkenasy in constructing their sonar model. These were: that the time of the muzzle blast was coincident with the first impulse on the evidence tape, that the air temperature was 65 degrees F, that the tape recorder speed was slow by 4.3 percent, that the location of the motorcycle when the muzzle blast arrived was 72 ft. west of the intersection, that the motorcycle was traveling at 11 mph, and that the shooter was 8 ft. west of the corner of the fence on the grassy knoll. The final calculation of the odds depends on how one chooses to account for these assumptions. Were these reasonable assumptions, or had Weiss and Aschkenasy just picked out numbers that would give the best fit?
There is a formal way to do this. When a parameter is unknown, its value is said to be a "free variable." For example, the HSCA analysts recognized that the motorcycle position was a free variable and had thus adjusted their calculation of p by multiplying by a factor of 180 for the 180 possible positions around microphone 4(3). Alternatively, one can adjust for free variables by deducting directly from the values of the parameters in the formula. In statistical analysis these corrections of a parametric value are called "degrees of freedom."
The NRC panel decided that the assumptions in the sonar model involved 7 degrees of freedom and therefore deducted 7 coincident pairs from the data set. The number set which the NRC panel wound up with by deducting 7 for each parameter, beginning with their "corrected" number set of {90, 12, 11, 8} was {83, 5, 4, 1}. One assumes that they left the lone coincident because if they had whittled away at the data any further they would have left themselves without any data to argue from. The probability given by this number set calculates out to 20.7 percent (the NRC reported 22 percent). The estimate of 22 percent was much less impressive than the industry standard of 5 percent. The panel had attained its goal - final score: NRC 22, HSCA 5.
But, again, the validity of each of the assumptions, and the manner in which the adjustments were applied to the number set, is questionable. Certainly, the motorcycle position was a free variable. Weiss and Aschkenasy had, in essence, "selected" the position which gave the best match between the test and evidence patterns. Because the motorcycle position was free to vary in two dimensions, the NRC panel rightly deducted two degrees of freedom.
The shooter position was also an uncertain parameter and therefore a free variable. The NRC panel also figured this assumption was worth two degrees of freedom. But, in reality, the shooter's position on the grassy knoll was not free to move in two dimensions, but only one. The shooter could not have been any distance away from the fence, and thus, was only free to move in one dimension, i.e., along the fence.
But the other parameters cited by the NRC were not free variables at all. In fact, had these factors not been included, the analysis could be fairly criticized. The velocity of the motorcycle, the air temperature, and the tape recorder speed, all factors in the sonar model, were actual measurements, not unknowns.
Weiss and Aschkenasy had used values for these parameters such as the air temperature and motorcade speed, provided by BBN and the HSCA staff, all of which were derived from evidence independent of the acoustical analysis. They did find that a small adjustment of tape speed of 4.3 percent, rather than BBN's measurement of 5%, gave the best fit. Nevertheless, it seems unduly conservative to insist that these adjustments be treated as free variables as if they were numbers plucked out of the air to obtain a fit, rather than measured parameters. Even allowing for the validity of all of the NRC panel's adjustments, one was duplicated.
The NRC panel eliminated the erroneous adjustment for the M value by BBN, but failed to recognize that Weiss & Aschkenasy had already made the adjustment for the alignment of the muzzle blast with the first impulse. Just putting back one for the overt error in the deduction for this alignment gives a data set of {84, 6, 5, 2}. The probability of this coincidence set is 3.7 x 10-2 or, about 3.7 percent. Even better than Weiss and Aschkenasy's original five percent!
The most appropriate estimate of the true probability would assign two degrees of freedom for the motorcycle location, one for shooter location, one for the alignment of the muzzle blast, and eliminate one pair of echoes and their coincidence (from pairs 19 and 20), giving a final number set of {86, 10, 8, 6} which calculates to 1.12 x 10-5, or, 100,000 to 1, against. (Hear No Evil, pp. 629-632)
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I have mentioned the often-overlooked fact that the NRC panel concluded that there was only a 22% probability that chance caused the correlations between the dictabelt grassy knoll shot (the 145.15 impulse pattern) and the test-firing grassy knoll shot. Yes, a 22% probability of chance is higher than a “5% or less” probability of chance, but it is still not a very good chance.
If someone offered you an investment that had only a 22% chance of earning a profit, you would decline it. If a candidate received only 22% of the vote in an election, he would be judged to have lost in an enormous landslide. If a mechanic gave you an estimate of $4,000 for a car repair and added that there was only a 22% chance the repair would actually fix the problem, you would say “no thanks” (unless you were very rich). If you discovered that you had cancer and that you had only a 22% chance of beating it, you would start getting your affairs in order in anticipation of your probable death. Any way you slice it, a 22% chance is not a good bet.
Of course, a 22% probability that chance (random noise) caused the correlations equals a 78% probability that gunfire caused the correlations. The fact that the NRC panel, even after making several dubious assumptions in their calculations, said there was a 78% chance that the 145.15 impulse pattern was caused by gunfire gives us some idea of just how strong and solid the WA sonar analysis was.
I quote from the NRC panel’s report (keep in mind that “P” here equals the probability of chance, and that P=0.223 means a probability of chance of 22%):
Did you catch the last sentence: the NRC panel’s “adjustment” may have been “unduly conservative”? This is an understatement. Dr. Thomas explains just how badly and errantly the NRC panel played with the numbers in order to get the probability of chance up to 22%:
The only type of acoustic test worth evaluating is one that, at a minimum, checks the correlation of:
• every 1963 impulses, all 7 of them,
with:
• every 1978 test shot, all 12 of them,
• every 1978 microphone position, all 36 of them,
and gives a complete list of all found correlations that exceed a certain threshold.
It is difficult to calculate the probability that a found correlation is the result of chance. One expert might say it is 22%, another 5%, another 0.001%. Who do you belief?
But if strongest correlations that don’t conflict with each other and the complete list of the strongest correlations look something like:
*********** Warning, False Data just to make a point ***********
shot 1 fired from TSBD, fired at 200 feet from Houston Street, recorded at 100 feet from Houston Street,
shot 2 fired from TSBD, fired at 220 feet from Houston Street, recorded at 120 feet from Houston Street,
shot 3 fired from TSBD, fired at 240 feet from Houston Street, recorded at 140 feet from Houston Street,
shot 4 fired from knoll, fired at 300 feet from Houston Street, recorded at 200 feet from Houston Street,
shot 5 fired from TSBD, fired at 320 feet from Houston Street, recorded at 220 feet from Houston Street,
this would be consistent with the recording being made at Dealey Plaza, since:
• none of the correlations contradict one another, like finding correlations for the same shot from both the TSBD and the knoll,
• none of the correlations contradict a likely fact, like targets that do not approximately correspond to the location of the limousine,
• none of the correlations contradict a likely fact, like motorcycle locations that don’t match up with a motorcycle proceeding forward at all times
There must be reasonable correlations for all three, the locations of the rifle, the location of the target, the location of the motorcycle. Getting only two of three or one of three correct is no good.
However, if we get strong correlations that contradict each other or highly probable facts, like:
• correlation of the same 1963 impulse with both a test shot from the TSBD and the knoll,
• correlation with the target location not matching the approximate limousine location,
• correlation of the motorcycle position indicating a reversal of direction,
then we know we have found no good evidence that the recording was made at Dealey Plaza. This is certainly not the case of the BBN correlations found in August 1978 and recorded in BBN Exhibit F-367.
It doesn’t matter if some expert claims the odds of getting a correlation is only 5%, or 1%, or 0.001%. We know these correlations are invalid because they contradict one another.
The Weiss and Aschkenasy study have no such problems, but it was impossible for it to have these problems. Because they didn’t run correlations of different 1963 impulses, with different 1978 test shots, recorded at different positions. They only compared one 1963 impulse with one 1978 test shot recorded from one 1978 microphone position. Guarantying no correlation contradictions would be found, regardless of whether the recording was made at Dealey Plaza, or the Trade Mart Center, or anywhere else. Making the Weiss and Aschkenasy tests a waste of time.
One final point, I like the BBN study a lot better than the Weiss and Aschkenasy study. If someone makes the claim that “The odds of any of the BBN correlations being a result of random chance are 1-in-100,000”, it is easy for me to refute this. Because many of the correlations they found contradict each other. Of course, if amazingly enough, none of the correlations contradicted each other, this claim would have to be taken seriously as at least being possibly true.
But if one claims “The odds of the Weiss and Aschkenasy correlation being a result of random change are 1-in-100,000”, it is not easy to automatically refute this. Because the Weiss and Aschkenasy made such limited comparisons that it was impossible for any contradiction to be found, since they were only comparing one 1963 impulse, with one 1978 firing test, fired from one position, fired at one target. Instead, I have to use other means of discounting this claim. Like pointing out that no acoustic expert has expressed any support for this claim. True, no acoustic expert has expressed any opposition to this claim either. But scientists don’t usually comment on the claims of cranks talking outside their own field of expertise.
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Lately I have been re-reading the NRC panel’s report. I began to do so mainly to double-check the exact wording they used when they said there was only a 22% probability that chance (random noise) caused the correlations between the dictabelt grassy knoll shot and the test-firing grassy knoll shot.
