Acoustic Evidence

[Michael T. Griffith]

You reject my credible, logical responses but that doesn't mean they haven't been given to you......multiple times.
Did she tell them what she saw before or after the shooting? I think we both know the answer to that. I don't know what she saw or what she thought she saw but it's easy to embellish a story to make it seem relevant to the assassination. Her story would have had far more credibility and significance had she told law enforcement about it BEFORE the assassination. That's what I meant when I said she didn't tell law enforcement. She didn't tell them before the shooting when it could have made a difference.
If credibility were a requirement for commenting on the JFK assassination, you would have been banned from every JFK assassination forum decades ago.
Your excuses made no sense.
As long as we are demanding explanations, explain why your conspirators would drive around for several minutes in a small parking lot and then leave. You are the one claiming these cars had some connection to the shooting so the burden is on you to establish that. I have no burden to prove that they were not connected. Once more you have assumed something you cannot prove.
For starters, Lee Bowers' observation that there was no gunman behind the stockade fence at the time he heard the shots.

Despite numerous people rushing to the area immediately after the shooting, no one saw a man with a rifle in the area behind the stockade fence.

There were no wounds to either JFK or JBC that were caused by a frontal shot.

So if someone fired a shot from the GK, he did so without being seen during or immediately after the shooting.
 
The vast majority of earwitnesses, regardless of where they believed the shots came from, said they heard 3 shots which matches the number of spent shell found in the sniper's nest.

The GK shooter left no spent shells.

No bullets were recovered except for the two fire from Oswald's rifle.

No wounds to either JFK or JBC caused by a shot from the GK.

You made a big deal about Oswald missing the whole limo with his first shot. Apparently your GK shooter did the same.
The following website give a good summation of the arguments for an against the acoustic evidence showing a GK shooter. The following passage sums up the situation fairly succinctly:

"Sources do not provide a single, universally accepted resolution; expert opinion remains divided and many critiques focus on timing, statistical assumptions and recording artifacts rather than on the raw waveform matches alone."

Notice I did not resort to MTG's practice of clipping a few words out of context. I quoted an entire sentence and provided a link to the entire article for others to judge.

I've already proved to you in numerous exchanges in this forum that every one of these arguments is either false or misleading or irrelevant. And I notice you again made no effort to explain the facts that validate the HSCA's acoustical findings.

Let's try this: How about if you just answer one straightforward question? Here it is:

If the dictabelt did not record gunfire in Dealey Plaza during the assassination, how did N-waves get on the dictabelt -- not crude, superficial N-waves from random noise but gunfire N-waves with muzzle blasts and muzzle-blast echoes, in the correct order and interval, and only when the microphone was in position to record them?

I'll even give you a big hint: The NRC/NAS panel did not even mention the N-wave evidence, much less try to explain it, even though they knew it was a major item of evidence that the HSCA's acoustical scientists justifiably cited as powerful support for their findings.

Ah, heck, I'll give you another big hint: The Linsker group (Linsker, Garwin, Chernoff, Horowitz, and Ramsey) that responded to Dr. Thomas's 2001 article on the acoustical evidence did not lay a finger on the N-wave evidence either, even though four of them had served on the NRC/NAS panel and thus were well aware that this was a major item of evidence that the panel had ignored.

I'll even give you some study notes to help you answer the question.

Dr. David Scheim, who holds a doctorate in mathematics from MIT:

Moreover, an "N-wave," characteristic of supersonic gunfire, appeared in each dictabelt impulse for which the police microphone was in an appropriate position to detect it, including the recorded sound of the third shot [i.e., 144.9 impulse pattern/the grassy knoll shot]. (The Mafia Killed President Kennedy, 1988, pp. 27-28)

Dr. G. Paul Chambers, a physicist who has worked with NASA, with the Naval Surface Warfare Center, and with the Naval Research Laboratory:

In Dealey Plaza, echoes from gunshot test patterns arrive in two discrete [different] clusters, differing in time by about 190 ms. Echoes originating from structures along Elm Street arrive within 85 ms, while echoes from structures farther back on Houston Street arrive in the last 95 ms of a typical 370-ms-duration test pattern. In addition, a “muzzle blast” is usually prominent at the beginning of a gunshot acoustical pattern, while an N-wave (a shock wave traveling faster than the speed of sound due to the rifle bullet exceeding the sound barrier) arrives prior to the muzzle blast. The waveform identified as the grassy knoll shot is shown in figure 13. The presence of an N-wave in this waveform was consistent with the acoustical signature of a supersonic rifle bullet. (Head Shot: The Science Behind the JFK Assassination, 2010 pp. 101-102)

[John Corbett]

I've already proved to you in numerous exchanges in this forum that every one of these arguments is either false or misleading or irrelevant.

You've declared that many times. We have yet to see the proof.

And I notice you again made no effort to explain the facts that validate the HSCA's acoustical findings.

Unlike you, I don't pretend to be an expert in all these highly technical fields pertaining to the JFKA. i've seen how foolish you make yourself look when you try,

Let's try this: How about if you just answer one straightforward question? Here it is:

If the dictabelt did not record gunfire in Dealey Plaza during the assassination, how did N-waves get on the dictabelt -- not crude, superficial N-waves from random noise but gunfire N-waves with muzzle blasts and muzzle-blast echoes, in the correct order and interval, and only when the microphone was in position to record them?

There are no muzzle blasts on the Dictabelt recording. That much I do know. I know what a muzzle blast from a rifle sounds like and it sounds nothing like the impulses on the recording.

I'll even give you a big hint: The NRC/NAS panel did not even mention the N-wave evidence, much less try to explain it, even though they knew it was a major item of evidence that the HSCA's acoustical scientists justifiably cited as powerful support for their findings.

Apparently, they too recognized those weren't muzzle blasts.

Ah, heck, I'll give you another big hint: The Linsker group (Linsker, Garwin, Chernoff, Horowitz, and Ramsey) that responded to Dr. Thomas's 2001 article on the acoustical evidence did not lay a finger on the N-wave evidence either, even though four of them had served on the NRC/NAS panel and thus were well aware that this was a major item of evidence that the panel had ignored.

They also didn't hear muzzle blasts.

I'll even give you some study notes to help you answer the question.

Dr. David Scheim, who holds a doctorate in mathematics from MIT:

Moreover, an "N-wave," characteristic of supersonic gunfire, appeared in each dictabelt impulse for which the police microphone was in an appropriate position to detect it, including the recorded sound of the third shot [i.e., 144.9 impulse pattern/the grassy knoll shot]. (The Mafia Killed President Kennedy, 1988, pp. 27-28)

Dr. G. Paul Chambers, a physicist who has worked with NASA, with the Naval Surface Warfare Center, and with the Naval Research Laboratory:

In Dealey Plaza, echoes from gunshot test patterns arrive in two discrete [different] clusters, differing in time by about 190 ms. Echoes originating from structures along Elm Street arrive within 85 ms, while echoes from structures farther back on Houston Street arrive in the last 95 ms of a typical 370-ms-duration test pattern. In addition, a “muzzle blast” is usually prominent at the beginning of a gunshot acoustical pattern, while an N-wave (a shock wave traveling faster than the speed of sound due to the rifle bullet exceeding the sound barrier) arrives prior to the muzzle blast. The waveform identified as the grassy knoll shot is shown in figure 13. The presence of an N-wave in this waveform was consistent with the acoustical signature of a supersonic rifle bullet. (Head Shot: The Science Behind the JFK Assassination, 2010 pp. 101-102)

Being a mathematician or a physicist does not qualify one as an expert in acoustics. What we have are conflicting opinions of people who are experts as to whether the Dictabelt recording is of gunshots fired during the assassination. Jurors in both civil and criminal cases are often presented with conflicting expert testimony. They are tasked with determining which side has presented the more credible expert testimony. One of the ways they have of doing that is determining which viewpoint fits the body of evidence as a whole. There is absolutely no other credible evidence of a gunshot on the GK. No bullets were recovered except for the two fired by Oswald's rifle. No discarded shells were found except for the three in the sniper's nest which was on the same floor as Oswald's rifle which was positively matched to the only recovered bullets and shells. Neither JFK nor JBC were hit by shots fired fro anywhere in front of them. A witness with a perfect view of the area behind the stockade fence didn't see a shooter at any time before, during, or after he heard the shots. Neither did any of the people who raced to that area following the shots. In short, their is no credible evidence to corroborate the opinion that the Dictabelt recorded gunshots during the shooting. That makes it easy for me to decide whether to believe the experts who said the recording was of gunshots or the experts who said it was not. 

