The HSCA Acoustical Evidence: Proof of a Second Gunman in the JFK Assassination

[Joe Elliott]

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

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.

[Michael T. Griffith]

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

[Jerry Freeman]

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.

[Joe Elliott]

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?

[Joe Elliott]

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?

[Joe Elliott]

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.




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.

[Joe Elliott]

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


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.