As I documented in my previous post, the NRC panel used dubious, invalid values in order to calculate the probability of chance for the grassy knoll shot as being 22%. When I first read this way back when, I thought, “But that means you’re admitting there’s a 78% probability that the 145.15 impulse pattern was caused by gunfire from the grassy knoll!” The NRC panel could not even bring themselves to state this.
Anyway, in re-reading the NRC panel’s report, I can see why the HSCA acoustical scientists treated it so dismissively. The report does not even mention, much less try to explain, the locational order in the matches between the dictabelt gunshots and the test-firing gunshots. The report does not even mention the fact that the dictabelt gunshot impulse patterns indicate the microphone was moving at the same average speed as the motorcade. The report does not even mention, much less explain, the fact that N-waves not only appear in the dictabelt gunshots when they should, and do not appear when they should not, but that when they appear, they do so in the correct order and interval in relation to the muzzle blast. I mean, the report literally says nothing—not one word—about any of these correlations.
What makes the report’s silence even more discrediting and damning is fact that the report indicates that the NRC panel understood that such correlations would be expected to be found in the dictabelt impulse patterns if assassination gunfire caused those patterns. For example, the NRC panel’s report admits that the Dealey Plaza test firing proved that for each shot fired in Dealey Plaza there will be “a characteristic and complex pattern of echoes”:
For each combination of shooter location and microphone location, there is a characteristic and complex pattern of echoes in the recording of the test shot. . . . (NRC panel report, p. 8 )
Yet, the panel chose to say nothing about the fact that the HSCA acoustical scientists documented that at least four of the dictabelt impulse patterns contain the “characteristic and complex pattern of echoes” of four of the Dealey Plaza test-firing shots.
Revealingly, the report shows that the NRC panel understood that the shock wave (N-wave) comes before the muzzle blast and that the muzzle blast is followed by gunfire echoes. The report mentions this fact in the same paragraph quoted above:
For each combination of shooter location and microphone location, there is a characteristic and complex pattern of echoes in the recording of the test shot, because after the first sounds travel by a direct path to the microphone (usually the bullet shock wave and the muzzle blast sound), subsequent sounds arrive (due to echoes from buildings and other large objects) with varying delays, depending on the length of the path they have taken. (NRC panel report, p. 8 )
Well, well, so the panel members did know that there is a defined order in how and when the sounds of the shock wave (N-wave), the muzzle blast, and the N-wave and muzzle-blasts echoes (“subsequent sounds”) will travel and be recorded—as long as the microphone is in position to record them, of course. The HSCA acoustical experts spent a fair amount of time talking about this fact. They explained—and one can confirm this in ballistic-acoustics literature—that the N-wave will always come before the muzzle blast and will do so in a predictable interval, that the muzzle blast will come behind the N-wave, and that N-wave and muzzle-blast echoes will come last.
Yet, the panel chose to say nothing about whether or not N-waves appear on the dictabelt recording. Thus, needless to say, the panel said nothing about the fact that N-wave impulses occur in the dictabelt gunshots when they should, and do not occur when they should not; that they occur in the correct order and interval in relation to the muzzle-blast impulses; and that echoes of them occur afterward.
Another line of evidence that the NRC panel’s report ignores is the windshield-distortion correlations. The failure to even mention, much less address, the windshield-distortion correlations is suspicious and revealing. The HSCA acoustical scientists conducted a test to determine the acoustical characteristics of windshield distortion, because they correctly suspected that such distortion would occur whenever the windshield was between the shooter and the microphone. And, lo and behold, they found that windshield distortion occurs in every dictabelt gunshot where it should and does not occur in the one dictabelt gunshot where it should not.
The NRC panel was surely aware of the windshield-distortion correlations. The HSCA acoustical experts talked about them during the hearings, and the HSCA report highlighted them:
Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone. On shot four, Weiss and Aschkenasy found no such distortion. The analysts' ability to predict the effect of the windshield on the impulses found on the dispatch tape, and having their predictions confirmed by the tape, indicated further that the microphone was mounted on a motorcycle in Dealey Plaza and that it had transmitted the sounds of the shots fired during the assassination. (HSCA report, pp. 74-75)
Perhaps the NRC panelists chose not to even mention these remarkable correlations, as well as the other correlations, because they feared that their all-or-nothing reliance on the Decker “hold everything” crosstalk would look lame by comparison. Perhaps the panelists feared that many people would logically observe, “Since you are claiming that the dictabelt gunshot impulse patterns are not gunshots and were not even recorded during the assassination, you are asking us to believe that the correlations documented by the HSCA acoustical experts are all just astounding coincidences. That seems very hard to believe.”
We can understand why the NRC panel’s report is so bad when we realize that the panel’s leading member, its driving force, was Dr. Luis Alvarez, who was an ardent Warren Commission defender and who was caught fabricating his own test data to defend the commission’s claims. When BBN acoustical scientist Dr. James Barger, one of the HSCA acoustical experts, met with the NRC panel, Alvarez told him that he was going to vote against the HSCA findings no matter what Dr. Barger said. Dr. Donald Thomas:
The NRC report is replete with false and erroneous statements. James Barger, the lead scientist with BBN, met with the panel in an effort to explain his analysis and defend his conclusions. But, according to Barger, Alvarez told him it didn't really matter what he had to say, he (Alvarez) was going to vote against the HSCA findings anyway. (Thomas, Hear No Evil, p. 619)
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Lately I have been re-reading the NRC panel’s report. I began to do so mainly to double-check the exact wording they used when they said there was only a 22% probability that chance (random noise) caused the correlations between the dictabelt grassy knoll shot and the test-firing grassy knoll shot.
As I documented in my previous post, the NRC panel used dubious, invalid values in order to calculate the probability of chance for the grassy knoll shot as being 22%. When I first read this way back when, I thought, “But that means you’re admitting there’s a 78% probability that the 145.15 impulse pattern was caused by gunfire from the grassy knoll!” The NRC panel could not even bring themselves to state this.
This 78% probability is true. If we cherry pick what facts to consider. But when we consider all factors, the probability drops:
• Several people are within 50 feet of the fairly exposed grassy knoll sniper position, Mr. Zapruder, Ms. Sitzman, the young black couple who dropped a coke bottle, others on the steps below them. A strange shooting position where one would think a shooter wouldn’t want to be on ground where anyone could walk up to them.
• The Grassy Knoll was filmed during the shooting but no clear image of a life size human who is a possible shooter is seen.
• The difficulty a shooter would be giving themselves by choosing a position where they would have to fire a shot at a moving target that is moving at almost at a right angle relative to them, giving the target a near maximum angular velocity.
• No shells recovered from the grassy knoll.
Anyway, in re-reading the NRC panel’s report, I can see why the HSCA acoustical scientists treated it so dismissively. The report does not even mention, much less try to explain, the locational order in the matches between the dictabelt gunshots and the test-firing gunshots. The report does not even mention the fact that the dictabelt gunshot impulse patterns indicate the microphone was moving at the same average speed as the motorcade. The report does not even mention, much less explain, the fact that N-waves not only appear in the dictabelt gunshots when they should, and do not appear when they should not, but that when they appear, they do so in the correct order and interval in relation to the muzzle blast. I mean, the report literally says nothing—not one word—about any of these correlations.
Yes, but I have provided an explanation for this many times, which you ignore. If they checked the eastern microphones for the early shots, the western microphones locations for the later shots, the probability drops greatly down from 1-in24 (4 shots) or 1-in-120 (5 shots). The correlations found should match the scenario of a motorcycle steadily advancing along Houston and Elm. The arguments for this are:
• The difficulty of completing all 3,024 correlation checks in 10 days, hence the need to limiting the checks to the most probable microphone locations the motorcycle most likely would be in at that time.
• The lack on any statement, by Dr. Barger, or in the BBN report, where they argue that the probability of the four shots being in the proper order would be only 1-in-24. They would, of course, omit this obvious argument, if they knew there was an alternative explanation for this apparent order.
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I have already noted the dubious assumptions that the NRC panel had to make to get their feeble 22% probability that random noise caused the dictabelt grassy knoll gunshot, as opposed to the “5 percent or less” probability calculated by Weiss and Aschkenasy (WA).
But it is also important to note that the NRC panel ignored—simply flat-out ignored—a key qualification that WA stipulated regarding their “5% or less” probability of chance: WA stipulated that this calculation was “highly conservative” and that the actual probability of chance was “considerably less” than 5%.
WA explained that their “5% or less” calculation assumed that impulses could only occur in the two intervals in which echoes were observed to occur in the test-firing grassy knoll shot. These two intervals were from 0 to 85 milliseconds and from 275 to 370 milliseconds.
The grassy knoll test shot produced a distinctive pattern in which the echoes arrived in two clusters. The first cluster arrived in the first 85 milliseconds and consisted of echoes from structures facing Elm Street. The first cluster was followed by a gap of 190 milliseconds, corresponding to the open space at the intersection. The second echo cluster arrived in the last 95 milliseconds (275 to 370) and originated with the structures on Houston Street. This is why WA assumed in their analysis that impulses could only occur during the timespan of these two timeframes, i.e., 180 milliseconds.
But, if the dictabelt impulses were not caused by gunfire, then the timespan during which impulses could have occurred more than doubles: it goes from 180 milliseconds to 370 milliseconds. Why? Because there is a 190-millisecond interval between the two intervals of 0-85 and 275-370 milliseconds. Obviously, if you more than double the timespan for impulses to occur, this vastly reduces the probability that random noise caused the dictabelt grassy knoll shot.
