Understanding and Appreciating the HSCA Acoustical Evidence

[Pat Speer]

6 hours ago, Michael Griffith said:

Your comment suggests you have not read the HSCA acoustical materials. There is a huge difference between the HSCA acoustical experts and the other HSCA experts whom you cite. The BBN acoustical scientists were initially skeptical that the police tape contained gunfire. Ditto for Weiss and Aschkenasy. In fact, when Weiss and Aschkenasy first heard the tape, they said they thought someone had to be kidding. The BBN scientists only began to change their minds when they digitized the 5.5-minute open-mic sequence, printed the oscillograph (soundwave graph), and began to analyze the graph. When they analyzed the soundwave graph, they recognized patterns that had N-wave characteristics and knew right away that this finding demanded that they do further testing. 

If you would read the BBN report, the Weiss and Aschkenasy report, and Barger, Weiss, and Aschkenasy's testimony, you would learn that they ran screening tests that were designed to disqualify suspect impulse patterns as much as they were designed to do the opposite. 

If anything, the HSCA acoustics experts can be accused of being too cautious and of understating their case. A prime example of this is the ultra-conservative way that Weiss and Aschkenasy arrived at their 5% probability of chance figure. They made the needlessly conservative assumption that impulses could occur only in the two intervals in which echoes were observed in the field-test grassy knoll shot. This assumption needlessly ignored the fact that if the impulses were not gunfire, they would have been able to occur between those two intervals, adding 190 milliseconds to the timespan for impulses to occur and vastly reducing the probability of chance to far below 5%. 

Weiss and Aschkenasy acknowledged this in their report. The NRC panel, and every critic since then, ignored this key qualification of the 5% figure. 

Weiss and Aschkenasy explained that their “5% or less” calculation assumed that impulses could only occur from 0 to 85 milliseconds and from 275 to 370 milliseconds, because these were the intervals in which echoes occurred in the field-test grassy knoll shot.

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 Weiss and Aschkenasy assumed in their analysis that impulses could only occur during the timespan of these two timeframes, and these timeframes added up to 180 milliseconds. 

But, if the dictabelt impulses were not caused by gunfire, if they were generated by random noise, 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 Weiss and Aschkenasy 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)

Are you ever going to get around to dealing with the correlations between the police tape's impulse patterns and the field-test impulse patterns? AGAIN, okay, if McClain's motorcycle did not record the sounds on the tape, and if the sounds did not occur in Dealey Plaza and even occurred after the assassination, how did those impulse patterns get on the tape? The tape contains N-waves, muzzle blasts, muzzle-blast echoes, windshield-distortion patterns, and only when the microphone was in position to record them. How did these patterns get on the tape? 

If no one could have assembled the bicycle, tell my how the bicycle got assembled. You can repeat over and over and over again that you do not think anyone could have assembled the bicycle. The problem is that we have an assembled bicycle. Just tell me how you think the bicycle got assembled. 

You just don't get it, Michael. it's junk science. It's an old tape with some crackles on it that don't even sound like gunshots, The evidence suggests, moreover, that It was not recorded in Dealey Plaza.

The rest is smoke designed to impress people. We know Olivier, Sturdivan, Alvarez, Guinn, Canning, and Baden, et al, blew smoke. So why is it so hard to imagine that another couple of experts blew smoke? 

The best way to see something is to view it from a variety of angles. Let's assume that instead of a dictabelt, it's a blurry film which is purported to show Oswald firing upon Kennedy. Only...

1. It doesn't actually show Oswald in the sniper's nest window, but instead shows a blurry figure crouching down. 

2. The cameraman credited with taking the footage says he didn't take the footage, and that he wasn't even looking at the sniper's nest at the time of the shooting.

And yet some "experts" have concluded the blurry shape is in fact Lee Harvey Oswald, because they have concluded some combination of dots in the blurry image could only have been created if the camera was pointed at someone who looked exactly like Oswald.

In such case, I think you would agree that these "experts" were agenda-driven, and blowing smoke. 

[Michael Griffith]

Quote

 

Yesterday, Pat Speer said:

It amazes me, moreover, how the same people claiming the HSCA's pathology panel had a bias, and blew smoke, and the HSCA's trajectory expert had a bias, and blew smoke, and the HSCA's NAA expert had a bias, and blew smoke, refuse to accept the possibility the acoustics experts were also blowing smoke, only in a different direction. 

Oh, wait a minute now. You accept many of the HSCA pathology panel's claims. You say they got it right on the back wound's location and on the authenticity of the autopsy photos, even the nakedly impossible brain photos. You have inhaled quite a bit of the smoke they were blowing.