[Michael T. Griffith]

Quote from: Michael T. Griffith on Yesterday at 05:10:36 PM
And I notice you again made no effort to explain the facts that validate the HSCA's acoustical findings.

Unlike you, I don't pretend to be an expert in all these highly technical fields pertaining to the JFKA. I've seen how foolish you make yourself look when you try.

Objective readers will recognize your comment as both factually wrong and indicative of a juvenile mentality.

Quote from: Michael T. Griffith on Yesterday at 05:10:36 PM
Let's try this: How about if you just answer one straightforward question? Here it is:

If the dictabelt did not record gunfire in Dealey Plaza during the assassination, how did N-waves get on the dictabelt -- not crude, superficial N-waves from random noise but gunfire N-waves with muzzle blasts and muzzle-blast echoes, in the correct order and interval, and only when the microphone was in position to record them?

There are no muzzle blasts on the Dictabelt recording. That much I do know. I know what a muzzle blast from a rifle sounds like and it sounds nothing like the impulses on the recording.

It is hard to overstate the level of abject ignorance this comment reveals. This ignorance is inexcusable because it shows you have not read one word of the reports and testimony that the BBN and Queens College acoustical scientists provided to the HSCA. It is almost hard to know where to start to respond to such discrediting blundering. 

Let's start with the fact that, as the HSCA's acoustical experts explained, you cannot "hear" the muzzle blasts and muzzle-blast echoes on the dictabelt with the naked ear because of the effect of the DPD radio system's Automatic Gain Control (AGC). To analyze any recording made from a radio system with AGC, you must first run the recording through an oscilloscope to produce an oscillogram, i.e., a visual printout of the waveforms of the soundwaves on the recording. Dr. Mark Weiss:

. . . we used a device, an electric device called an oscilloscope, for observing the wave shapes of the sounds that we got when we played back tape recordings, and also a device that enabled us to plot these patterns on paper so that we could examine them in very fine detail. (5 H 558)

The printout (the oscillogram) provides a visual representation of the soundwaves' amplitude, frequency, wavelength, and time/velocity. In an acoustical analysis of a shooting, you can then compare these waveforms with the waveforms of the recording of test shots fired in an onsite reenactment, such as was done in the BBN analysis of the recording of the Kent State shooting to determine the location of the rifles that fired the shots.

The HSCA's acoustical scientists determined that the dictablet contains gunfire N-waves by documenting the virtually identical resemblance between the N-waves of the shots fired in the Dealey Plaza test firing and the impulse patterns on the dictablet, and they also showed that the dictabelt's N-waves occur only when the microphone was in position to record them (5 H 571; 5 H 581; 5 HSCA 609-610; 5 HSCA 676-677: HSCA Report, pp. 74-75). The HSCA report on the presence of an N-wave in the grassy knoll shot (the 144.9 impulse pattern):

In addition, Barger emphasized, the first part of the sequence of impulses identified as a shot from the grassy knoll was marked by an N-wave, a characteristic impulse caused by a supersonic bullet.  The N-wave, also referred to as a supersonic shock wave, travels faster than the noise of the muzzle blast of a gun and therefore arrives at a listening device such as a microphone ahead of the noise of a muzzle blast. The presence of the N-wave was, therefore, a significant additional indication that the third impulse on the police dispatch tape represented gunfire, and, in particular, a supersonic bullet. The weapon may well have been a rifle, since most pistols except for some such as a .44 magnum--fire subsonic bullets.

The N-wave was further substantiation for a finding that the third impulse represented a shot fired in the direction of the President. Had the gun been discharged when aimed straight up or down, or away from the motorcade, no N-wave would have appeared. Of the impulse patterns on the dispatch tape that indicated shots from the book depository, those that would be expected to contain an N-wave, given the location of the vehicle's microphone, did so, further corroborating the conclusion that these impulses did represent supersonic bullets. (HSCA Report, pp. 74-75)

Dr. Weiss on the documentation of supersonic waveforms, i.e., N-waves, on the dictabelt:

Mr. CORNWELL. In addition to the characteristics of the form which you have just described as indicating that the weapon fired a supersonic bullet, was there anything else about the waveforms that you discovered in your analysis?

Mr. WEISS. Yes; there are perhaps two things that are relevant to confirming that what we are dealing with here is not noise but is in fact a sound recording of a bullet, of a gunshot by equipment such as was used by the Dallas police motorcycle men. . . .

You can in, as part of the prediction, you can determine what the general pattern of the shape will be at the microphone as you receive it. Now, for example, if at the microphone, as you receive it, you expect that -- well, let me go back to the blackboard here, if I may.

Now if the muzzle blast came in looking something like this [pointing to the oscillogram], it goes up, it goes down, and then it sort of settles back, then from some of these surfaces you can quite accurately predict that it will do exactly the same sort of thing; let us say that the echo shape will be simply a mirror image replica of the muzzle blast.

Now if this is noise, then there is nothing which says that it has to start out going positive. It could equally, let us say, going upwards [on the oscillogram], the sound could equally, with equal probability, start outgoing this way and comeback this way [on the oscillogram]. But in every one of these instances where we identified an echo as coming back from a flat reflecting surface, it has precisely the correct replication quality when compared to the pattern of the muzzle blast. As I say, for noise, you have no right to expect that sort of thing will happen. It is like saying I have a coin which is going to flip once, and the first time it comes up heads, and thereafter every time it is going to come up heads. It doesn't happen that way. (5 HSCA 581)

Professor Ernest Aschkenasy explaining to Congressman Edgar why the "squiggly lines" on the oscillogram are not the result of random noise:

Mr. ASCHKENASY. I can point out here also these first impulses before the muzzle blast, those are the shock waves, and if you look carefully -- I am sure you cannot look that carefully at that distance -- but if you look at these graphs, because these microphones are located at different positions on the street, the relationship between the shock wave and the muzzle blast changes, and it changes in a predictable manner because the manner in which you expect them to change is related to where the observer, or the microphone, is picking up both the shockwaves and the muzzle blast.

Now, you measure here about on the average of about 14 milliseconds, 14 thousandths of a second delay between the shock wave and the muzzle blast. . . .

If you expand the experiment tape [the recording of the test-firing shots] and take an even better look at it, you find there is a little shock wave echo right in between the shockwave and the muzzle blast, and if you expand the police tape properly, you find similar patterns. (5 HSCA 610)

Quote from: Michael T. Griffith on Yesterday at 05:10:36 PM
I'll even give you a big hint: The NRC/NAS panel did not even mention the N-wave evidence, much less try to explain it, even though they knew it was a major item of evidence that the HSCA's acoustical scientists justifiably cited as powerful support for their findings.

Apparently, they too recognized those weren't muzzle blasts.

Even for you, this is a new height of silliness and self-discreditation. If the NRC/NAS panel members didn't think those were muzzle blasts, why didn't they say so?