Here is how WA explained this in their report:
The high degree of correlation between the impulse [the dictabelt grassy knoll shot] and echo sequences [of the grassy knoll test shot] does not preclude the possibility that the impulses were not the sounds of a gunshot. It is conceivable that a sequence of impulse sounds, derived from non-gunshot sources, was generated with time spacings that, by chance, corresponded within one one-thousandth of a second to those of echoes of a gunshot fired from the grassy knoll. However, the probability of such a chance occurrence is about 5 percent. This calculation represents a highly conservative point of view, since it assumes that impulses can occur only in the two intervals in which echoes were observed to occur, these being the echo-delay range from 0 to 85 milliseconds and the range from 275 to 370 milliseconds. However, if the impulses in the DPD recording were not the echoes of a gunshot, they could also have occurred in the 190-millisecond timespan that separated these two intervals. Taking this timespan into account, the probability becomes considerably less than 5 percent that the match between the recorded impulses and the predicted echoes occurred by chance. (8 HSCA 32)
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This 78% probability is true. . . . [SNIP]
No, it is not true. Dr. Thomas has explained in great detail why it is false. I quoted Dr. Thomas's entire rebuttal to the NRC panel's 78% figure, but you snipped and ignored the rebuttal, and then treated us to more of your diversionary observations and errant speculation.
You pull this stunt all the time: You ignore arguments that you can't explain; you type several paragraphs of irrelevant observations and flawed speculation; and then you pretend that you have dealt with the arguments.
Quote from: Michael T. Griffith on October 13, 2020, 02:50:07 PM
Anyway, in re-reading the NRC panel’s report, I can see why the HSCA acoustical scientists treated it so dismissively. The report does not even mention, much less try to explain, the locational order in the matches between the dictabelt gunshots and the test-firing gunshots. The report does not even mention the fact that the dictabelt gunshot impulse patterns indicate the microphone was moving at the same average speed as the motorcade. The report does not even mention, much less explain, the fact that N-waves not only appear in the dictabelt gunshots when they should, and do not appear when they should not, but that when they appear, they do so in the correct order and interval in relation to the muzzle blast. I mean, the report literally says nothing—not one word—about any of these correlations.
Yes, but I have provided an explanation for this many times, which you ignore. . . . [SNIP]
One, your explanation is patently absurd. Two, I have not ignored your explanation but have responded to it several times, noting that, among other things, it simply ignores the details of the sonar analysis and the fact that the sonar analysis was able to simulate closer microphones and 180 positions.
"But, but, but . . . they didn't check this microphone or that microphone," etc., etc. Why don't you deal with what they did do in the sonar analysis? Why don't you deal with Dr. Thomas's point-by-point refutation of the NRC panel's bogus value assumptions for their 78% probability of chance?
• The lack on any statement, by Dr. Barger, or in the BBN report, where they argue that the probability of the four shots being in the proper order would be only 1-in-24. They would, of course, omit this obvious argument, if they knew there was an alternative explanation for this apparent order.
What??? You still have not read the BBN report, have you?
In point of fact, the BBN scientists were tremendously impressed with the locational correlations between the dictabelt gunshots and the test-firing gunshots. They determined that the probability that chance caused those correlations was “less than 1%.” Figure 22 in the BBN report shows the microphone positions along the motorcycle route where high correlations were obtained. The BBN scientists referred to this figure in explaining why there was less than a 1% probability that chance caused the time-distance correlations. I quote from the BBN report, which you really should read some day:
Even a brief glance at Fig. 22 shows that the microphone locations that correspond to correlations at the three times after the first impulse tend to progress uniformly forward along the motorcade route. This conclusion can be quantified statistically by the chi-square test. If the motorcycle were not moving through Dealey Plaza at the time of the assassination, the distance along the motorcade route would be a meaningless coordinate, and the microphone locations for the correlations that exceed the detection threshold would occur at random. When the chart in Fig. 22 is partitioned into a 2 x 2 table by separating time at 5 sec and distance at 250 ft, we find 1, 6, 8, and 0 correlations in the four sections reading from left to right, top to bottom. But the expected number of correlations to be found in these four sections, if the correlations occurred at random, are 4.2, 2.8, 4.8, 3.2. The value of chi-square for the observed and expected values is equal to 11.4. There is only 1 degree of freedom in this 2 x 2 table, and the probability that this large value of chi-square could occur at random is less than 1%. Therefore, there is little doubt that the distance coordinate is meaningful, and we conclude that the motorcycle was moving through Dealey Plaza and did, in fact, detect the sounds of gunfire. (BBN report, 8 HSCA 104)
And what did the NRC panel have to say about this powerful evidence? They argued that the BBN scientists had erred, that the BBN value of P<0.01 (i.e., less than 1%) should actually be P=0.07 (i.e., 7%), and that therefore the “significance of the layout” indicated by Figure 22 is “considerably reduced” (NRC report, p. 37). Alright, so instead of the probability of chance being less than 1%, the NRC panel said it is 7%.
Now, many readers will say, “Well, okay, but that means the NRC guys admitted that the probability that chance caused those correlations is only 7%, which means the probability that the police tape was recorded by a motorcycle in Dealey Plaza is 93%.” Indeed.
The NRC panel made no effort to explain the significance of the fact that their own calculation found a 93% probability that the locational correlations occurred because the impulse patterns on the police tape were recorded by a motorcycle in Dealey Plaza. In fact, they did not even specifically mention this. They simply noted that they determined the probability of chance was 7% and acted as though they had dealt a strong blow to the BBN report. Granted, a 7% probability of chance is much more than a <1% probability, but it is still an extremely low probability.
On a side note, the BBN report explains that not every recorded shot would have an N-wave (shock wave) in its impulse patterns because the microphone that recorded the shot was not in position to record it; but, if the microphone were in position to record the N-wave, the N-wave would be “a significant part” of the echo pattern:
In Sec. 2, we described how the shock waves generated by rifle bullets would be sufficiently loud at some microphone positions to become a significant part of an echo pattern. The speed of the bullet is important, because it determines the difference in time between perception of the shock waves and perception of the muzzle-blast waves. (BBN report, 8 HSCA 57)
As noted in previous posts, this is exactly what we see in the acoustical evidence: An N-wave appears in those dictabelt shots that were recorded when the motorcycle was in position to record the N-wave, and no N-wave appears in those shots where the motorcycle was not in position to record it (BBN report, 8 HSCA 49-50).
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No, it is not true. Dr. Thomas has explained in great detail why it is false. I quoted Dr. Thomas's entire rebuttal to the NRC panel's 78% figure, but you snipped and ignored the rebuttal, and then treated us to more of your diversionary observations and errant speculation.
You pull this stunt all the time: You ignore arguments that you can't explain; you type several paragraphs of irrelevant observations and flawed speculation; and then you pretend that you have dealt with the arguments.
I am not going to deal with Dr. Thomas who has no support from acoustic experts, not even from his closest allies, for his principle argument, the 1-in-100,000 claim.
One, your explanation is patently absurd. Two, I have not ignored your explanation but have responded to it several times, noting that, among other things, it simply ignores the details of the sonar analysis and the fact that the sonar analysis was able to simulate closer microphones and 180 positions.
"But, but, but . . . they didn't check this microphone or that microphone," etc., etc. Why don't you deal with what they did do in the sonar analysis? Why don't you deal with Dr. Thomas's point-by-point refutation of the NRC panel's bogus value assumptions for their 78% probability of chance?
Not checking for other possibilities is a big deal.
What if, in addition to for correlations of 145.15 with a test shot from the grassy knoll, at Target 3, they also checked the test shot from the TSBD at Target 3.
What if Weiss and Aschkenasy found a strong correlation with a test shot from both the TSBD and the grassy knoll? Just as BBN did with their study.
What if Weiss and Aschkenasy found strong correlations with test shots fired at different targets? Like strong correlations for both Targets 1 and 3, with the same 1963 impulse. Just as BBN did with their study.
What if Weiss and Aschkenasy found strong correlations from two different locations, like within 5 feet of microphone 3 ( 4 ), and within 7 feet of microphone 3 ( 8 ). A strong correlation with the 145.15 impulse with two different microphone locations 40 feet apart. Just as BBN did with their study.
We would conclude that these estimates of getting ‘false alarms’ or ‘false positives’ as being on 5%, or 1-in-100,000, are clearly false.
But Weiss and Aschkenasy did not check for these correlations. They did not have enough time. They were using computers to check for correlations, but they did not have enough time. I am skeptical of this. I think they were afraid of having their own data discredit the conclusions they wanted to come to. But just testing one 1963 impulse, with just one 1978 test shot, they insured that this could not happen.
What??? You still have not read the BBN report, have you?
In point of fact, the BBN scientists were tremendously impressed with the locational correlations between the dictabelt gunshots and the test-firing gunshots. They determined that the probability that chance caused those correlations was “less than 1%.” Figure 22 in the BBN report shows the microphone positions along the motorcycle route where high correlations were obtained. The BBN scientists referred to this figure in explaining why there was less than a 1% probability that chance caused the time-distance correlations. I quote from the BBN report, which you really should read some day:
Yes. I have read this. But no statement about checking for all 3,024 combinations of the seven impulses with the 432 recordings from 1978. Not only do they not say they checked all combinations, they don’t even seem to know how many possible combinations there are. They only refer to 2,592 combinations, not 3,024 combinations. There is no way they did manually check 3,024 combinations, but thought they had only checked 2,592.