As usual, you are exaggerating and oversimplifying. Many of the HSCA experts also made valid observations. Even the pathology panel correctly noted that the brain photos categorically rule out the EOP entry site, and that the brain photos show a brain with virtually no tissue missing. They also correctly noted that the WC placed the back wound noticeably too high. Some of the outside experts consulted by the pathology panel provided valuable insights into the skull x-rays that the panel found impossible to accept, not because they were wrong but because they contradicted the panel's conclusions about the head wounds.

The HSCA photographic experts correctly--and historically--noted that the Zapruder film shows that JFK was hit at around Z186-190, when Oswald's view of JFK would have been obscured by the oak tree, and that JFK begins to react to this hit at around Z200. 

On 7/2/2023 at 4:22 AM, Pat Speer said:

You just don't get it, Michael. it's junk science. It's an old tape with some crackles on it that don't even sound like gunshots, The evidence suggests, moreover, that It was not recorded in Dealey Plaza.

The rest is smoke designed to impress people. We know Olivier, Sturdivan, Alvarez, Guinn, Canning, and Baden, et al, blew smoke. So why is it so hard to imagine that another couple of experts blew smoke? 

The best way to see something is to view it from a variety of angles. Let's assume that instead of a dictabelt, it's a blurry film which is purported to show Oswald firing upon Kennedy. Only...

1. It doesn't actually show Oswald in the sniper's nest window, but instead shows a blurry figure crouching down. 

2. The cameraman credited with taking the footage says he didn't take the footage, and that he wasn't even looking at the sniper's nest at the time of the shooting.

And yet some "experts" have concluded the blurry shape is in fact Lee Harvey Oswald, because they have concluded some combination of dots in the blurry image could only have been created if the camera was pointed at someone who looked exactly like Oswald.

In such case, I think you would agree that these "experts" were agenda-driven, and blowing smoke. 

Okay, I can see that you are not going to deal with this subject in an objective and credible manner. You simply ignored my point that the HSCA acoustical experts were initially skeptical that the tape contained gunfire. Weiss and Aschkenasy, in particular, were not just skeptical, they were dismissive when they first heard the tape. But you just swept aside this inconvenient fact because you need to assume that they began their analysis ardently wanting to prove the tape contained gunshots. 

Your comment that the police tape merely contains "some crackles on it that don't even sound like gunshots" shows that you do not even understand the basics of the acoustical evidence, much less the intricate and sophisticated aspects of it. I do not believe you have read the BBN report, the Weiss and Aschkenasy report, and the HSCA hearings on the acoustical evidence. No one who has read those materials would make the silly amateurish argument that the acoustical evidence is invalid because the crackles on the tape do not sound like gunshots to the human ear. Even the NRC panel, with as many blunders as they committed, did not make this embarrassingly unscientific argument. One of the first issues the HSCA acoustical scientists addressed (and easily explained) was why the gunshots are not audible to the human ear when you play the tape.

Your blurry-photo analogy is comical in its lack of resemblance to the case for the acoustical evidence. Clearly, you have no intention of trying to explain how the police tape came to contain the impulse patterns of N-waves, muzzle blasts, muzzle-blast echoes, and windshield distortions, and contains them only when the microphone was in position to record them and never when the mike was not in position to do so, not to mention how echo patterns that mirror those of Dealey Plaza got on the tape. 

Regarding the cameraman in your analogy, you again ignore the fact that McLain changed his story and only later claimed that he could not have been the mike with the open mike. Before he knew what he was supposed to say, McLain's description of his movements in the plaza put him in a location that would have enabled him to be in the position indicated by the acoustical analysis. Let us read what he said, under oath, when he first described his movements: 

Mr. CORNWELL. The first exhibit, JFK F-668, on the left, reflects the motorcade from its left side. There is an officer a short distance ahead of the cameraman, a number of cars, and then further down the motorcade, also on the left side, two motorcycles. Do you recognize the street that that was taken on?
Mr. MCLAIN. That looks like it was taken on Houston.
Mr. CORNWELL. Approaching Houston?
Mr. MCLAIN. No; on Main Street, approaching Houston.
Mr. CORNWELL. So then, Houston Street would be where the buildings break apart and you see a lot of sky toward the end of the street; is that correct?
Mr. MCLAIN. Yes, sir.

Mr. MCLAIN. The tree that you see there will be on the opposite
side of Houston.
Mr. CORNWELL. In Dealey Plaza?
Mr. MCLAIN. Yes, sir. You will turn between the tree and the
building on Houston.
Mr. CORNWELL. Can you tell us whether or not the motorcycle officer in the foreground of that picture--the one closest to the cameraman--was you?
Mr. MCLAIN. Yes, sir.
Mr. CORNWELL. Then directing your attention to the next exhibit, F-669, would it be fair to state that that is a photograph taken down Houston Street from approximately the location of the intersection of Main and Houston, looking toward the Texas School Book Depository?
Mr. MCLAIN. Yes, sir.