As desperate as the panel members were to reject the HSCA's acoustical findings, if they had had any evidence that the dictabelt's waveforms contained no N-waves, they certainly would have said so, because the HSCA's acoustical scientists justifiably identified the dictabelt's N-waves as powerful evidence that the tape was recorded in Dealey Plaza during the assassination.

Quote from: Michael T. Griffith on Yesterday at 05:10:36 PM
Ah, heck, I'll give you another big hint: The Linsker group (Linsker, Garwin, Chernoff, Horowitz, and Ramsey) that responded to Dr. Thomas's 2001 article on the acoustical evidence did not lay a finger on the N-wave evidence either, even though four of them had served on the NRC/NAS panel and thus were well aware that this was a major item of evidence that the panel had ignored.

They also didn't hear muzzle blasts.

Then why didn't they say so? Then why didn't they say, "We see no muzzle blasts in the dictabelt's waveforms, so we don't know what the HSCA's acoustical scientists were looking at when they claimed they confirmed the presence of N-waves on the dictabelt"?

Again, even for you, this is a new height of silliness and self-discreditation.

Linsker et al. didn't lay a finger on the N-wave evidence because they had no answer for it.

Quote from: Michael T. Griffith on Yesterday at 05:10:36 PM
I'll even give you some study notes to help you answer the question.

Dr. David Scheim, who holds a doctorate in mathematics from MIT:

Moreover, an "N-wave," characteristic of supersonic gunfire, appeared in each dictabelt impulse for which the police microphone was in an appropriate position to detect it, including the recorded sound of the third shot [i.e., 144.9 impulse pattern/the grassy knoll shot]. (The Mafia Killed President Kennedy, 1988, pp. 27-28)

Dr. G. Paul Chambers, a physicist who has worked with NASA, with the Naval Surface Warfare Center, and with the Naval Research Laboratory:

In Dealey Plaza, echoes from gunshot test patterns arrive in two discrete [different] clusters, differing in time by about 190 ms. Echoes originating from structures along Elm Street arrive within 85 ms, while echoes from structures farther back on Houston Street arrive in the last 95 ms of a typical 370-ms-duration test pattern. In addition, a “muzzle blast” is usually prominent at the beginning of a gunshot acoustical pattern, while an N-wave (a shock wave traveling faster than the speed of sound due to the rifle bullet exceeding the sound barrier) arrives prior to the muzzle blast. The waveform identified as the grassy knoll shot is shown in figure 13. The presence of an N-wave in this waveform was consistent with the acoustical signature of a supersonic rifle bullet. (Head Shot: The Science Behind the JFK Assassination, 2010 pp. 101-102)

Being a mathematician or a physicist does not qualify one as an expert in acoustics. What we have are conflicting opinions of people who are experts as to whether the Dictabelt recording is of gunshots fired during the assassination.

Umm, you realize that six of the 12 NRC/NAS panel members were physicists, right? You realize that four of them were engineers, not even electrical engineers but just regular engineers, right? You realize that one of them was a statistician, and that another one of them was a computer scientist, right? Right? In short, six physicists, four regular engineers, one statistician, and one computer scientist, and not one of them had ever worked or published in the field of acoustical science.

So by your own standard, not one of the NRC/NAS panel members was qualified "as an expert in acoustics." You just royally shot your already-flimsy case in the foot.

And you realize the Linsker, who spearheaded the 2005 reply to Dr. Thomas's 2001 article, is an MD who got a degree in physics and who was mainly known for his work with IBM's Watson project and his work on neural networks and medical informatics, and whose published articles deal with such topics as "Memory and Learning in Biological Brains and Computers," "Far‐ultraviolet laser ablation of atherosclerotic lesions," "Ultraviolet-laser ablation of skin," and "Controlled photoetching of animal tissue by far-ultraviolet (193-nm) laser radiation," right?

Could this be why Linsker's group conducted such a badly flawed PCC test?

Jurors in both civil and criminal cases are often presented with conflicting expert testimony. They are tasked with determining which side has presented the more credible expert testimony. One of the ways they have of doing that is determining which viewpoint fits the body of evidence as a whole. There is absolutely no other credible evidence of a gunshot on the GK. No bullets were recovered except for the two fired by Oswald's rifle. No discarded shells were found except for the three in the sniper's nest which was on the same floor as Oswald's rifle which was positively matched to the only recovered bullets and shells. Neither JFK nor JBC were hit by shots fired from anywhere in front of them. A witness with a perfect view of the area behind the stockade fence didn't see a shooter at any time before, during, or after he heard the shots. Neither did any of the people who raced to that area following the shots. In short, their is no credible evidence to corroborate the opinion that the Dictabelt recorded gunshots during the shooting.

Repeating these lame arguments won't improve them. People who have read our previous exchanges in this forum will see that I have refuted every single one of these arguments, but you just keep repeating them and saying nothing about the contrary facts I've cited against them.

"Extra Bullets and Missed Shots in Dealey Plaza" Documents that more than three shots were fired and that some of the shots could not have come from the alleged lone gunman.

Doug Horne replies to John Tunheim, James Carville and Al Hunt A good summary of some of the evidence of a grassy knoll gunman.

"Was There a Grassy Knoll Shooter? Part 1
"Was There a Grassy Knoll Shooter? Part 2
An excellent two-part video presentation on some of the evidence of a grassy knoll gunman.

That makes it easy for me to decide whether to believe the experts who said the recording was of gunshots or the experts who said it was not.

In other words, you're choosing to ignore the fact (1) that the 11 experts who determined the dictabelt contains gunfire were all acoustical scientists, and (2) that not one of the experts you're choosing to believe was an acoustical scientist. In short, in judging the acoustical evidence, you're taking the word of scientists who were not acoustical experts over the word of scientists who were acoustical experts.

So all of your whining about quoting experts who are speaking outside of their field goes out the window, hey?

Again, the 11 acoustical scientists who worked on the HSCA's acoustical evidence were BBN scientists James E. Barger, Scott P. Robinson, Edward C. Schmidt, Jared J. Wolf, Joseph F. Colaruotolo, Daniel N. Kalikow, Nancy M. McMahon, Theodore L. Rhyne, and Leo A. Sledjeski, and Queens College scientists Mark Weiss and Ernest Aschkenasy. (Note to readers: In a previous reply, I included Ali Ghozati as one of the Queens College acoustical scientists, but I'm omitting him here because I've been unable to confirm that he was in fact an acoustical scientist. In that same reply, I accidentally omitted BBN acoustical scientist Joseph F. Colaruotolo, so I'm now including him.)

Finally, I think it is worth repeating that the NRC/NAS panel admitted (1) that they admitted they found a 93% probability that the timing-movement correlations identified by the BBN scientists occurred because the dictabelt recorded gunfire in Dealey Plaza during the assassination, and (2) that they admitted they found a 77.7% probability that the 144.9 impulse pattern was in fact gunfire from the grassy knoll. In your first reply in this thread, you cited an article by (of all people) Dale Myers that relies heavily on the NRC/NAS panel's report, yet neither you nor Myers nor any of the other amateur Internet hacks who attack the acoustical evidence has yet to address these two key admissions by the NRC/NAS panel. 
 

[John Corbett]

Objective readers will recognize your comment as both factually wrong and indicative of a juvenile mentality.

It is hard to overstate the level of abject ignorance this comment reveals. This ignorance is inexcusable because it shows you have not read one word of the reports and testimony that the BBN and Queens College acoustical scientists provided to the HSCA. It is almost hard to know where to start to respond to such discrediting blundering. 

I've read them. I just didn't believe them.