Without a knowing which combinations where checked, and which were not, there is no way you or I or anyone can calculate the odds of “finding” the motorcycle seemed to be at the right place. That might only reflect them checking a limited number of microphones for each impulse.
Plus, how much faith can we put into what Dr. Barger said? Below is BBN Exhibit F-367
http://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm
(http://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm)
Now, below, I quote from the same report you quoted from, just a few lines down:
There remain nine correlations that exceeded the detection threshold, and they occur at four different times:
Group 1.137.70 sec -- four correlations with test shots from the TSBD at Targets 1 and 3.*
Group 2.139.27 sec --three correlations with test shots from the TSBD at Target 3.
Group 3.145.15 sec -- one correlation with a test shot from the knoll at Target 3.
Group 4.145.61 sec -- two correlations with test shots from the TSBD at Targets 3 and 4.
*Possibly because of the presence of an overhead sign that interfered with test shots at Target 2, no correlations were found with that target.
Note the inaccuracies of the above paragraph, when compared with F-367.
With impulse 137.70, four correlations were not found from the TSBD and Targets 1 and 3.
Instead three correlations were found from the TSBD and Targets 1 and 3, plus a fourth correlation from the Grassy Knoll and Target 4.
With impulse 139.27, not just three correlations were found from the TSBD with Target 3.
In addition, a fourth correlation was also found from the Grassy Knoll with Target 3. But the BBN would just assume this inconvenient correlation go down the memory hole.
With impulse 145.15, not just one correlation was found from the Grassy Knoll with Target 3.
In addition, two more correlations were also found from the TSBD with Target 3. But again, the BBN would just assume that these inconvenient correlations also go down the memory hole.
With impulse 145.61, two correlations with test shots from TSBD at Targets 3 and 4 were not found.
Instead, three correlations with test shots from TSBD at Targets 2, 3 and 4 were found.
BBN just prunes away at the unwanted correlations that they wish they didn’t find from their final report. This is unacceptable.
Also note the excuse they give for not finding a correlation with the test shot at Target 2. “the presence of an overhead sign that interfered with test shots at Target 2”.
The 1963 microphone can be right behind the motorcycle shield, totally blocking a direct path from the rifle to the microphone. But this still allowing correlations to be found with the rifle location, the target location and the microphone location.
But an overhead sign that is many of dozens of feet from the 1978 rifle, many of dozens of feet from the 1978 microphone, that can block out the sound waves, preventing a correlation from being found. But only when firing at Target 2. Not when firing at Targets 1 or 3.
And what did the NRC panel have to say about this powerful evidence? They argued that the BBN scientists had erred, that the BBN value of P<0.01 (i.e., less than 1%) should actually be P=0.07 (i.e., 7%), and that therefore the “significance of the layout” indicated by Figure 22 is “considerably reduced” (NRC report, p. 37). Alright, so instead of the probability of chance being less than 1%, the NRC panel said it is 7%.
Now, many readers will say, “Well, okay, but that means the NRC guys admitted that the probability that chance caused those correlations is only 7%, which means the probability that the police tape was recorded by a motorcycle in Dealey Plaza is 93%.” Indeed.
The NRC panel made no effort to explain the significance of the fact that their own calculation found a 93% probability that the locational correlations occurred because the impulse patterns on the police tape were recorded by a motorcycle in Dealey Plaza. In fact, they did not even specifically mention this. They simply noted that they determined the probability of chance was 7% and acted as though they had dealt a strong blow to the BBN report. Granted, a 7% probability of chance is much more than a <1% probability, but it is still an extremely low probability.
On a side note, the BBN report explains that not every recorded shot would have an N-wave (shock wave) in its impulse patterns because the microphone that recorded the shot was not in position to record it; but, if the microphone were in position to record the N-wave, the N-wave would be “a significant part” of the echo pattern:
As noted in previous posts, this is exactly what we see in the acoustical evidence: An N-wave appears in those dictabelt shots that were recorded when the motorcycle was in position to record the N-wave, and no N-wave appears in those shots where the motorcycle was not in position to record it (BBN report, 8 HSCA 49-50).
It seems that the motorcycle shield, or the torso of Officer McLain, should interfere with all the “N-waves”.
Finally, I want to return to this question of the extremely limited tests that Weiss and Aschkenasy made. I don’t know, but let’s say they were using computer punch cards. They made:
A. Computer program to compare any 1963 waveform with the theoretical waveform from many positions near a 1978 microphone. This has got to be 99% of the work.
B. 1 or more computer cards to represent the 1978 waveform from the test shot, from the grassy knoll, at target three, recorded from microphone 3 ( 4 ).
C. 1 or more computer cards to represent the 1963 145.15 waveform.
And ran the program to find the best location near microphone 3 ( 4 ) that would have given the best correlation, in theory.
This is fine. Now, after going through all that work, why not go the extra 1% and make:
B. 1 or more computer cards to represent the 1978 waveform from the test shot, from the TSBD, at target three, recorded from microphone 3 ( 4 ).
And run the same program again, this time with the 1978 TSBD waveform.
If this was done, what effect would it have on their final report, if they found a strong correlation for the Grassy Knoll shot, 4 feet up the street from microphone ( 4 ), but also found just as strong a correlation for the shot TSBD shot, 7 feet down the street from the same microphone?
Mr. Griffith generally dodges simple questions, but I will try it again. Never trust anyone who routinely dodges simple questions:
Question 1: What effect would it have had, on Weiss and Aschkenasy final report if they had done this, and found just as strong a correlation near microphone 3 ( 4 ) for the test shot from the TSBD as they did for the test shot from the Grassy Knoll?
I would say it would have been really bad. How could the 145.15 waveform match up with both the Grassy Knoll shot and the TSBD shot?
Question 2: Why didn’t Weiss and Aschkenasy take the extra step, just slightly more work to punch out a few more cards, to run this correlation?
I say it was likely because they feared, consciously or subconsciously, the two-correlation scenario I have described. Do you have a better theory?
By the way, I used to be a computer programmer from that era, so I know that preparing the data to be used was a fraction of the work of writing the computer program itself.
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I am not going to deal with Dr. Thomas who has no support from acoustic experts, not even from his closest allies, for his principle argument, the 1-in-100,000 claim.
LOL! Uh-huh, in other words, you can't refute the cold, hard math of Dr. Thomas's calculation, so you're going to keep using this lame excuse to ignore it.
You accept the NRC panel's claims, even though they have "no support from acoustics experts." In fact, all six of the HSCA acoustical experts rejected the NRC panel's no-gunshots finding and reaffirmed their four-shots finding. But, of course, you don't care, because you want to believe what the NRC panel said.
You accept the claims of amateurs like O'Dell and Myers and Bowles, even though they have "no support from acoustics experts," and even though the only acoustics experts who have studied the dictabelt recording have said it contains four gunshots.
You assume that even although Dr. Barger proof-read Dr. Thomas's 2001 article, Dr. Barger disagrees with the 1 in 100,000 calculation, even though it greatly strengthens the case for Dr. Barger's conclusions! Yeah, makes perfect sense.
You assume that even though Dr. Thomas consulted extensively with Dr. Barger when he wrote the four chapters on the acoustics evidence for his book, Dr. Thomas must have once again failed to mention that, per your theory, Dr. Barger does not agree with his 1 in 100,000 calculation, even though anyone with sufficient math skills can confirm the accuracy of the calculation for themselves.
Not checking for other possibilities is a big deal.
It is a bigger deal that you keep ignoring the fact that your "other possibilities" were ruled out by BBN as false alarms and that the WA sonar analysis proved they were false matches and proved that the match that BBN found had the highest correlation coefficient with the dictabelt grassy knoll shot--i.e., the grassy knoll test shot--was indeed the true match for the dictabelt grassy knoll shot. It is amazing that you just keep ignoring this fact.
What if, in addition to for correlations of 145.15 with a test shot from the grassy knoll, at Target 3, they also checked the test shot from the TSBD at Target 3.
What if Weiss and Aschkenasy found a strong correlation with a test shot from both the TSBD and the grassy knoll? Just as BBN did with their study.
What if Weiss and Aschkenasy found strong correlations with test shots fired at different targets? Like strong correlations for both Targets 1 and 3, with the same 1963 impulse. Just as BBN did with their study.
What if Weiss and Aschkenasy found strong correlations from two different locations, like within 5 feet of microphone 3 ( 4 ), and within 7 feet of microphone 3 ( 8 ). A strong correlation with the 145.15 impulse with two different microphone locations 40 feet apart. Just as BBN did with their study.
This stuff, AGAIN? I say AGAIN: The BBN scientists explained in their report why they determined that the two TSBD matches for the 145.15 impulse pattern were false matches. AGAIN, for one thing, the two TSBD matches had a lower correlation coefficient than did the grassy knoll match. The grassy knoll test shot had the highest correlation coefficient, so, logically and naturally enough, WA conducted their sonar analysis on that test shot instead of the two TSBD test shots, and the sonar analysis proved beyond rational doubt that the grassy knoll test shot was the true match for 145.15.