Mr. CORNWELL. I might state for the record, Mr. Chairman, that in frames just prior to the ones which have been blown up here, it is clear that the cars at the extreme portion of the photograph, away from the photographer, consist of the Presidential limousine, flanked by two motorcycles, and the Secret Service followup car; but you can still see with some clarity in the photograph the Secret Service followup car and the two motorcycles. In other words, the Presidential limousine is right at the corner and turning from Houston onto Elm, and from the School Book Depository.

Mr. CORNWELL. The next two photographs have been placed on the easels out of sequence. May we have those altered just so that they could be viewed with more clarity? The last two-we need to just switch their location. Exhibit F-670 would be several frames after exhibit F-669, also looking down Houston Street, showing essentially the same portion of the motorcade. And then the following exhibit, F-671, would be, again, a few frames later. When viewing the entire film intact, you can then see that within a matter of seconds after the Presidential limousine turns in front of the depository, a police officer riding a motorcycle enters right in front of the photographer--and that is exhibit 671--right onto Houston Street from Main.

Mr. CORNWELL. Can you tell us, Officer McLain, would that have been you?
Mr. MCLAIN. Yes, sir.
Mr. CORNWELL. Do you have a memory of hearing any shots while you were in Dealey Plaza?
Mr. MCLAIN. I only remember hearing one.
Mr. CORNWELL. And approximately where were you when you heard that shot?
Mr. MCLAIN. I was approximately halfway between Main and Elm Streets on Houston.
Mr. CORNWELL. So you would have heard it sometime after the picture was taken in exhibit F-671, the last one on the right?
Mr. MCLAIN. Yes, sir.
Mr. CORNWELL. And before you got to the corner and turned the corner from Houston onto Elm; is that correct?
Mr. MCLAIN. That's correct. . . .

Mr. CORNWELL. I would like to ask you next, what happened after you heard the broadcast from Chief Curry about proceeding to Parkland Hospital?
Mr. MCLAIN . Well, everybody broke and headed for the hospital.
Mr. CORNWELL. At the time that this occurred, you said "proceeding." I take it that means that you revved your engine up and started up at high speed to go toward the hospital?
Mr. MCLAIN. Yes, sir.
Mr. CORNWELL. Do you have a memory of where the Presidential or Vice Presidential limousines were roughly at the time that you caught up with them after hearing Chief Curry's radio signal?
Mr. MCLAIN. They were approximately--well, in front of what is now, where they have the Hyatt House, would be the overpass over Continental.
Mr. CORNWELL. So, in other words, although you speeded up your motorcycle and attempted to catch up to the Presidential and Vice Presidential limousines, it took you until some point up on Stemmons Freeway before you could catch them; is that right?
Mr. MCLAIN. Yes, sir. . . .

Mr. CORNWELL. And with respect to F-675, did you identify that as representing you and another officer on Elm Street?
Mr. MCLAIN. Yes; that's myself and Sergeant Courson. Well, he is now sergeant; he was J. W. Courson at the time.
Mr. CORNWELL. So that last picture we just described, F-675, you identified as appearing to you to represent yourself and Officer Courson, and Courson was at an earlier point in the motorcade, riding behind you, also on the lefthand side?
Mr. MCLAIN. Yes, Sir. (5 HSCA 628-630, 635)

And notice that McLain made none of his later claims about what he supposedly did and saw after he heard gunfire.

McLain also admitted that he normally used Channel 1 and that he did not recall using a different channel that day (contrary to one of his many later false claims):

Mr. CORNWELL. Now had you personally had any occasion on that day, to your memory, to use your radio, to talk through it?
Mr. MCLAIN. No, sir.
Mr. CORNWELL. Do you have a distinct memory of what channel
your radio was set on?
Mr. MCLAIN. It's normally set on channel 1.
Mr. CORNWELL. And do you remember anything differently on that day?
Mr. MCLAIN. No, sir.
Mr. CORNWELL. The answer is no?
Mr. MCLAIN. Nope. (5 HSCA 630)

McLain further acknowledged that his mike frequently got stuck in the open position:

Mr. CORNWELL. Do you know whether or not it would have been possible for your microphone to have been stuck in the open position without your knowledge?
Mr. MCLAIN. Yes, sir; it has been before.
Mr. CORNWELL. Under how many different circumstances in your particular case?
Mr. MCLAIN. I'm scared to say. (5 HSCA 637)

