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

[Paul May]

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.

[Joe Elliott]

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)

[Michael T. Griffith]

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.

[Joe Elliott]

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.

[Joe Elliott]

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]

[Joe Elliott]

Errors in the HSCA report, as shown at:

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

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.

[Michael T. Griffith]

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.