We would conclude that these estimates of getting ‘false alarms’ or ‘false positives’ as being on 5%, or 1-in-100,000, are clearly false.
No, we would conclude that you have not read the BBN report, that you are determined not to believe the acoustical evidence because it destroys your theory of the shooting, and that you lack either the capacity or the integrity to deal credibly with the HSCA acoustical research.
And, AGAIN, WA pointed out that the probability of chance is actually "considerably less" than 5%, and they explained why this is. They explained that they limited the comparison timespan to two periods that totaled 180 milliseconds because the test-shot impulses only occurred in those two periods, but that if one assumes that random noise caused the correlations, then the comparison timespan should be 370 milliseconds, not 180, which, of course, greatly reduces the probability of chance. I've pointed this out to you four times now, but you just keep ignoring it.
But Weiss and Aschkenasy did not check for these correlations. They did not have enough time. They were using computers to check for correlations, but they did not have enough time. I am skeptical of this. I think they were afraid of having their own data discredit the conclusions they wanted to come to. But just testing one 1963 impulse, with just one 1978 test shot, they insured that this could not happen.
Yes. I have read this. But no statement about checking for all 3,024 combinations of the seven impulses with the 432 recordings from 1978. Not only do they not say they checked all combinations, they don’t even seem to know how many possible combinations there are. They only refer to 2,592 combinations, not 3,024 combinations. There is no way they did manually check 3,024 combinations, but thought they had only checked 2,592.
Without a knowing which combinations where checked, and which were not, there is no way you or I or anyone can calculate the odds of “finding” the motorcycle seemed to be at the right place. That might only reflect them checking a limited number of microphones for each impulse.
Plus, how much faith can we put into what Dr. Barger said? Below is BBN Exhibit F-367
http://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm
(http://mcadams.posc.mu.edu/russ/infojfk/jfk2/f367.htm)
Now, below, I quote from the same report you quoted from, just a few lines down:
Note the inaccuracies of the above paragraph, when compared with F-367.
With impulse 137.70, four correlations were not found from the TSBD and Targets 1 and 3.
Instead three correlations were found from the TSBD and Targets 1 and 3, plus a fourth correlation from the Grassy Knoll and Target 4.
With impulse 139.27, not just three correlations were found from the TSBD with Target 3.
In addition, a fourth correlation was also found from the Grassy Knoll with Target 3. But the BBN would just assume this inconvenient correlation go down the memory hole.
With impulse 145.15, not just one correlation was found from the Grassy Knoll with Target 3.
In addition, two more correlations were also found from the TSBD with Target 3. But again, the BBN would just assume that these inconvenient correlations also go down the memory hole.
With impulse 145.61, two correlations with test shots from TSBD at Targets 3 and 4 were not found. Instead, three correlations with test shots from TSBD at Targets 2, 3 and 4 were found.
BBN just prunes away at the unwanted correlations that they wish they didn’t find from their final report. This is unacceptable.
Also note the excuse they give for not finding a correlation with the test shot at Target 2. “the presence of an overhead sign that interfered with test shots at Target 2”.
The 1963 microphone can be right behind the motorcycle shield, totally blocking a direct path from the rifle to the microphone. But this still allowing correlations to be found with the rifle location, the target location and the microphone location.
But an overhead sign that is many of dozens of feet from the 1978 rifle, many of dozens of feet from the 1978 microphone, that can block out the sound waves, preventing a correlation from being found. But only when firing at Target 2. Not when firing at Targets 1 or 3.
You have once again butchered F-367. I have told you several times that you are blunderingly misreading/misrepresenting F-367, but you just keep on repeating your blundering.
F-367 is Table II in the BBN report. If you would ever break down and read that report, you would discover that the BBN scientists used Figure 22 to help explain Table II/F-367. In referring to Table II/F-367, they said,
It becomes clear upon examination of the weapon, target, and microphone locations for the several echo patterns that passed the correlation detection test at each of the four different times, that some are inconsistent with each other. Thus, some or perhaps all represent false alarms. Deciding which are false alarms was greatly facilitated by plotting the microphone locations for each of the 15 echo patterns against the time on the DPD tape when it correlated highly. This plot appears in Fig. 22, where zero on the time scale is taken to be the time on the DPD tape where high correlations were first detected. (BBN report, 8 HSCA 102)
The BBN scientists then explained why the following matches were false matches/false alarms based on acoustical/time-distance-movement reasons:
137.70, array 2, target 4 (GK test shot)
139.27, array 3, target 2 (GK test shot)
145.15, array 3, target 2 (TSBD test shot)
145.15, array 3, target 3 (TSBD test shot)
145.61, array 3, target 2 (TSBD test shot)
(BBN report, 8 HSCA 105)
Notice that the two TSBD matches for 145.15 that you've been going on and on about were two of the false matches that BBN identified. Did you catch that? You would have known this weeks ago if you had read the BBN report before choosing to attack it. Personally, I don't attack a report until I have read it, but that's just me.
It seems that the motorcycle shield, or the torso of Officer McLain, should interfere with all the “N-waves”.
Any honest person with decent eyesight can look at the bike's positions and see that you must be blind or dishonest to say this. Why do you suppose that the NRC panel, as desperate as they were to nitpick, misrepresent, and reject the acoustical evidence, did not make this argument?
Umm, and I notice that you said nothing about the NRC panel's finding that the probability that chance caused the locational correlations is only 7%. As I pointed to you, and as you quoted back in your reply, the NRC panel said that instead of the BBN probability of chance of <1%, the probability of chance is actually 7%, which, of course, means that there is a 93% probability that the correlations are not due to chance but are due to the impulse patterns having been recorded by a motorcycle in Dealey Plaza.
Finally, I want to return to this question of the extremely limited tests that Weiss and Aschkenasy made. I don’t know, but let’s say they were using computer punch cards. They made:
A. Computer program to compare any 1963 waveform with the theoretical waveform from many positions near a 1978 microphone. This has got to be 99% of the work.
B. 1 or more computer cards to represent the 1978 waveform from the test shot, from the grassy knoll, at target three, recorded from microphone 3 ( 4 ).
C. 1 or more computer cards to represent the 1963 145.15 waveform.
And ran the program to find the best location near microphone 3 ( 4 ) that would have given the best correlation, in theory.
This is fine. Now, after going through all that work, why not go the extra 1% and make:
B. 1 or more computer cards to represent the 1978 waveform from the test shot, from the TSBD, at target three, recorded from microphone 3 ( 4 ).
And run the same program again, this time with the 1978 TSBD waveform.
If this was done, what effect would it have on their final report, if they found a strong correlation for the Grassy Knoll shot, 4 feet up the street from microphone ( 4 ), but also found just as strong a correlation for the shot TSBD shot, 7 feet down the street from the same microphone?
Mr. Griffith generally dodges simple questions, but I will try it again. Never trust anyone who routinely dodges simple questions:
Question 1: What effect would it have had, on Weiss and Aschkenasy final report if they had done this, and found just as strong a correlation near microphone 3 ( 4 ) for the test shot from the TSBD as they did for the test shot from the Grassy Knoll?
I would say it would have been really bad. How could the 145.15 waveform match up with both the Grassy Knoll shot and the TSBD shot?
Question 2: Why didn’t Weiss and Aschkenasy take the extra step, just slightly more work to punch out a few more cards, to run this correlation?
I say it was likely because they feared, consciously or subconsciously, the two-correlation scenario I have described. Do you have a better theory?
By the way, I used to be a computer programmer from that era, so I know that preparing the data to be used was a fraction of the work of writing the computer program itself.
Blah, blah, blah, blah, blah. I have explained to you several times now why WA did not do a sonar analysis on the two TSBD matches for the dictabelt grassy knoll shot: (1) because the grassy knoll test shot had the highest correlation coefficient, (2) because the two TSBD test shots had a lower correlation coefficient than the grassy knoll test shot, (3) because if the solar analysis verified the grassy knoll test shot as the true match for 145.15, this would automatically confirm that the two (lesser-quality) TSBD matches were false alarms.
Not only did the two TSBD matches for 145.15 have a lower correlation coefficient than the grassy knoll match, but the two 145.15 TSBD matches and the 145.61 TSBD match were clearly false alarms based on time-distance-movement analysis, as the BBN scientists explained in their explanation of Table II/F-367:
The second and third entries at 145.15 sec and the third entry at 145.61 sec are false alarms, because the motorcycle would have had to travel at 16 mph to gain the indicated position of only 70 ft behind the limousine at the time of the last shot. The motorcycle noise level (see Fig. 4) decreased by about 10 dB Just 3 sec before the time of the first correlations, indicating a slowing to negotiate the 120° turn onto Elm St. The motorcycle noise level did not increase for the next 13 sec, so it could not have increased speed to 16 mph and maintained it. (BBN report, 8 HSCA 105)
So there is no way that the two 145.15 TSBD matches could be true matches, and the sonar analysis confirmed this already-obvious fact. Are you going to keep claiming that WA should have done a sonar analysis on these two false matches?
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LOL! Uh-huh, in other words, you can't refute the cold, hard math of Dr. Thomas's calculation, so you're going to keep using this lame excuse to ignore it.