The HSCA report provides a good summary of McLain's testimony:

          He further stated that he was the officer in the photographs taken of the motorcade on Main and Houston Streets, and that at the time of the assassination he would have been in the approximate position of the open microphone near the corner of Houston and Elm, indicated by the acoustical analysis.  He did not recall using his radio during the motorcade nor what channel it was tuned to on that day. He stated it usually was tuned to channel one. The button on his transmitter receiver, he acknowledged, often got stuck in the "on" position when he was unaware of it, but he did not know if it was stuck during the motorcade. (HSCA report, p. 76)

The bottom line about McLain is that you cannot prove that McLain was not in position to record the tape, and I cannot prove that he was. The photographic record simply does not show his location during the shooting sequence. Therefore, we are left to make subjective judgments about where he could and could not have been, based on interpretation of photos and footage that show him before and after the shooting. 

Speculation and deduction about McLain's position, no matter how adamantly stated, cannot invalidate the hard scientific evidence found on the police tape itself. N-waves, muzzle blasts, muzzle-blast echoes, windshield-distortion patterns, echo patterns that mirror a known location's echo-pattern fingerprint, etc., do not just magically appear on recordings out of thin air. These things must be explained by anyone who says the acoustical evidence is invalid. 

Edited July 3, 2023 by Michael Griffith

[Michael Griffith]

If you visit pro-WC websites that discuss the acoustical evidence, you will usually see a link to one of Michael O'Dell's critiques of the acoustical evidence. As I have mentioned, researchers who specialize in the RFK assassination can tell you about the badly flawed research that O'Dell has done on the audio recording of the RFK shooting. 

Mel Ayton, an ardent of opponent of virtually all conspiracy theories, asked O'Dell to analyze the recording of the RFK assassination, which is a tape made by a journalist named Stanislaw Pruszynski. O'Dell wrote that he was only able to identify six shots on the tape. Yet, five audio experts studied the recording and determined that it contains at least 10 shots, which is two more than Sirhan could have fired.

Sirhan's gun could only hold eight bullets, and he had no chance to reload. If more than eight shots were fired, then there must have been a second gunman in the hotel pantry where RFK was killed.

When six audio 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 former Bell Laboratories engineer and a world-renowned expert on audio recording technology 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 Pruszynski tape was Dr. Philip Harrison, who was asked by Ayton to analyze the tape. Harrison found "no more than eight shots." Further investigation revealed that, through no fault of his own, Harrison used a mediocre 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 the two 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 Ayton did not give Harrison all the necessary information when he asked him to analyze the recording. 

One wonders if Peter French was aware of these facts when he endorsed Harrison's analysis. However, contrary to what Ayton claims, French is not an acoustical expert. His field is language and language development, and his firm deals with voice comparison, transcription, and authentication. French spent the first part of his academic career working in child language development, language and education, and conversation analysis. He is a professor in the University of York's Department of Language and Linguistic Science. His published research deals with voice comparison, identifying accents, identifying vowel and phonetic changes, identifying a person's speech rhythms, etc. His bio lists his research interests as "human voice and speech behavior." Ayton makes much of French's endorsement of Harrison's flawed analysis, but French has no expertise or training relevant to the computer analysis of non-voice sounds and the oscillographic characteristics of subaudible non-voice sounds, especially of subaudible gunfire waveform patterns.

The point is: Five experts found at least 10 shots on the recording. Another expert found eight shots. But O'Dell said he could only find six shots. (I might add that O'Dell also claims that the N-wave, muzzle-blast, and muzzle-blast-ehco impulse patterns on the DPD dictabelt recording resulted from human speech.) 

Here is Van Praag's 2011 summary of his analysis of the Pruszynski tape, which he submitted as a sworn statement to the U.S. Central District Court of California at the request of Sirhan's attorneys for their "Reply Brief on the Issue of Actual Innocence":

https://justiceforrfk.com/documents/Sirhan-parole---gunshots-audio-recording-documents.pdf

For those who want more information on the RFK assassination, please excuse this shameless plug of my own website on the subject:

https://sites.google.com/view/the-rfk-assassination/home

Edited July 3, 2023 by Michael Griffith

[Michael Griffith]

On 7/2/2023 at 4:22 AM, Pat Speer said:

 

I mean, the HSCA report used a still from the Dorman film to prove McLain was in the proper position, but that still was taken 20 or more seconds later.  Don Thomas tried to counter this by moving the first shot to a later time. But his claims are equally problematic, as he has McLain traveling something like 4 mph across the plaza, hiding behind this car than that car etc, so there is no photo of him crawling across the plaza.