Let's start with the fact that, as the HSCA's acoustical experts explained, you cannot "hear" the muzzle blasts and muzzle-blast echoes on the dictabelt with the naked ear because of the effect of the DPD radio system's Automatic Gain Control (AGC). To analyze any recording made from a radio system with AGC, you must first run the recording through an oscilloscope to produce an oscillogram, i.e., a visual printout of the waveforms of the soundwaves on the recording. Dr. Mark Weiss:

. . . we used a device, an electric device called an oscilloscope, for observing the wave shapes of the sounds that we got when we played back tape recordings, and also a device that enabled us to plot these patterns on paper so that we could examine them in very fine detail. (5 H 558)

The printout (the oscillogram) provides a visual representation of the soundwaves' amplitude, frequency, wavelength, and time/velocity. In an acoustical analysis of a shooting, you can then compare these waveforms with the waveforms of the recording of test shots fired in an onsite reenactment, such as was done in the BBN analysis of the recording of the Kent State shooting to determine the location of the rifles that fired the shots.

The HSCA's acoustical scientists determined that the dictablet contains gunfire N-waves by documenting the virtually identical resemblance between the N-waves of the shots fired in the Dealey Plaza test firing and the impulse patterns on the dictablet, and they also showed that the dictabelt's N-waves occur only when the microphone was in position to record them (5 H 571; 5 H 581; 5 HSCA 609-610; 5 HSCA 676-677: HSCA Report, pp. 74-75). The HSCA report on the presence of an N-wave in the grassy knoll shot (the 144.9 impulse pattern):

In addition, Barger emphasized, the first part of the sequence of impulses identified as a shot from the grassy knoll was marked by an N-wave, a characteristic impulse caused by a supersonic bullet.  The N-wave, also referred to as a supersonic shock wave, travels faster than the noise of the muzzle blast of a gun and therefore arrives at a listening device such as a microphone ahead of the noise of a muzzle blast. The presence of the N-wave was, therefore, a significant additional indication that the third impulse on the police dispatch tape represented gunfire, and, in particular, a supersonic bullet. The weapon may well have been a rifle, since most pistols except for some such as a .44 magnum--fire subsonic bullets.

I know this is not true. Many common handgun loads such as 9mm, .38 Special, 40 S&W produce muzzle velocities greater than the speed of sound. It depends primarily on the loads and the barrel length. A longer barrel produces higher muzzle velocities.

The N-wave was further substantiation for a finding that the third impulse represented a shot fired in the direction of the President. Had the gun been discharged when aimed straight up or down, or away from the motorcade, no N-wave would have appeared. Of the impulse patterns on the dispatch tape that indicated shots from the book depository, those that would be expected to contain an N-wave, given the location of the vehicle's microphone, did so, further corroborating the conclusion that these impulses did represent supersonic bullets. (HSCA Report, pp. 74-75)[/font]

Dr. Weiss on the documentation of supersonic waveforms, i.e., N-waves, on the dictabelt:

Mr. CORNWELL. In addition to the characteristics of the form which you have just described as indicating that the weapon fired a supersonic bullet, was there anything else about the waveforms that you discovered in your analysis?

Mr. WEISS. Yes; there are perhaps two things that are relevant to confirming that what we are dealing with here is not noise but is in fact a sound recording of a bullet, of a gunshot by equipment such as was used by the Dallas police motorcycle men. . . .

You can in, as part of the prediction, you can determine what the general pattern of the shape will be at the microphone as you receive it. Now, for example, if at the microphone, as you receive it, you expect that -- well, let me go back to the blackboard here, if I may.

Now if the muzzle blast came in looking something like this [pointing to the oscillogram], it goes up, it goes down, and then it sort of settles back, then from some of these surfaces you can quite accurately predict that it will do exactly the same sort of thing; let us say that the echo shape will be simply a mirror image replica of the muzzle blast.

Now if this is noise, then there is nothing which says that it has to start out going positive. It could equally, let us say, going upwards [on the oscillogram], the sound could equally, with equal probability, start outgoing this way and comeback this way [on the oscillogram]. But in every one of these instances where we identified an echo as coming back from a flat reflecting surface, it has precisely the correct replication quality when compared to the pattern of the muzzle blast. As I say, for noise, you have no right to expect that sort of thing will happen. It is like saying I have a coin which is going to flip once, and the first time it comes up heads, and thereafter every time it is going to come up heads. It doesn't happen that way. (5 HSCA 581)

Professor Ernest Aschkenasy explaining to Congressman Edgar why the "squiggly lines" on the oscillogram are not the result of random noise:

Mr. ASCHKENASY. I can point out here also these first impulses before the muzzle blast, those are the shock waves, and if you look carefully -- I am sure you cannot look that carefully at that distance -- but if you look at these graphs, because these microphones are located at different positions on the street, the relationship between the shock wave and the muzzle blast changes, and it changes in a predictable manner because the manner in which you expect them to change is related to where the observer, or the microphone, is picking up both the shockwaves and the muzzle blast.

Now, you measure here about on the average of about 14 milliseconds, 14 thousandths of a second delay between the shock wave and the muzzle blast. . . .

If you expand the experiment tape [the recording of the test-firing shots] and take an even better look at it, you find there is a little shock wave echo right in between the shockwave and the muzzle blast, and if you expand the police tape properly, you find similar patterns. (5 HSCA 610)

Even for you, this is a new height of silliness and self-discreditation. If the NRC/NAS panel members didn't think those were muzzle blasts, why didn't they say so?

As desperate as the panel members were to reject the HSCA's acoustical findings, if they had had any evidence that the dictabelt's waveforms contained no N-waves, they certainly would have said so, because the HSCA's acoustical scientists justifiably identified the dictabelt's N-waves as powerful evidence that the tape was recorded in Dealey Plaza during the assassination.

Then why didn't they say so? Then why didn't they say, "We see no muzzle blasts in the dictabelt's waveforms, so we don't know what the HSCA's acoustical scientists were looking at when they claimed they confirmed the presence of N-waves on the dictabelt"?

As I said, I heard no muzzle blasts one the recording. I don't doubt there are some egghead scientists who have interpreted the impulses on the recording to have been caused by muzzle blasts. I also know there are other egghead scientists who dispute those interpretations. I wouldn't pretend to have the scientific understanding to determine which group of eggheads came to the right answer. When I read the techno-babble, all I do is roll my eyes and so "no (bleep)?" What I can do is compare the conflicting findings of these experts with the body of evidence as a whole to determine which is the most compelling opinion. If there was a shooter on the GK, why did nobody see him (her?) before, during, or after the shooting. Why is there no physical evidence of a shot having been fired from the GK. Neither of the victims were hit by a frontal shot. No bullets or shells were recovered except for those positively matched to Oswald's rifle. Simply put, there is no other compelling evidence of a shot from the GK. In addition, by piecing together the photographic evidence, Myers proved that the motorcycle believed to have recorded the shooting through a stuck open microphone was not in the location the acoustics teams said he needed to be for their findings to be valid. All of this is why I believe the acoustics team simply misinterpreted the data.

I did a search for conflicting opinions regarding what the acoustic evidence shows:

"Scientists Who Disputed the BBN Findings on the Grassy Knoll Shot
The Bolt, Beranek and Newman (BBN) team, led by James E. Barger, analyzed the Dallas Police Department’s Dictabelt recording of Channel 1 during the Kennedy assassination. They found four impulse patterns that resembled gunshots, with a 50% probability that one came from the grassy knoll
Kennedy Assassination Home Page
Kennedy Assassination Home Page
+1
. This uncertainty led the House Select Committee on Assassinations (HSCA) to hire Mark R. Weiss and Ernest Aschkenasy to refine the analysis. Weiss and Aschkenasy concluded there was a 95% probability that the shot originated from the grassy knoll
Kennedy Assassination Home Page
Kennedy Assassination Home Page
+1
.