I took a course on Calculus and Analytic Geometry in my first year of college. The class had 40 good math students in it. At the end of the quarter, 26 had dropped out and only 14 passed. I had the second highest grade. I was made a tutor to help other college students with their math homework, often helping students with basic algebra courses but sometimes calculus students taking the same course I had passed or was currently taking. But here I am being lectured on how I can’t face the hard math of Dr. Thomas by someone who can’t figure out how to solve one the basic, classic math problems from high school Algebra 1.
You assume that even although Dr. Barger proof-read Dr. Thomas's 2001 article, Dr. Barger disagrees with the 1 in 100,000 calculation, even though it greatly strengthens the case for Dr. Barger's conclusions! Yeah, makes perfect sense.
A perfectly good assumption since Dr. Barger would not remain silent if he agreed with this 1 in 100,000 calculation.
You assume that even though Dr. Thomas consulted extensively with Dr. Barger when he wrote the four chapters on the acoustics evidence for his book, Dr. Thomas must have once again failed to mention that, per your theory, Dr. Barger does not agree with his 1 in 100,000 calculation, even though anyone with sufficient math skills can confirm the accuracy of the calculation for themselves.
Sufficient math skills are not enough. One must know what constants to plug into the equation. Something an acoustic expert would know but an insect expert would not.
And, AGAIN, WA pointed out that the probability of chance is actually "considerably less" than 5%, and they explained why this is. They explained that they limited the comparison timespan to two periods that totaled 180 milliseconds because the test-shot impulses only occurred in those two periods, but that if one assumes that random noise caused the correlations, then the comparison timespan should be 370 milliseconds, not 180, which, of course, greatly reduces the probability of chance. I've pointed this out to you four times now, but you just keep ignoring it.
Yes. The claimed again and again and again that this is so. But they had a chance to give powerful support for this claim, and declined to do so. They could have check for correlations for other test shots. They had the computer program already made for doing so. How much stronger this claim would have been, if they ran this program that was already developed, and discovered:
For impulse 137.70, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the TSBD, at Target 1, for a location within a few feet of microphone 2 ( 5 ). No other strong correlations were found.
For impulse 139.27, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the TSBD, at Target 2, for a location within a few feet of microphone 2 ( 6 ). No other strong correlations were found.
For impulse 145.15, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the Grassy Knoll, at Target 3, for a location within a few feet of microphone 3 ( 4 ). No other strong correlations were found.
For impulse 145.61, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the TSBD, at Target 3, for a location within a few feet of microphone 3 ( 5 ). No other strong correlations were found.
Had this been done, this would not simply be an unsupported claim. This would be a claim with great support from the data.
Instead, all they did was:
For impulse 145.15, the compared one test shot, with one recording, and found one strong correlation, for a shot from the Grassy Knoll, at Target 3. for a location within a few feet of microphone 3 ( 4 ).
So, we don’t know what the odds of finding a “false alarm”, a false positive are. For all we know the odds might be 1-in-100,000, or 1%, or 5%, or maybe a good deal higher, if a lot of locations are tested within a few feet of a microphone.
Let’s say it was 1%. Running this program on all 3,024 combinations might have given us 30 strong correlations. Of which at least 26 would have to be false positives, possibly all 30.
Let’s say it was 5%. Running this program on all 3,024 combinations might have given us 150 strong correlations. Of which at least 146 would have to be false positives, possibly all 150.
Let’s say it was Dr. Thomas’s 1-in-100,000. Running this program on all 3,024 combinations most likely would have given us 4 strong correlations.
If they had run their program for many possible combinations, we would know. Their excuse for not doing so? Lack of time. This is an unbelievable excuse. On par with “The dog ate my homework”. Once the program is written, 99% of the work is done. For about the same amount of time, one could check out 1, 10, 36 or many more combinations. And risk finding clear false positives.
If they were doing a manual check, this would be more believable. Perhaps, by coincidence, they only had time to laboriously check one combination. But these comparisons were done by computer. So, they could have done many more, if they wanted to.
The clear explanation, is they did not want to demonstrate that their procedure will find false positives. And that is why they did the minimum, just compare one 1963 waveform, with one 1978 waveform, for one shot from one location, at one target, recorded at one microphone, so finding contradictory correlations are impossible. So, their study won’t end up with the same obvious flaw the BBN study ended up with.
You have once again butchered F-367. I have told you several times that you are blunderingly misreading/misrepresenting F-367, but you just keep on repeating your blundering.
F-367 is Table II in the BBN report. If you would ever break down and read that report, you would discover that the BBN scientists used Figure 22 to help explain Table II/F-367. In referring to Table II/F-367, they said,
The BBN scientists then explained why the following matches were false matches/false alarms based on acoustical/time-distance-movement reasons:
137.70, array 2, target 4 (GK test shot)
139.27, array 3, target 2 (GK test shot)
145.15, array 3, target 2 (TSBD test shot)
145.15, array 3, target 3 (TSBD test shot)
145.61, array 3, target 2 (TSBD test shot)
(BBN report, 8 HSCA 105)
Notice that the two TSBD matches for 145.15 that you've been going on and on about were two of the false matches that BBN identified. Did you catch that? You would have known this weeks ago if you had read the BBN report before choosing to attack it. Personally, I don't attack a report until I have read it, but that's just me.
Finding false positives is bad. There are no special exceptions. Like “False positives should always to be considered bad, unless the authors of the study tell us to just ignore them”.
Any honest person with decent eyesight can look at the bike's positions and see that you must be blind or dishonest to say this. Why do you suppose that the NRC panel, as desperate as they were to nitpick, misrepresent, and reject the acoustical evidence, did not make this argument?
But we don’t know if the BBN was doing the same thing Weiss and Mr. Aschkenasy, just to a lesser extent. For all we know, they may have, mostly, limited their checking of combinations, that were consistent with a motorcycle moving at 11 mph. So, any correlation they found, which would be a false positive, would be limited to correlations which match the scenario of a motorcycle moving at 11 mph.
Again, I repeat, after over 40 years, Dr. Barger has not given any information on which of the 3,024 combinations they checked manually, over the course of 10 days, and which they did not. And so, we cannot conclude if the correlation of the data with a 11-mph motorcycle was remarkable or exactly as to be expected, even if they were looking at a recording made from the Trade Mart.
And as I said before, to any reader, never trust someone who dodging a few simple questions:
Question 1 for Mr. Griffith:
If the BBN mostly limited their checking for combinations with strong correlations:
Only checked recordings from microphones 2 ( 5 ) and 2 ( 6 ) with impulse 137.70,
only checked recordings from microphones 2 ( 6 ) and 2 ( 7 ) with impulse 139.27,
only checked recordings from microphones 2 ( 10 ) and 2 (11 ) with impulse 140.32,
only checked recordings from microphones 3 ( 3 ) and 3 ( 4 ) with impulse 145.15,
only checked recordings from microphones 3 ( 5 ) and 3 ( 6 ) with impulse 145.61,
would it be a remarkable coincidence that the strong correlations they found would be consistent with a motorcycle moving at 11 mph?
Yes or no?
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I took a course on Calculus and Analytic Geometry in my first year of college. The class had 40 good math students in it. At the end of the quarter, 26 had dropped out and only 14 passed. I had the second highest grade. I was made a tutor to help other college students with their math homework, often helping students with basic algebra courses but sometimes calculus students taking the same course I had passed or was currently taking. But here I am being lectured on how I can’t face the hard math of Dr. Thomas by someone who can’t figure out how to solve one the basic, classic math problems from high school Algebra 1.
A perfectly good assumption since Dr. Barger would not remain silent if he agreed with this 1 in 100,000 calculation.
Sufficient math skills are not enough. One must know what constants to plug into the equation. Something an acoustic expert would know but an insect expert would not.
Yes. The claimed again and again and again that this is so. But they had a chance to give powerful support for this claim, and declined to do so. They could have check for correlations for other test shots. They had the computer program already made for doing so. How much stronger this claim would have been, if they ran this program that was already developed, and discovered:
For impulse 137.70, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the TSBD, at Target 1, for a location within a few feet of microphone 2 ( 5 ). No other strong correlations were found.
For impulse 139.27, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the TSBD, at Target 2, for a location within a few feet of microphone 2 ( 6 ). No other strong correlations were found.
For impulse 145.15, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the Grassy Knoll, at Target 3, for a location within a few feet of microphone 3 ( 4 ). No other strong correlations were found.
For impulse 145.61, they compared it to all the 12 test shots, with all the 36 recordings, and only found one strong correlation, for a shot from the TSBD, at Target 3, for a location within a few feet of microphone 3 ( 5 ). No other strong correlations were found.
Had this been done, this would not simply be an unsupported claim. This would be a claim with great support from the data.
Instead, all they did was:
For impulse 145.15, the compared one test shot, with one recording, and found one strong correlation, for a shot from the Grassy Knoll, at Target 3. for a location within a few feet of microphone 3 ( 4 ).
So, we don’t know what the odds of finding a “false alarm”, a false positive are. For all we know the odds might be 1-in-100,000, or 1%, or 5%, or maybe a good deal higher, if a lot of locations are tested within a few feet of a microphone.
Let’s say it was 1%. Running this program on all 3,024 combinations might have given us 30 strong correlations. Of which at least 26 would have to be false positives, possibly all 30.