No, Thomas does not move the first shot to a later time. You are repeating Dale Myers' erroneous claim on this issue. Thomas's time for the first shot comes from the BBN report, which Myers apparently did not bother to read very carefully, if he read it at all.

Below are portions from Don Thomas's articles that deal with the arguments you have made about his research on McLain's position. Your errant claim that Thomas moves the first shot to a later time is one of many incorrect statements you have made about his arguments. I realize you're getting most of these things from Myers' research, which is why many of these portions deal with Myers' arguments.

First, from "The Bike with the Mike" (LINK) :

          From his reconstruction, Myers concludes that the last frame showing Hughes is only one-half second before the first shot, and thus McLain could not have been at the specified location at the time of the first shot without traveling at implausible speeds, in excess of 400 mph.

          Myers uses the Zapruder film as a chronometer for the assassination, but mis-synchronizes the acoustical evidence by placing the shooting one second earlier than it was. Also, Myers’ reconstruction of the motorcade procession is based on the positions of the vehicles that are seen first in the Hughes film and then later in the Zapruder film. But Myers misplaces the vehicles as seen in the Hughes film because he misplaced the position of Mr. Hughes. Myers then compounded the error in placement by over-estimating the speed of the vehicles. Thus, in his reconstruction the vehicles are further north and traveling faster than they really were. This combination of errors results in a timeline which is about 3-1/2 seconds shorter than it would be without the errors. Removing those errors leaves McLain with approximately 4 seconds to cover the 174 ft (requiring a speed of about 25 mph) to reach the specified location.

          One measure of the reliability of Myers' analysis is his use of the term “Epipolar Geometric” in the title.

          The epipolar line is the baseline necessary for the triangulation process used in epipolar geometry to fix the position of object P. The problem is that the key analysis used by Myers involves images taken by Abraham Zapruder and by Robert Hughes. At no time does Zapruder appear in any of the Hughes frames nor at any time does Hughes appear in Zapruder’s film. Hence, there are no epipoles or epipolar lines or epipolar geometry involved in Myers' key analysis, or any other analysis as far as I can tell. Rather, Myers uses line of sight to estimate the positions of the cars in the motorcade, but without the exactitude implied by the use of “epipolar geometry.”

          Myers specifically contends that the HSCA’s acoustical experts found four suspect sounds on the police tapes to match with their test shots (I report five) and that the first synchronizes to Zapruder frame 160 (as opposed to my synchronization of the first shot with Z-175). But Myers’ contention is wrong on both counts. My numbers come directly from the BBN report.

          The correct numbers are found in the BBN report in their Table II on page 101 of HSCA vol. 8, reproduced herein.

          Importantly, the time-history in Table II is the playback time from a tape recording made by the Dallas police. As mentioned in the footnote in Table II, the recording process was about 5% too slow, requiring a simple correction to adjust to real time. A second correction is also cited in the text of the BBN report necessitated by the subsequent detailed analysis by a second laboratory (Weiss & Aschkenasy) which demonstrated that the pattern identified by BBN at 145.15 sec included impulses that preceded slightly those recognized by BBN, placing the onset of this pattern 270 msec (=0.27 seconds) earlier. When these corrections are applied to the times in Table II the four time intervals among the five putative gunshots are 1.65, 1.1, 4.8 and 0.7 sec. Consequently, the time of the first acoustically identified shot synchronizes to Z-frame 175, not 160 as claimed by Myers.

          The values reported in my essays and lectures come directly from the data in the BBN report and thus are entirely in accord with the HSCA acoustical evidence. The discrepancy is not between my analysis and the acoustical evidence, but between the acoustical evidence and the way it was subsequently manipulated using non-acoustical evidence. The acoustical experts were told falsely that the murder weapon could be cycled in 1.6 sec, an error repeated by Myers. This erroneous, non-acoustical evidence, along with some tortured logic, led the HSCA to discard one of the acoustical matches as a false positive. This changed the number of shots from five to four, but this does not affect the timing of the first shot.

          In spite of some claims to the contrary (i.e., Gregg Jaynes) no films depict the positions where the acoustics places the open microphone at the time of the shots. However, one motorcycle, that ridden by H.B. McLain, was in a position in the motorcade both before and after the shooting, such that he might have been in the acoustically required locations. Those required locations, the test microphone positions where the suspect patterns matched to test shots, were distributed in the vicinity of the intersection of Elm and Houston Streets (Fig. 1).