However, the U.S. Justice Department, instead of further investigation, commissioned the National Research Council (NRC) of the National Academy of Sciences to review the evidence. The NRC panel (often referred to as the NAS Committee on Ballistic Acoustics) disputed the HSCA’s conclusions, claiming there was no scientific proof of a grassy knoll shot and that the acoustical evidence did not establish a high probability of a second gunman
jfk.hood.edu
jfk.hood.edu
+1
.

The NRC’s findings were criticized by independent researchers such as W. Anthony Marsh, who argued the panel was biased, misapplied methods, and failed to conduct the necessary tests to refute the HSCA’s work
Archive
Archive
. Marsh’s 1983 Rebuttal to Ramsey detailed errors in the NAS report and reaffirmed the accuracy of the HSCA’s acoustic analysis.

In summary:

BBN (Bolt, Beranek and Newman) – found 50% probability of grassy knoll shot.

Weiss & Aschkenasy – found 95% probability of grassy knoll shot.

NRC/NAS Committee on Ballistic Acoustics – disputed the findings, claimed no proof of grassy knoll shot.

W. Anthony Marsh – independent critic of the NRC/NAS panel, argued their conclusions were invalid due to bias and methodological flaws [/quote]"

I had to laugh when I saw one of the counter-dissenters was none other than Tony Marsh. That is almost as bad as having Michael T. Griffith providing evidence to support the cause of conspiracy.

Again, even for you, this is a new height of silliness and self-discreditation.

Linsker et al. didn't lay a finger on the N-wave evidence because they had no answer for it.

In your humble opinion.

Umm, you realize that six of the 12 NRC/NAS panel members were physicists, right? You realize that four of them were engineers, not even electrical engineers but just regular engineers, right? You realize that one of them was a statistician, and that another one of them was a computer scientist, right? Right? In short, six physicists, four regular engineers, one statistician, and one computer scientist, and not one of them had ever worked or published in the field of acoustical science.

What they disputed was the scientific method used by BBN, something scientists in all fields should know something about.

So by your own standard, not one of the NRC/NAS panel members was qualified "as an expert in acoustics." You just royally shot your already-flimsy case in the foot.

Not really

And you realize the Linsker, who spearheaded the 2005 reply to Dr. Thomas's 2001 article, is an MD who got a degree in physics and who was mainly known for his work with IBM's Watson project and his work on neural networks and medical informatics, and whose published articles deal with such topics as "Memory and Learning in Biological Brains and Computers," "Far‐ultraviolet laser ablation of atherosclerotic lesions," "Ultraviolet-laser ablation of skin," and "Controlled photoetching of animal tissue by far-ultraviolet (193-nm) laser radiation," right?

No (bleep)!

Could this be why Linsker's group conducted such a badly flawed PCC test?

Repeating these lame arguments won't improve them. People who have read our previous exchanges in this forum will see that I have refuted every single one of these arguments, but you just keep repeating them and saying nothing about the contrary facts I've cited against them.

You should check a thesaurus. They are free online. You'd find out that disputed doesn't mean the same as refuted.  Mostly what you did is dispute and assume that you have refuted.

"Extra Bullets and Missed Shots in Dealey Plaza" Documents that more than three shots were fired and that some of the shots could not have come from the alleged lone gunman.

Doug Horne replies to John Tunheim, James Carville and Al Hunt A good summary of some of the evidence of a grassy knoll gunman.

"Was There a Grassy Knoll Shooter? Part 1
"Was There a Grassy Knoll Shooter? Part 2
An excellent two-part video presentation on some of the evidence of a grassy knoll gunman.

In other words, you're choosing to ignore the fact (1) that the 11 experts who determined the dictabelt contains gunfire were all acoustical scientists, and (2) that not one of the experts you're choosing to believe was an acoustical scientist. In short, in judging the acoustical evidence, you're taking the word of scientists who were not acoustical experts over the word of scientists who were acoustical experts.

So all of your whining about quoting experts who are speaking outside of their field goes out the window, hey?

Again, the 11 acoustical scientists who worked on the HSCA's acoustical evidence were BBN scientists James E. Barger, Scott P. Robinson, Edward C. Schmidt, Jared J. Wolf, Joseph F. Colaruotolo, Daniel N. Kalikow, Nancy M. McMahon, Theodore L. Rhyne, and Leo A. Sledjeski, and Queens College scientists Mark Weiss and Ernest Aschkenasy. (Note to readers: In a previous reply, I included Ali Ghozati as one of the Queens College acoustical scientists, but I'm omitting him here because I've been unable to confirm that he was in fact an acoustical scientist. In that same reply, I accidentally omitted BBN acoustical scientist Joseph F. Colaruotolo, so I'm now including him.)

Finally, I think it is worth repeating that the NRC/NAS panel admitted (1) that they admitted they found a 93% probability that the timing-movement correlations identified by the BBN scientists occurred because the dictabelt recorded gunfire in Dealey Plaza during the assassination, and (2) that they admitted they found a 77.7% probability that the 144.9 impulse pattern was in fact gunfire from the grassy knoll. In your first reply in this thread, you cited an article by (of all people) Dale Myers that relies heavily on the NRC/NAS panel's report, yet neither you nor Myers nor any of the other amateur Internet hacks who attack the acoustical evidence has yet to address these two key admissions by the NRC/NAS panel.

So says our "amateur Internet hack".

I posted this article before but will do so again.

https://factually.co/fact-checks/justice/forensic-acoustic-studies-since-hsca-single-shooter-51b4c1

The final sentence pretty much sums up the veracity of the acoustics evidence:
"a minority of researchers continue to claim acoustic support for a grassy‑knoll shot but their conclusions remain disputed in peer and government reviews."

[Michael T. Griffith]

I've read them. I just didn't believe them. I know this is not true. Many common handgun loads such as 9mm, .38 Special, 40 S&W produce muzzle velocities greater than the speed of sound. It depends primarily on the loads and the barrel length. A longer barrel produces higher muzzle velocities.

You seem to forget that we're talking about handguns in 1963. Anyway, regardless of the weapon, supersonic is supersonic. The HSCA's acoustical experts proved scientifically that the dictabelt contains N-waves caused by supersonic gunfire.

The NRC/NAS panel members knew this, and they knew they couldn't explain it away, so they just ignored it. Ditto for Linsker. If those guys had had even a remotely plausible alternative explanation for the precise N-wave characteristics in two of the dictabelt's impulse patterns, they would have said so. 

As I said, I heard no muzzle blasts one the recording.

Of course you didn't, because the DPD radio system had an AGC circuit! This is just comically dumb. The HSCA's acoustical experts explained this to everyone's satisfaction way back in 1978. Even the two clueless dissenting HSCA congressmen who were determined to reject the acoustical evidence did not make this silly argument. And, needless to say, neither the NRC/NAS panel nor Linsker was foolish enough to make this idiotic argument either.

But, not surprisingly, here you are repeating it, even after I explained why the muzzle blasts and their echoes are not audible to the naked ear. 

I don't doubt there are some egghead scientists who have interpreted the impulses on the recording to have been caused by muzzle blasts. I also know there are other egghead scientists who dispute those interpretations.

No, no, no. You know this is false. Neither the NRC/NAS panel members nor Linsker disputed the presence of gunfire N-waves on the dictabelt. They didn't even so much as say "we don't believe there are gunfire N-waves on the dictabelt." They ducked the N-wave evidence entirely because they knew that if they disputed it, they would have to explain why. They simply ignored it, even though they knew the HSCA's acoustical scientists had justifiably cited it as powerful scientific evidence that dictabelt recorded gunfire.

You are not willing to be candid and credible on the N-wave evidence because you are pathologically determined to deny any evidence that refutes your theory of the shooting, even if the evidence is hard scientific evidence based on known principles and methods of acoustical science. 