Let’s say it was 5%. Running this program on all 3,024 combinations might have given us 150 strong correlations. Of which at least 146 would have to be false positives, possibly all 150.
Let’s say it was Dr. Thomas’s 1-in-100,000. Running this program on all 3,024 combinations most likely would have given us 4 strong correlations.
If they had run their program for many possible combinations, we would know. Their excuse for not doing so? Lack of time. This is an unbelievable excuse. On par with “The dog ate my homework”. Once the program is written, 99% of the work is done. For about the same amount of time, one could check out 1, 10, 36 or many more combinations. And risk finding clear false positives.
If they were doing a manual check, this would be more believable. Perhaps, by coincidence, they only had time to laboriously check one combination. But these comparisons were done by computer. So, they could have done many more, if they wanted to.
The clear explanation, is they did not want to demonstrate that their procedure will find false positives. And that is why they did the minimum, just compare one 1963 waveform, with one 1978 waveform, for one shot from one location, at one target, recorded at one microphone, so finding contradictory correlations are impossible. So, their study won’t end up with the same obvious flaw the BBN study ended up with.
Finding false positives is bad. There are no special exceptions. Like “False positives should always to be considered bad, unless the authors of the study tell us to just ignore them”.
But we don’t know if the BBN was doing the same thing Weiss and Mr. Aschkenasy, just to a lesser extent. For all we know, they may have, mostly, limited their checking of combinations, that were consistent with a motorcycle moving at 11 mph. So, any correlation they found, which would be a false positive, would be limited to correlations which match the scenario of a motorcycle moving at 11 mph.
Again, I repeat, after over 40 years, Dr. Barger has not given any information on which of the 3,024 combinations they checked manually, over the course of 10 days, and which they did not. And so, we cannot conclude if the correlation of the data with a 11-mph motorcycle was remarkable or exactly as to be expected, even if they were looking at a recording made from the Trade Mart.
And as I said before, to any reader, never trust someone who dodging a few simple questions:
Question 1 for Mr. Griffith:
If the BBN mostly limited their checking for combinations with strong correlations:
Only checked recordings from microphones 2 ( 5 ) and 2 ( 6 ) with impulse 137.70,
only checked recordings from microphones 2 ( 6 ) and 2 ( 7 ) with impulse 139.27,
only checked recordings from microphones 2 ( 10 ) and 2 (11 ) with impulse 140.32,
only checked recordings from microphones 3 ( 3 ) and 3 ( 4 ) with impulse 145.15,
only checked recordings from microphones 3 ( 5 ) and 3 ( 6 ) with impulse 145.61,
would it be a remarkable coincidence that the strong correlations they found would be consistent with a motorcycle moving at 11 mph?
Yes or no?
I think we have reached the point where it is obvious that dialogue with you on this issue is a waste of time.
I notice you once again snipped and ignored the fact that even the NRC panel admitted that there is only a 7% probability that the locational correlations are due to chance (random noise).
You finally decided to try to answer the point that WA pointed out that the probability of chance for the grassy knoll shot is "considerably less" than 5%, but your answer is comical. You erroneously claim that they passed up a chance to prove their point and then go off on another "well, they should have considered a, b, c, d, e, etc." diversion. But you ignore the fact that they did prove their point: They pointed out the obvious fact that if you expand the timespan for impulse-echo correlations from 180 milliseconds to 370 milliseconds, obviously this greatly reduces the odds that chance caused the 145.15-test shot correlations.
You are still making the silly argument that Dr. Barger secretly disagrees with Dr. Thomas's 1 in 100,000 calculation, and that Dr. Thomas has been hiding this disagreement all these years. What are you going to do when Dr. Thompson's acoustical section in his upcoming book endorses the 1 in 100,000 calculation, since Dr. Thompson has been working Dr. Barger on the acoustical evidence for years?
You are still making a number of claims that not even the NRC panel stooped so low as to make, such as your silly claim that McClain's torso would have intervened between the sound waves and the microphone, and your equally silly claims that "we don't know this or that" about what BBN and WA did. Maybe YOU don't know what they did, but people who have seriously, honestly studied the BBN and WA materials know what they did.
I notice that you on several occasions you have basically accused BBN and WA of purposely making false claims about how they analyzed the dictabelt recording. Even the NRC panel didn't stoop so low.
Folks, I would hold off on further discussion on this topic until Dr. Thompson's book Last Second in Dallas comes out on December 3. As mentioned, Dr. Thompson has been working with Dr. Barger for the last several years on the acoustical evidence. Dr. Thomas, who has seen the manuscript, tells me that he believes that Dr. Thompson's section on the acoustical evidence will firmly establish beyond any reasonable dispute that the acoustical evidence is valid.
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I think we have reached the point where it is obvious that dialogue with you on this issue is a waste of time.
I notice you once again snipped and ignored the fact that even the NRC panel admitted that there is only a 7% probability that the locational correlations are due to chance (random noise).
But how could the NRC, or anyone else, calculate these odds, without knowing which microphones the BBN manually checked in 10 days, and which did they did not.
If the BBN made 90% of their search for combinations for:
Only checked recordings from microphones 2 ( 5 ) and 2 ( 6 ) with impulse 137.70,
only checked recordings from microphones 2 ( 6 ) and 2 ( 7 ) with impulse 139.27,
only checked recordings from microphones 2 ( 10 ) and 2 (11 ) with impulse 140.32,
only checked recordings from microphones 3 ( 3 ) and 3 ( 4 ) with impulse 145.15,
only checked recordings from microphones 3 ( 5 ) and 3 ( 6 ) with impulse 145.61,
The odds of finding good locational correlations would be considerably more than 7%.
It is possible that the NRC panel 7% probability estimate was based on a faulty assumption. That all 3,024 combinations of the 7 1963 waveforms were manually compared to the 432 1978 waveforms. If this was somehow done, and BBN never claimed to have done this, then the 7% probability estimate sounds reasonable. But I am not going to accept it until I learn what combinations did BBN check and which did they not.
You finally decided to try to answer the point that WA pointed out that the probability of chance for the grassy knoll shot is "considerably less" than 5%, but your answer is comical. You erroneously claim that they passed up a chance to prove their point and then go off on another "well, they should have considered a, b, c, d, e, etc." diversion. But you ignore the fact that they did prove their point: They pointed out the obvious fact that if you expand the timespan for impulse-echo correlations from 180 milliseconds to 370 milliseconds, obviously this greatly reduces the odds that chance caused the 145.15-test shot correlations.
Well, that is the essence of good science. Checking for a, b, c, d, e. As far as I can tell, Weiss and Aschkenasy were only focused on one possibility:
Possibility A: This was a recording made at Dealey Plaza and recorded the sound of gunshots.
And did not consider:
Possibility B: This was a recording not made a Dealey Plaza and did not record the sound of gunshots.
They should use the computer to check for both possibilities.
If they check many combinations of 1963 waveforms with 1978 waveforms, and find contradictions, the same sort of contradictions Dr. Barger and BBN found all too easily, that the same 1963 waveform matched up with both test shots from the TSBD and the Grassy Knoll, this would indicate the correlations they found were weak, were the result of random chance, and Possibility B has the most support.
But, if they do this same check and get results that contradict what the BBN found, and find no such duplicate correlations, all 1963 waveforms only give strong correlations for a shot from one location, at one target, recorded near one microphone, and the target and microphone locations are reasonable, then Possibility A has the most support.
I don’t see Weiss and Aschkenasy doing anything that looks like good science. Checking for more than one hypothesis.
You are still making the silly argument that Dr. Barger secretly disagrees with Dr. Thomas's 1 in 100,000 calculation, and that Dr. Thomas has been hiding this disagreement all these years. What are you going to do when Dr. Thompson's acoustical section in his upcoming book endorses the 1 in 100,000 calculation, since Dr. Thompson has been working Dr. Barger on the acoustical evidence for years?
This would not change my mind in the slightest, since Dr. Josiah Thompson is no more an acoustic expert than Dr. Donald Thomas. What doctors of Philosophy or Entomology have to say one this subject is not of relevance. You need to go get a quote form someone like Dr. Barger.
You are still making a number of claims that not even the NRC panel stooped so low as to make, such as your silly claim that McClain's torso would have intervened between the sound waves and the microphone, and your equally silly claims that "we don't know this or that" about what BBN and WA did. Maybe YOU don't know what they did, but people who have seriously, honestly studied the BBN and WA materials know what they did.
I think it is likely that McLain’s torso would have been in the way for a later shot from the TSBD. Just look at a good ‘acoustic’ map of Dealey Plaza. And remember that Weiss and Aschkenasy said they believed the microphone was mounted on the left side of the motorcycle. Any reader can judge for themselves if it looks likely that Officer McLain’s torso would block a direct line of sight to the TSBD, for the “fifth” shot.
• Note: For this argument, I am accepting BBN’s claim as where Officer McLain was, within green circle 5, even though he was most certainly much further back, where his torso would not block this line of sight.
https://www.maryferrell.org/wiki/images/6/60/Pict_essay_acousticshistory_AcousticMap_lrg.jpg (https://www.maryferrell.org/wiki/images/6/60/Pict_essay_acousticshistory_AcousticMap_lrg.jpg)
And as for your second point, we don’t know which of the 3,024 combinations of 1963 waveforms and 1978 waveforms the BBN manually check for in 10 days. And which they didn’t. They never said.