          By referring to the Zapruder film, specifically to the sequence surrounding Z-175, the time of the first shot, one finds that the acoustically predicted location for the motorcycle is out of the camera’s view, blocked by structures and the crowd at the intersection. The motorcade vehicle in the immediate vicinity of the predicted location was the mayor’s car (sixth in the motorcade). Frustratingly, of the first nine cars in the motorcade the only one which is never visible in the Zapruder film happens to be the mayor’s car. But because of Myers’ faulty analysis this significant fact never surfaces. 

          Between Z-frames 200 and 250, Zapruder panned his camera to the right providing a glimpse of the motorcade on Houston Street including views of the 7th, 8th, and 9th cars. Many researchers have searched these frames for any indication of the motorcycle and none has been found. This negative evidence means that at the time of the shooting, McLain’s motorcycle was either in exactly the right place predicted by the acoustical evidence (next to car-6) or much further back (next to car-10), the latter being Myer’s conclusion. This dichotomy, and its implications, was not made clear by Myers.

          The importance of the mayor’s car to the issue can be seen in the analysis by Greg Jaynes. Jaynes’ flawed analysis appears at the http://mcadams.posc.mu.edu/Jaynes/. Jaynes claimed that McLain should have appeared in the uncropped version of the Altgens photo (synchronous with Z-255), and cites the absence as proof that McLain was not in the acoustically required position. But, the mayor’s car is also not visible in the Altgens photo. Jaynes should have provided a map showing, a) Altgens’ cameras scope of view and, b) the acoustically required location of the microphone. Such a map is here provided (Fig. 4) which shows that the required microphone location does not fall within the field of view in the uncropped Altgens photo.      

          Myers has badly misplaced Hughes. Myers places Hughes 15.5 ft west of the center line of Houston Street and 8.8 ft south of the center line of Main Street. The first value is accurate but the second is not. It places Hughes in line with the traffic stripe separating the inner and middle east bound lanes of Main street (and Myers’ illustrations e.g. exhibit 83, show this). Actually Hughes was in line with the traffic stripe separating the middle from the outer lanes, which can be seen in the segment of the Hughes film of the oncoming motorcade on Main Street. This error results in a displacement of approx. 11 ft. from where Myers places him (see Fig. 6 for orientation).

          Through this combination of errors: setting the first shot earlier than it was, displacing the vehicles farther northward than they were, and having them travel faster than they were, Myers lops about 3-1/2 sec off the timeline of events. A precise estimate of the exact amount of time that McLain has between his last filmed position and the time of the first shot may not be attainable because it depends very much on how reliably one can extrapolate the speed of the motorcade. Because at these speeds it can take about two seconds to move one car length, it is clear that over distances of several car lengths any extrapolation is bound to have an ambiguity of at least a second or two. In contrast to Myers’ reconstruction which has the cars moving at a steady 9 mph on Houston Street, I have argued that the motorcade is moving in accordion fashion, slower through the turns than in the straight-aways, and moreover are traveling in a slow and surge mode.

          To put the analysis in proper perspective consider these time estimates. Myers calculates McLain’s speed as he makes the turn from Main on to Houston at 14.7 mph. McLain is last seen at 174 ft from the acoustically required position. At a speed of 10 mph, the equivalent of 15 ft per sec, it would take him about 11 seconds to cover the distance. At 20 mph (=30 ft per sec) he could cover the distance in 5.8 sec. Thus at speeds of 21-29 mph, the distance could be covered in just 3-5 sec. Just from the obvious errors in Myers’ analysis one can see that McLain had the necessary time.

          Although Myers claims that his measurements are consistent among the other films, the other films do not show the same vehicles in the same positions. And his conclusions based on the other films are also questionable. An important example is the Dorman film. The Dorman film shows a police motorcycle approaching the intersection of Elm and Houston at a time approximately 3-6 sec after the fatal shot. The officer could be either H.B. McLain or Jimmy Courson.

          A previous critic has already addressed some of the problems in Myers' identification of the officer as McLain and I would reiterate that Myers does not provide any evidence that would distinguish McLain from Courson. For example, the cop in Dorman has a ticket book visible through the windshield and Myers cited this feature as an identifying character for officer McLain. But Figure 7 shows another motorcade officer (Chaney) with his ticket book in the same position; thus having a ticketbook in this position was certainly not unique to McLain, and there is no information on where Courson kept his ticketbook.

          Myers attempts to refute my argument that the timing of the appearance of the officer in Dorman is consistent with Courson’s account that he saw Mrs. Kennedy and SS Agent Hill on the trunk of the limousine when he rounded the corner of Elm and Houston. Myers claims that this officer does not reach the intersection in time to see that event. But this claim is not supported by his synchronization. 