When I read the techno-babble, all I do is roll my eyes and so "no (bleep)?"

I don't doubt that for a minute. I'm sure that Weiss and Aschkenasy's explanations flew right over your head, even though they were given in fairly plain language for the benefit of the committee members and the general public. After all, just a few days ago you showed you didn't even know what constitutes a double negative in English.

What I can do is compare the conflicting findings of these experts with the body of evidence as a whole to determine which is the most compelling opinion.

Again, no, no, no. You are acting like a teenager who just can't bring himself to admit he's wrong. There are no "conflicting findings" of experts when it comes to the N-wave evidence. For the umpteenth time, the NRC/NAS panel members and Linsker said nothing about the HSCA's acoustical experts' N-wave finding, much less dared to tackle the hard scientific evidence that those experts presented for the finding.

BTW, the NRC/NAS panel members and Linsker also ducked the powerful windshield-distortion correlations that the HSCA's acoustical experts documented, undoubtedly because those correlations, like the gunfire N-wave identification, were confirmed by a test firing. I quote from the HSCA's report:

Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone. On shot four, Weiss and Aschkenasy found no such distortion. (HSCA Report, pp. 74-75)

As HSCA deputy chief counsel Gary Cornwell noted,

The shock waves and windshield distortions were present on the shots where they should have been, and absent on the others. One more coincidence? Since the NRC described their findings as conclusive and not subject to question, one must wonder why the NRC ignored all of this evidence that corroborated the Barger and Weiss findings, but is totally inconsistent with the NRC findings that these impulses are not the actual sounds of gunfire. (Real Answers, 1998, pp. 113-114)

If there was a shooter on the GK, why did nobody see him (her?) before, during, or after the shooting. Why is there no physical evidence of a shot having been fired from the GK. Neither of the victims were hit by a frontal shot. No bullets or shells were recovered except for those positively matched to Oswald's rifle. Simply put, there is no other compelling evidence of a shot from the GK. In addition, by piecing together the photographic evidence, Myers proved that the motorcycle believed to have recorded the shooting through a stuck open microphone was not in the location the acoustics teams said he needed to be for their findings to be valid. All of this is why I believe the acoustics team simply misinterpreted the data.

Translation: You're again relying on your falsehoods and distortions about the evidence of a grassy knoll shooter to justify your refusal to accept the scientific acoustical evidence of a grassy knoll shooter.

Objective people who have read our exchanges in this forum are going to see that I have documented that the autopsy skull x-rays contain evidence of a right-frontal entry wound and the explosion of a frangible bullet just behind the frontal entry wound site, that several people (including one of the morticians) saw a small hole in the area of the right temple, that JFK's throat wound was an entry wound, that several witnesses smelled the acrid odor of gunpowder on/near the knoll right after the shooting, that several witnesses saw apparent gun smoke coming from the area of the fence on the knoll, that the Wiegman film shows a puff of smoke hanging in the air on the knoll, that 58 witnesses in the plaza said they heard gunfire from the knoll, that five police officers were told by witnesses right after the shooting that someone had been firing from the knoll, that seconds after the shots were fired both Chief Curry and Sheriff Decker ordered their men to see what had happened in the area behind the knoll, that at least two witnesses saw a man running from the knoll into the railyard right after the shooting, etc., etc., etc.

I did a search for conflicting opinions regarding what the acoustic evidence shows:

I'm sure you did. I guess it didn't occur to you to read the HSCA's acoustical reports and hearings themselves and to read the scholarly attacks and defenses of them, instead of relying on one of the dozens of Internet "fact check" sites.

I did a search for conflicting opinions regarding what the acoustic evidence shows:

"Scientists Who Disputed the BBN Findings on the Grassy Knoll Shot
The Bolt, Beranek and Newman (BBN) team, led by James E. Barger, analyzed the Dallas Police Department’s Dictabelt recording of Channel 1 during the Kennedy assassination. They found four impulse patterns that resembled gunshots, with a 50% probability that one came from the grassy knoll
Kennedy Assassination Home Page
Kennedy Assassination Home Page
+1
. This uncertainty led the House Select Committee on Assassinations (HSCA) to hire Mark R. Weiss and Ernest Aschkenasy to refine the analysis. Weiss and Aschkenasy concluded there was a 95% probability that the shot originated from the grassy knoll
Kennedy Assassination Home Page
Kennedy Assassination Home Page
+1.

However, the U.S. Justice Department, instead of further investigation, commissioned the National Research Council (NRC) of the National Academy of Sciences to review the evidence. The NRC panel (often referred to as the NAS Committee on Ballistic Acoustics) disputed the HSCA’s conclusions, claiming there was no scientific proof of a grassy knoll shot and that the acoustical evidence did not establish a high probability of a second gunman
jfk.hood.edu
jfk.hood.edu
+1.

The NRC’s findings were criticized by independent researchers such as W. Anthony Marsh, who argued the panel was biased, misapplied methods, and failed to conduct the necessary tests to refute the HSCA’s work
Archive
Archive. Marsh’s 1983 Rebuttal to Ramsey detailed errors in the NAS report and reaffirmed the accuracy of the HSCA’s acoustic analysis.

In summary:

BBN (Bolt, Beranek and Newman) – found 50% probability of grassy knoll shot.

Umm, nooo. As I've explained before, the BBN 50% probability finding was a preliminary finding that was made before the test firing was conducted in Dealey Plaza and before Weiss and Aschkenasy did their sonar analysis. Once BBN's scientists examined the sonar analysis of the 144.9 impulse pattern, they agreed the probability was 95% or higher.

You see, this is what happens when you go running to Internet "fact check" sites whose authors are not specialists in the field and who merely do their own Internet searches and then post links and summaries.

Weiss & Aschkenasy – found 95% probability of grassy knoll shot.

NRC/NAS Committee on Ballistic Acoustics – disputed the findings, claimed no proof of grassy knoll shot.

W. Anthony Marsh – independent critic of the NRC/NAS panel, argued their conclusions were invalid due to bias and methodological flaws "

I had to laugh when I saw one of the counter-dissenters was none other than Tony Marsh. That is almost as bad as having Michael T. Griffith providing evidence to support the cause of conspiracy.

Actually, Tony Marsh had no training in acoustics, whereas I received training in basic acoustics while in the Army and spent three years editing military manuals that dealt with acoustical direction-finding and signals-detection technology. That being said, Tony's critique of the NRC/NAS panel was solid.

MG: Again, even for you, this is a new height of silliness and self-discreditation. Linsker et al. didn't lay a finger on the N-wave evidence because they had no answer for it.

In your humble opinion.

Oh?! Well, then perhaps you would care to share why you think they said nothing about a major item of evidence that they knew the HSCA's acoustical scientists had cited as powerful scientific confirmation that the dictabelt contains gunfire?!

Again, dealing with you is like dealing with a spoiled teenager who can't admit he's wrong. We both know that if Linsker et al. had had even a remotely plausible explanation for the N-wave evidence, they would have gleefully presented it and would have gladly cited it as another reason to reject HSCA's acoustical findings.

MG: Umm, you realize that six of the 12 NRC/NAS panel members were physicists, right? You realize that four of them were engineers, not even electrical engineers but just regular engineers, right? You realize that one of them was a statistician, and that another one of them was a computer scientist, right? Right? In short, six physicists, four regular engineers, one statistician, and one computer scientist, and not one of them had ever worked or published in the field of acoustical science.

What they disputed was the scientific method used by BBN, something scientists in all fields should know something about.

This is just more of your juvenile back-pedaling. According to what you said, they were not qualified to dispute "the scientific method used by BBN" because they were not acoustical scientists and because the method was an acoustical science method. And, again, the BBN scientists used the same methods (not just one method) that they used to analyze the recording of the Kent State shooting to determine the location of the rifles that fired the shots.