But if you do know, don’t withhold this from all us. Provide a link to a clear statement from Dr. Barger or the BBN about which combinations were checked.
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A bit more background information on Dr. Thomas might be helpful. In addition to being a USDA entomological research scientist, he is, of necessity, an expert on statistics. Dr. Thomas has authored or co-authored 116 scientific papers in the field of entomology. A number of his published scientific papers have included extensive and complex statistics. Here is a list of his papers:
https://www.researchgate.net/profile/Donald_Thomas6
Of course, Dr. Thomas's 2001 article on the acoustical evidence was published in the peer-reviewed criminal science journal Science & Justice. The article drew international attention, including a favorable review by the Washington Post, and reopened the debate on the acoustical evidence. Here is the article:
http://www.jfklancer.com/pdf/Thomas.pdf
Significantly, when four of the NRC panel members responded to Dr. Thomas's article, four years later, they did *not* challenge Dr. Thomas's 1 in 100,000 calculation! Four years after Dr. Thomas's article appeared, Drs. Ramsey, Horowitz, Chernoff, and Garwin, along with a Dr. Linsker, wrote a response to the article for Science & Justice, and their response was published in the volume 45, number 4, 2005 edition of the journal. Their entire argument was that since they had allegedly proved that the suspect impulse patterns on the police tape did not occur during the assassination, the BBN and WA correlations were all merely coincidences and that therefore they did not need to respond to Dr. Thomas's finding that there was only a 1 in 100,000 chance that the dictabelt grassy knoll shot was not caused by gunfire.
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Lone-gunman theorists frequently cite Michael O'Dell's amateurish and flawed research on the HSCA acoustical evidence. John McAdams carries O'Dell's research on his website. Come to find out that O'Dell has also dabbled in the RFK case and has produced equally flawed "acoustical analysis" in that case.
Mel "Conspiracies Never Happen" Ayton asked O'Dell to analyze the one and only recording of the RFK assassination, a recording made by a journalist named Pruszynski. O'Dell wrote that he was only able to identify six shots on the tape. If the tape contains more than eight shots, then there must have been more than one gunman, because Sirhan's gun could only hold eight bullets (and Sirhan had no chance to reload).
When six acoustical experts examined the Pruszynski tape, five of them determined that it contains at least 10 shots and at least one group of two shots that were fired within 148 milliseconds of each other, far too quickly to have been fired by the same gun.
The five experts were Philip Van Praag, a world-renowned expert on audio recording technology and the man who literally wrote the book on the development of audio recorders; Wes Dooley and Paul Pegas of Audio Engineering Associates in Pasadena, California; Edward Brixen in Copenhagen, Denmark, who is also a ballistics expert; and Phil Spencer Whitehead of the Georgia Institute of Technology in Atlanta, Georgia.
The one acoustical expert who did not find more than eight shots on the tape was Dr. Philip Harrison, who was asked Mel Ayton to analyze the tape. Further investigation revealed that Harrison used a less-than-ideal a copy of the tape, didn't use any of the specialized equipment that Van Praag used, didn't use any of the test or enhanced recordings that Van Praag made of the tape, somehow did not notice either of the 120-150-millisecond double-shot groups, and admitted there were several impulses on the tape whose sources he could not identify. Also, it turned out that Harrison was not even aware of Pruszynski's movements and did not know where the microphone was. It seems that Mel Ayton did not give Harrison all the facts when he asked him to analyze the recording.
Anyway, we are only a little over five weeks from the release of Dr. Josiah Thompson's highly anticipated book Last Second in Dallas, which will include a detailed defense and confirmation of the HSCA acoustical evidence. Dr. Thompson has been working with Dr. James Barger on the acoustical evidence for the last several years.
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A bit more background information on Dr. Thomas might be helpful.
Trust me, nobody cares a xxxx.
You mean you don't.
Lone-gunman theorists frequently cite Michael O'Dell's amateurish and flawed research on the HSCA acoustical evidence.
Mr. Science calling somebody's research amateurish while at the same time repeatedly has failed to support his own fantasy dicta-belt needle jump speaks volumes.
HUH??? I asked you several times to explain why you choose Decker's anomalous crosstalk, which has the largest time offset of any crosstalk event, as your time indicator as opposed to the five time indicators that put the gunfire segment during the assassination, i.e., the Channel 1 12:28 time notation, the Channel 2 12:30 time notation, the Fisher crosstalk, and Curry's two Dealey Plaza transmissions. You ducked this straightforward question every time.
Of course, we both know why you cling to Decker's crosstalk as your time indicator: otherwise, you would have to explain the powerful, intricate correlations between the police tape impulse patterns and the Dealey Plaza test shots. You would need need to start by explaining why even the NRC panel admitted that there is only a 7% probability that chance caused the amazing locational correlations between the dictabelt gunshots and the test-firing gunshots.
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I can pick any cross talk I like as a reference so your repeated nonsense claim tells me you don't even understand what cross talk is, which comes as no surprise.
LOL! Yeah, uh-huh. Shall we list your many comical gaffes that prove you have no clue what you're talking about? Do you remember when you were scoffing at the idea of time offsets? Do you remember when you said you could not understand Herb Blenner's research? Do you remember when you and Elliott claimed that human speech can cause N-waves? (Simple common sense should have told you that since speech does not exceed the speed of sound, there is no way speech can cause N-waves.) Remember? These are just a few examples.
BTW, there's no Fisher cross talk, I already linked to a rebuttal of that claim.
And I cited sources that prove your amateurish link is bogus. Even if we ignore facts and assume for the sake of argument that there is no Fisher crosstalk, what about the four other time indicators: the time notation on Channel 1, the time notation on Channel 2, Curry's "triple underpass" transmission, and Curry's "to the hospital" transmission? The gunshot impulses occur smack dab among these transmissions. But, nah, you ignore all this and cling for dear life to Decker's anomalous crosstalk.
By the way, Dr. Thompson's upcoming book Last Second in Dallas will confirm that Fisher's transmission is crosstalk.
So once again we're stuck with your fantasy needle-jump, which you refuse to back up with facts, which also comes as no surprise.
Uh-huh. You STILL have not explained why you ignore the five time indicators that put the gunshot impulses during the assassination but instead choose Decker's crosstalk as your time indicator. Talk about "fantasy."
I notice you avoided the point that even the NRC panel conceded that there is only a 7% probability that chance caused the locational correlations in the acoustical evidence. That means there's a 93% probability that those correlations exist because the police tape was recorded by a moving microphone in Dealey Plaza.
You see, as the HSCA acoustical experts pointed out, anyone who claims that the dictabelt's suspect impulse patterns were not recorded in Dealey Plaza during the assassination must explain the numerous intricate correlations between the tape's impulse patterns and the Dealey Plaza test-firing impulse patterns.
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Kicking and screaming, polluting the thread with your canned trash over and over.
Your bluff was called and now you're on your own, panicking.
Oh, yes, I'm in full panic mode! Who, pray tell, called my "bluff"? When? How? You guys blunder all over yourselves, write evasive replies when your errors are noted, and then declare yourselves the winners anyway.
Come on, Applied Science Genius, show us that dicta-belt dancing needle YOU claimed could "misplace" cross talk -- ROFL
Uh, hold on, Mr. I Can't Understand Herb Blenner. YOU are saying that the five time indicators that I've cited must be misplaced, because the gunshot impulse patterns occur among them. But you claim that those impulse patterns actually occur at least 60 seconds after the assassination--because, because, because you use Decker's anomalous crosstalk as your time indicator, even though it has the largest time offset of any of the crosstalk events.
I have asked you at least a dozen times to explain why you pick one time indicator over five time indicators, two of which are time notations. You continue to duck that question.
SOMETHING caused the time offsets (you know, the time offsets that you didn't know existed until I proved they did), and SOMETHING caused Decker's crosstalk to occur to occur within seconds of the 12:30 Channel 2 time notation and within seconds of Curry's two Dealey Plaza transmissions, i.e., at least 60 seconds too early on Channel 1. SOMETHING caused those things, whether it was needle displacement or time-warping caused by copying or splicing.
YOUR explanation requires us to believe that all the intricate correlations between the police tape impulse patterns and the test-firing impulse patterns are somehow, someway just an incredible coincidence, when even the NRC panel admitted that the odds of chance causing just the locational correlations are only 7 in 100.
YOUR explanation requires us to ignore the calculation that there is only a 1 in 100,000 chance that the grassy knoll correlations are a coincidence. We all saw what happened when I repeatedly asked Joe Elliott to refute Dr. Thomas's calculation. Whiff. Whiff. Whiff. After making the already-obvious point that the calculation involves assigning values, he then declined to explain why the values that Dr. Thomas chooses are invalid. Yeah, duh, of course the calculation is not just math but math based on selected values. Ok, WHY are the values that Dr. Thomas assigned wrong? In fact, they are absolutely reasonable and irrefutable.
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FYI, the release date for Josiah Thompson's long-awaited book Last Second in Dallas has been pushed back by at least one month. Amazon says it will be published on January 7, but the University Press of Kansas website says it'll be published in February. It is not unusual for a publication date to get pushed back once or twice, especially for a highly anticipated book.