          Regardless of their memories, if the officer in Dorman is Courson, then McLain has to be in exactly the position required by the acoustical evidence. As mentioned previously, the acoustical evidence requires that the microphone was in the vicinity of the mayor’s car (6th in the motorcade) at the time of the gunfire. Actually, because the acoustical evidence requires the bike with the mike to have an average speed of 11-12 mph during the shooting, the motorcycle is expected to pass the mayor’s car as it rounds the intersection. In the Zapruder film, the only car not seen at any time between the president’s limousine and the tenth car in the motorcade, happens to be the mayor's car.

          Similarly, in the Dorman film, one can see in one sequence, the cars ahead of the SS car (5th in line) and those behind the mayor’s car (6th in line) on Elm Street, but not the space between the mayor’s car and the SS car, which happens to be the position indicated by the acoustical evidence for the location of the open microphone. Hence if the officer in Dorman is Courson, on the motorcycle next behind McLain, the only place McLain could have been is exactly where the acoustical evidence requires (Fig. 9).

From "The Acoustical Evidence in the Kennedy Assassination" (LINK) :

          In the mid-section of the motorcade there were four motorcycle patrolmen: Marion Baker, Clyde Haygood, J.W. Courson and H.B. "Buddy" McLain. Of these, Baker and Haygood stopped to search for the assassins in Dealey Plaza. Because the motorcycle motor noise on the police tape does not stop, only Courson and McLain are viable candidates for the source of the broadcast, if the broadcast originated in Dealey Plaza. In testimony to the House Select Committee on Assassinations, McLain acknowledged that he had a chronic problem with a faulty microphone relay on his unit that caused it to stick open from time to time.

          This photograph (Fig 4) taken by Wilma Bond, shows McLain and Courson on Elm Street in front of the Grassy Knoll where patrolman Bobby Hargis had stopped to search for the assassin. Hargis' motorcycle was parked on the south of the sixth pair of roadstripes from the intersection at Houston Street, just beyond where President Kennedy received the fatal shot. According to Richard Trask [p. 208] the Bond Photo was taken "within 20 sec" of the shooting. However, the scene has to happen later than that. A discontinuous film taken by Mark Bell also shows McLain and Courson passing Hargis. But an earlier sequence shows a witness in the background named Charles Hester rising from the ground. At the sound of gunfire Hester had pushed his wife to the ground and covered her body with his own. Hester is seen standing up in other films, in particular, a newsreel shot by Dave Wiegman.

          Wiegman's film is a clock because it can be connected to the pivotal Zapruder film. A brief instant of the Wiegman film shows the President's limousine approaching the underpass. In the Zapruder film, the President's limousine arrived at the underpass at frame 463, which is 8.2 sec after the head shot. The Wiegman film is 27.3 sec long and the frames showing the limousine approaching the underpass appear 11 sec into the film. Therefore, the Wiegman film begins no later than about 3 sec before the head shot. Towards the end of the film, at sec 26, Hester is seen rising from the ground. Because the frame in the Wiegmann film showing the limousine can occur no later than 8 sec after the head shot, Hester must have stood up no later than 23 sec after the President was shot in the head. Assuming that Bell stopped for about 4-5 sec, allows us to estimate that McLain reached the position shown in the Bond photo at around 27 sec after the head shot.

          The Committee published a frame from the Dorman film showing a motorcycle officer at the corner of Elm and Houston which was supposed to be officer McLain. To the officer's right was an automobile asserted to be Car Number 8 and it was further asserted that this time and location was coincident with the predictions of the acoustical evidence. Both assertions were wrong. In the first place, in order to be in the right place, McLain should have rounded the corner in the proximity of Car-6. It was subsequently realized that the automobile partially visible in the Dorman film was actually the eleventh car in the motorcade and this places the motorcycle well back of where it must be to have the microphone that recorded the assassination gunfire.

          But the officer in the Dorman film is not McLain; it is Clyde Haygood. This can be seen by examination of the newsreel footage taken by Malcolm Couch. This still (Fig 10) is a frame from this newsreel, which from context we can see was taken a few seconds before the Bond photo. Couch's film shows all four of the motorcycle patrolmen at the mid-section of the motorcade. In this single frame we can see three. McLain is way in the distance approaching Hargis's parked motorcycle, Courson is about half way to McLain, and here is Haygood. In the running film one can see Haygood passing Couch on the left. Couch was in the tenth car of the motorcade. To orient the situation I have prepared this plot of the vehicle positions (Fig. 11). Car-10 is at the first road stripe on Elm Street when it was passed by Haygood. This means that Car-11 is at or near the corner and this means that the sequence seen in Couch immediately follows the sequence seen in the Dorman film where Car-11 is approaching the corner. Therefore the motorcycle officer next to Car-11 in the Dorman film has to be Haygood.