For newcomers to this thread, I've already discussed the many errors, blunders, and omissions of the NRC/NAS panel:

https://www.jfkassassinationforum.com/index.php/topic,5215.msg186017.html#msg186017

Not really
No (bleep)! You should check a thesaurus. They are free online. You'd find out that disputed doesn't mean the same as refuted.  Mostly what you did is dispute and assume that you have refuted.

Umm, I didn't say "disputed." As for checking a thesaurus, humm, you're the same guy who just a few days ago proved he didn't know what a double negative is.

Anyway, I'll let readers decide whether or not I've refuted your arguments or merely "disputed" them, since you never admit when you're wrong, even when your blunder is self-evident.

MG: I think it is worth repeating that the NRC/NAS panel admitted (1) that they admitted they found a 93% probability that the timing-movement correlations identified by the BBN scientists occurred because the dictabelt recorded gunfire in Dealey Plaza during the assassination, and (2) that they admitted they found a 77.7% probability that the 144.9 impulse pattern was in fact gunfire from the grassy knoll. In your first reply in this thread, you cited an article by (of all people) Dale Myers that relies heavily on the NRC/NAS panel's report, yet neither you nor Myers nor any of the other amateur Internet hacks who attack the acoustical evidence has yet to address these two key admissions by the NRC/NAS panel.

So says our "amateur Internet hack".

Uh-huh. You can read the NRC/NAS report and see these facts for yourself.

The NRC/NAS report claims the BBN scientists erred in their calculation of the probability relating to the timing-movement correlations, that the BBN value of P<0.01 (i.e., less than 1%) was actually P=0.07 (i.e., 7%), and that therefore the “significance of the layout” indicated by Figure 22 in the BBN report was “considerably reduced” (Report of the Committee on Ballistic Acoustics, i.e., the NRC/NAS report, p. 37).

I trust that even you can comprehend that the panel's P=0.07 means the panel put the probability that chance caused the timing-movement correlations at 7% instead of BBN's calculation of less than 1% (P=0.07 vs. P<0.01). If you doubt that P=0.07 equals 7% and P<0.01 equals less than 1%, you can Google them.

Okay, so obviously, if the probability that chance caused the timing-movement correlations was 7%, then the probability that chance did not cause the correlations was 93%. You can do this much math, right?

Yes, a 7% probability of chance is more than a "less than 1%" probability of chance, but it is still an extremely low probability of chance.

As for the NRC/NAS panel's calculation of the probability that the 144.9 impulse pattern was caused by a grassy knot shot, after noting that Weiss and Aschkenasy calculated there was no more than a 5.3% probability (P=0.053) that the impulse pattern was not caused by gunfire, the panel argued that the probability was actually 22.3% (P=0.223) (Report of the Committee on Ballistic Acoustics, i.e., the NRC/NAS report, p. 40).

Alrighty, so if the probability that the 144.9 impulse pattern was not caused by grassy knoll gunfire was 22.3%, then the probability that the impulse pattern was caused by grassy knoll gunfire was 77.7%, right? You can do this much math, right?

Got it now?

I posted this article before but will do so again.

https://factually.co/fact-checks/justice/forensic-acoustic-studies-since-hsca-single-shooter-51b4c1

The final sentence pretty much sums up the veracity of the acoustics evidence:
"a minority of researchers continue to claim acoustic support for a grassy‑knoll shot but their conclusions remain disputed in peer and government reviews."

So, as noted, you're going to rely on some "fact check" site whose authors are not JFKA researchers and who merely did their own Internet search and copied and pasted links and wrote brief summaries.

"Peer and government reviews"? Not one of the critics who did those reviews was an acoustical scientist. I can excuse the "fact check" site authors for not knowing this, and for not knowing that it wasn't just Barger, Weiss, and Aschkenasy but also eight other acoustical scientists who worked on the HSCA's acoustical evidence, but you have no excuse and should have known better than to cite this superficial "fact check" article.

[John Corbett]

You seem to forget that we're talking about handguns in 1963. Anyway, regardless of the weapon, supersonic is supersonic. The HSCA's acoustical experts proved scientifically that the dictabelt contains N-waves caused by supersonic gunfire.

The NRC/NAS panel members knew this, and they knew they couldn't explain it away, so they just ignored it. Ditto for Linsker. If those guys had had even a remotely plausible alternative explanation for the precise N-wave characteristics in two of the dictabelt's impulse patterns, they would have said so. 

Of course you didn't, because the DPD radio system had an AGC circuit! This is just comically dumb. The HSCA's acoustical experts explained this to everyone's satisfaction way back in 1978. Even the two clueless dissenting HSCA congressmen who were determined to reject the acoustical evidence did not make this silly argument. And, needless to say, neither the NRC/NAS panel nor Linsker was foolish enough to make this idiotic argument either.

But, not surprisingly, here you are repeating it, even after I explained why the muzzle blasts and their echoes are not audible to the naked ear. 

No, no, no. You know this is false. Neither the NRC/NAS panel members nor Linsker disputed the presence of gunfire N-waves on the dictabelt. They didn't even so much as say "we don't believe there are gunfire N-waves on the dictabelt." They ducked the N-wave evidence entirely because they knew that if they disputed it, they would have to explain why. They simply ignored it, even though they knew the HSCA's acoustical scientists had justifiably cited it as powerful scientific evidence that dictabelt recorded gunfire.

You are not willing to be candid and credible on the N-wave evidence because you are pathologically determined to deny any evidence that refutes your theory of the shooting, even if the evidence is hard scientific evidence based on known principles and methods of acoustical science. 

I don't doubt that for a minute. I'm sure that Weiss and Aschkenasy's explanations flew right over your head, even though they were given in fairly plain language for the benefit of the committee members and the general public. After all, just a few days ago you showed you didn't even know what constitutes a double negative in English.

Again, no, no, no. You are acting like a teenager who just can't bring himself to admit he's wrong. There are no "conflicting findings" of experts when it comes to the N-wave evidence. For the umpteenth time, the NRC/NAS panel members and Linsker said nothing about the HSCA's acoustical experts' N-wave finding, much less dared to tackle the hard scientific evidence that those experts presented for the finding.

BTW, the NRC/NAS panel members and Linsker also ducked the powerful windshield-distortion correlations that the HSCA's acoustical experts documented, undoubtedly because those correlations, like the gunfire N-wave identification, were confirmed by a test firing. I quote from the HSCA's report:

Weiss and Aschkenasy also considered the distortion that a windshield might cause to the sound impulses received by a motorcycle microphone. They reasoned that the noise from the initial muzzle blast of a shot would be somewhat muted on the tape if it traveled through the windshield to the microphone. Test firings conducted under the auspices of the New York City Police Department confirmed this hypothesis. Further, an examination of the dispatch tape reflected similar distortions on shots one, two, and three, when the indicated positions of the motorcycle would have placed the windshield between the shooter and the microphone. On shot four, Weiss and Aschkenasy found no such distortion. (HSCA Report, pp. 74-75)

As HSCA deputy chief counsel Gary Cornwell noted,

The shock waves and windshield distortions were present on the shots where they should have been, and absent on the others. One more coincidence? Since the NRC described their findings as conclusive and not subject to question, one must wonder why the NRC ignored all of this evidence that corroborated the Barger and Weiss findings, but is totally inconsistent with the NRC findings that these impulses are not the actual sounds of gunfire. (Real Answers, 1998, pp. 113-114)

Translation: You're again relying on your falsehoods and distortions about the evidence of a grassy knoll shooter to justify your refusal to accept the scientific acoustical evidence of a grassy knoll shooter.

