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."