Finally, from "Debugging Bugliosi" (LINK) :

          However, one of the salient events in the immediate aftermath of the shooting, one that McLain claims to have seen from his position on Houston Street (in Sneed [No More Silence], p. 163), was Mrs. Kennedy's brief sojourn out onto the trunk of the limousine. Between 3-5 sec after the fatal head shot, a sequence shown in the Zapruder film, Mrs. Kennedy ventured briefly on to the trunk to retrieve a piece of her husband's skull. Given the crowds of people and the structures on the south side of Houston Street, it seems unlikely that McLain could have had a clear view of the event from where he claimed to have been, as opposed to the unobstructed view that he would have had on Elm Street where the acoustical evidence places him.

          More importantly, another motorcycle officer, Jimmy Courson, also saw Mrs. Kennedy on the trunk of the limo, but recalled that he was on Elm street, actually just making the turn on to Elm from Houston at the time. In point of fact, newsreels of the motorcade immediately before and immediately after the shooting show that Courson was several car lengths behind McLain, and thus Courson's account regarding his location directly conflicts with that of McLain. Both officers cannot be correct, and while this doesn't prove that McLain's memory was wrong, it does show how unreliable eyewitness memories of events can be, especially coming scores of years after the event.

          However, in this instance a film taken by Elsie Dorman shows a motorcycle officer turning the corner of Elm and Houston at exactly the same moment that Mrs. Kennedy was on the trunk of the car. Robert Groden originally, and Dale Myers subsequently, assumed that the officer was McLain. But the film lacks any critical detail that would allow one to identify the officer as McLain or Courson though the circumstances of the film (the timing and the other vehicles) are such that it has to be one or the other. So, the truth of the matter is, the filmed evidence is exactly in accord with Courson's account, if it is Courson, and directly contradicts McLain's account no matter who it is. Bugliosi does not discuss this issue, perhaps because of the direct conflict to his star witness.

          For the acoustical evidence to be true, the open microphone had to be on a police motorcycle just ahead of the mayor's car when the Dorman sequence begins. In the Dorman film, there is no motorcycle between the Mayor's car and the cop seen rounding the intersection. If the officer in the Dorman film is Courson, the only place McLain can be at that time, is just ahead of the mayor's car, exactly where the acoustical evidence places the motorcycle with the open microphone.

Whatever one thinks about McLain's location during timeframe in question, at the end of the day the scientific evidence on the police tape itself must be explained by anyone who rejects the HSCA's acoustical analysis.

Edited November 16, 2023 by Michael Griffith

[Michael Griffith]

In dismissing Weiss and Aschkenasy’s finding of a 95-plus-percent probability of a grassy knoll shot, the NRC panel committed the baffling blunder of assuming there were two degrees of freedom associated with the grassy knoll gunman when they did their calculations. But even a layman should have realized that there was only one degree of freedom because the grassy knoll gunman's position could not have changed vertically in relation to the fence, but only horizontally, since moving vertically would have produced a different echo-delay time. Dr. David Scheim (doctorate in mathematics from MIT) caught this error: 

          For example, the critical Weiss-Aschkenasy conclusion of a 95-percent probability of a grassy knoll shot was treated only in a sketchy three-page appendix [in the NRC panel's report] that made one outright error--there was only one degree, not two, of freedom associated with the position of the shooter along the grassy knoll fence. (The Mafia Killed President Kennedy, p. 408)

Dr. Don Thomas elaborates on the NRC panel’s curious error:

          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. (Hear No Evil, p. 631)

Also, I wonder how many of those who cite the NRC panel realize that the panel did not even try to explain the most powerful correlation between the police-tape impulses and the test-firing impulses: the timing-movement correlations, i.e., the fact that the dictabelt's five suspect impulse patterns matched five of the field-test gunshot impulse patterns in the correct order and interval.

They could have matched in numerous irregular sequences, such as 5-1-4-2-3 or 3-5-1-4-2 or 2-5-3-1-4, etc., etc. But they did not. They perfectly matched the order of the field-test impulse patterns: 1-2-3-4-5. The probability that the matching of the order alone is a coincidence is 1 in 120, since there are 120 ways to order five events. Then, add to this improbability the extremely low probability that the matching of the interval is also a coincidence. 

These timing-movement correlations were the correlations that the BBN scientists found most impressive and that most convinced them that the suspect impulse patterns had to be gunshots. Yet, it bears repeating that the NRC panel did not even try to explain these amazing correlations.

Edited July 6, 2023 by Michael Griffith