Objective people who have read our exchanges in this forum are going to see that I have documented that the autopsy skull x-rays contain evidence of a right-frontal entry wound and the explosion of a frangible bullet just behind the frontal entry wound site, that several people (including one of the morticians) saw a small hole in the area of the right temple, that JFK's throat wound was an entry wound, that several witnesses smelled the acrid odor of gunpowder on/near the knoll right after the shooting, that several witnesses saw apparent gun smoke coming from the area of the fence on the knoll, that the Wiegman film shows a puff of smoke hanging in the air on the knoll, that 58 witnesses in the plaza said they heard gunfire from the knoll, that five police officers were told by witnesses right after the shooting that someone had been firing from the knoll, that seconds after the shots were fired both Chief Curry and Sheriff Decker ordered their men to see what had happened in the area behind the knoll, that at least two witnesses saw a man running from the knoll into the railyard right after the shooting, etc., etc., etc.

I'm sure you did. I guess it didn't occur to you to read the HSCA's acoustical reports and hearings themselves and to read the scholarly attacks and defenses of them, instead of relying on one of the dozens of Internet "fact check" sites.

Umm, nooo. As I've explained before, the BBN 50% probability finding was a preliminary finding that was made before the test firing was conducted in Dealey Plaza and before Weiss and Aschkenasy did their sonar analysis. Once BBN's scientists examined the sonar analysis of the 144.9 impulse pattern, they agreed the probability was 95% or higher.

You see, this is what happens when you go running to Internet "fact check" sites whose authors are not specialists in the field and who merely do their own Internet searches and then post links and summaries.

Actually, Tony Marsh had no training in acoustics, whereas I received training in basic acoustics while in the Army and spent three years editing military manuals that dealt with acoustical direction-finding and signals-detection technology. That being said, Tony's critique of the NRC/NAS panel was solid.

Oh?! Well, then perhaps you would care to share why you think they said nothing about a major item of evidence that they knew the HSCA's acoustical scientists had cited as powerful scientific confirmation that the dictabelt contains gunfire?!

Again, dealing with you is like dealing with a spoiled teenager who can't admit he's wrong. We both know that if Linsker et al. had had even a remotely plausible explanation for the N-wave evidence, they would have gleefully presented it and would have gladly cited it as another reason to reject HSCA's acoustical findings.

This is just more of your juvenile back-pedaling. According to what you said, they were not qualified to dispute "the scientific method used by BBN" because they were not acoustical scientists and because the method was an acoustical science method. And, again, the BBN scientists used the same methods (not just one method) that they used to analyze the recording of the Kent State shooting to determine the location of the rifles that fired the shots.

For newcomers to this thread, I've already discussed the many errors, blunders, and omissions of the NRC/NAS panel:

https://www.jfkassassinationforum.com/index.php/topic,5215.msg186017.html#msg186017

Umm, I didn't say "disputed." As for checking a thesaurus, humm, you're the same guy who just a few days ago proved he didn't know what a double negative is.

I'm not going to spend an hour going over the same arguments point-by-point, but I couldn't let this one slide. I did not say you said disputed. I pointed out that you claimed to have refuted when all you did was dispute the findings of those who found fault with the BBN. I was responding to this statement by you:
"Repeating these lame arguments won't improve them. People who have read our previous exchanges in this forum will see that I have refuted every single one of these arguments".

You claimed to have refuted when all you had done was dispute their findings. That was the point I was making.

Anyway, I'll let readers decide whether or not I've refuted your arguments or merely "disputed" them, since you never admit when you're wrong, even when your blunder is self-evident.

Uh-huh. You can read the NRC/NAS report and see these facts for yourself.

The NRC/NAS report claims the BBN scientists erred in their calculation of the probability relating to the timing-movement correlations, that the BBN value of P<0.01 (i.e., less than 1%) was actually P=0.07 (i.e., 7%), and that therefore the “significance of the layout” indicated by Figure 22 in the BBN report was “considerably reduced” (Report of the Committee on Ballistic Acoustics, i.e., the NRC/NAS report, p. 37).

I trust that even you can comprehend that the panel's P=0.07 means the panel put the probability that chance caused the timing-movement correlations at 7% instead of BBN's calculation of less than 1% (P=0.07 vs. P<0.01). If you doubt that P=0.07 equals 7% and P<0.01 equals less than 1%, you can Google them.

Okay, so obviously, if the probability that chance caused the timing-movement correlations was 7%, then the probability that chance did not cause the correlations was 93%. You can do this much math, right?

Yes, a 7% probability of chance is more than a "less than 1%" probability of chance, but it is still an extremely low probability of chance.

As for the NRC/NAS panel's calculation of the probability that the 144.9 impulse pattern was caused by a grassy knot shot, after noting that Weiss and Aschkenasy calculated there was no more than a 5.3% probability (P=0.053) that the impulse pattern was not caused by gunfire, the panel argued that the probability was actually 22.3% (P=0.223) (Report of the Committee on Ballistic Acoustics, i.e., the NRC/NAS report, p. 40).

Alrighty, so if the probability that the 144.9 impulse pattern was not caused by grassy knoll gunfire was 22.3%, then the probability that the impulse pattern was caused by grassy knoll gunfire was 77.7%, right? You can do this much math, right?

Got it now?

So, as noted, you're going to rely on some "fact check" site whose authors are not JFKA researchers and who merely did their own Internet search and copied and pasted links and wrote brief summaries.

"Peer and government reviews"? Not one of the critics who did those reviews was an acoustical scientist. I can excuse the "fact check" site authors for not knowing this, and for not knowing that it wasn't just Barger, Weiss, and Aschkenasy but also eight other acoustical scientists who worked on the HSCA's acoustical evidence, but you have no excuse and should have known better than to cite this superficial "fact check" article.

I'm not going to go into the specifics of the acoustical evidence for the same reason I didn't try to do that with the medical evidence. Both these fields require years of study and experience to become experts in these fields. A layman such as myself is simply not qualified to render opinions on these subjects. That's why I choose to defer to people who are qualified. In the case of the acoustic evidence, there is a divided opinion among the scientific community as to whether or not the recording shows gunshots during the assassination or not. Those of us without acoustics training when faced with conflicting expert opinions have to decide which experts are the more credible, just like a jury must do when facing conflicting expert opinion at a trial. The reason I don't believe those who concluded the impulses on the recording were caused by gunshots is because that finding is inconsistent with the body of evidence as a whole. There is simply no other credible evidence that supports a shooter on the GK. No eyewitnesses even though one man had a perfect view of the area where the shot was alleged to have come from and other people rushed to that area immediately after the shooting without seeing a gunman. No shells or bullets were recovered other than those fired from Oswald's rifle. There is no medical evidence of either victim having been hit by a shot from in front of or to the side of them. The BBN finding depended on the recording having been of a stuck open microphone on a particular officer's motorcycle at a particular place. Dale Myers pieced together photographic evidence that the officer's motorcycle could not have been at the required location during the shooting. All of the above are valid reasons not to believe the BBN findings.

You claim to have had acoustics training although I don't know how your particular training applies to the evidence in question. However, you also have a distinct bias which makes your judgement of the acoustic evidence suspect. Tony Marsh had the same degree of bias as you do. When I was on Fred Litwin's podcast, I made the point that Tony had as good or better grasp of the facts of the JFKA as anyone I had come across in 35 years of arguing this case in various online forums. Tony's problem, which you share, is that he looked at all the evidence through the lens of conspiracy. He tried to make every piece of evidence conform to his belief that Oswald was not the lone assassin, just as you have been doing for 35 years. You will believe just about any conspiracy theory that comes along as long as it opposes the finding that Oswald acted alone. You don't even seem to care if these various theories are mutually exclusive or not. You try to interpret every piece of evidence to your faith-based belief there was a conspiracy.