The JFK Assassination Discussion & Debate > JFK Assassination Discussion & Debate
Acoustic Evidence
Michael T. Griffith:
One falsehood you hear from many critics of the acoustical evidence is that determining the origin and timing of gunfire from acoustical recordings was a new and untested science in 1978. In point of fact, one of the reasons the Acoustical Society of America recommended BBN to the HSCA was that BBN acoustical scientists had real-world experience in determining the origin and timing of gunfire from a sound recording in the 1970 Kent State shooting incident.
Dr. James Barger, BBN's chief acoustical scientist, was one of the BBN scientists involved with analyzing the audio recording of the Kent State shooting at the request of the prosecution. Dr. Barger and his team used a combination of waveform physics, sound-speed calculations, vector triangulation, and an onsite reenactment to identify the location and timing of the numerous shots that were fired. They identified the shock waves and muzzle blasts of the rifle fire. By measuring the precise time-delay intervals between the arrival of the shock waves and the arrival of the muzzle blasts, the BBN scientists were able to mathematically calculate which National Guardsmen were the first to fire shots.
The BBN team isolated each individual pair of sound impulses (shock plus blast) and plotted them chronologically to determine the exact tempo of the shooting, showing that the gunfire lasted for approximately 13 seconds. This allowed the BBN experts to determine that the shots were not fired in a single, simultaneous blast, but rather in a rapid, overlapping sequence. And, using vector triangulation and sound-speed calculations derived from the shock wave-muzzle blast intervals, Dr. Barger and his team were able to determine the gunfire's distance from the microphone and to establish that the gunfire came primarily from the crest of Blanket Hill, where the National Guardsman were positioned.
Does any of this sound familiar?
BTW, the BBN team's acoustical analysis in the Kent State case was so solid and impressive that it was not only admitted as evidence in the trial but was stipulated by the defense to be correct (5 HSCA 645). As most here know, defense lawyers don't like to stipulate to the correctness of damaging scientific evidence unless the evidence is beyond dispute.
Finally, I should point out that, not surprisingly, by 1978 Dr. Barger had already established himself as a recognized expert in applied acoustics, sound scattering, and sound reverberation, and had been a research fellow at Harvard University's Acoustics Research Laboratory before being hired by BBN. Before working at Harvard, he worked as a sonar scientist in the U.S. Navy's Underwater Sound Laboratory. By 1978, he had also had numerous papers published on acoustical science. After the HSCA investigation, Dr. Barger continued to have papers and articles published on acoustical science, including the following:
"Boomerang Mobile Counter Shooter Detection System" (2005, Proceedings of The International Society for Optical Engineering)
"Systems and Methods for Determining Shooter Locations with Weak Muzzle Detection" (2007, which earned a U.S. patent for BBN [by then Raytheon BBN]). "This technology of muzzle detection and system, applied in direction finders, acoustic wave reradiation, instruments, etc., solved the problems of inability to determine the range (distance) of the shooter, inaccurate derived distance information, and inability to determine the distance between the sensor(s) and the origin of the shockwave, so as to improve the disambiguation of the shooter's trajectory solution."
"System and Method for Identifying a Muzzle Blast Using a Multi-sensor Total Energy Approach" (2008, which earned a U.S. patent Raytheon BBN)
"System and Methods for Detecting Shooter Locations from an Aircraft" (2013, which earned a U.S. patent for Raytheon BBN)
John Corbett:
If the acoustic evidence is so solid, why didn't anybody see a gunman on the GK?
Michael T. Griffith:
--- Quote from: John Corbett on September 14, 2026, 02:55:33 PM ---If the acoustic evidence is so solid, why didn't anybody see a gunman on the GK?
--- End quote ---
Umm, because he fired from a concealed position behind the fence on the knoll.
Moreover, as I have pointed out to you before when you have argued against a grassy knoll shooter:
-- Several witnesses saw gun smoke coming from the area behind the fence on the knoll identified by the acoustical evidence as the location of the gunman.
-- We have hard photographic evidence that confirms the eyewitness accounts of seeing gun smoke on the knoll, i.e., the Wiegman film, which shows a small cloud of smoke hanging in the air near the fence on the knoll.
-- Several witnesses smelled the pungent odor of gunpowder on and near the knoll right after the shooting.
-- Two witnesses saw a man running from the grassy knoll into the railroad yard seconds after the shots were fired.
-- Dozens of witnesses in the plaza (at least 58) said they heard shots fired from the grassy knoll.
We still see lone-gunman theorists repeating the argument that those witnesses merely heard echoes of the sixth-floor gunman's alleged three shots. In his superb 1998 book Cover-Up, mathematician Stewart Galanor explains why the echoes argument is invalid:
Echoes are caused by sound bouncing off large, hard surfaces. . . . There are no buildings on the knoll or overpass that would have reflected sound back to confuse witnesses in Dealey Plaza. Beyond the knoll the terrain is flat with railroad tracks, while the knoll is covered with grass, shrubs, and trees that absorb sound. If there were any echoes, they would have been caused by the sound of rifle fire from the knoll echoing off the Book Depository (Cover-Up, p. 76).
-- Dozens of witnesses rushed up the grassy knoll right after the shooting because they believed shots came from there.
-- Seconds after the shooting, Sheriff Bill Decker ordered his officers to seal off the area of the railroad yard behind the knoll and the triple underpass: "Have Station 5 to move all men available out of my department, back into the railroad yards there in an effort to try to determine just what and where it happened down there, and hold everything secure until the homicide and other investigators can get there."
-- Seconds after the shooting, Chief Jesse Curry ordered his officers to check the area of the triple underpass: "Get a man on top of that triple underpass and see what happened up there!"
-- William Newman, a combat veteran, said he heard a shot come from behind him on the knoll and that he heard the whiz of the bullet as it passed near him. As someone who heard bullets whiz above him in the Army, I know exactly what Newman was describing.
-- Abraham Zapruder, before he knew what he was supposed to say, told the Secret Service on 11/22/63 that "the position of the assassin was behind Mr. Zapruder" (CD 87). Zapruder was standing on the pergola on the knoll, so the area behind him would have been very close to the spot identified by so many other witnesses and by the acoustical evidence.
John Corbett:
--- Quote from: Michael T. Griffith on September 14, 2026, 06:23:21 PM ---Umm, because he fired from a concealed position behind the fence on the knoll.
--- End quote ---
He wouldn't have been concealed from Lee Bowers who had a clear view of the area behind the fence from an elevated position. People raced to that area after the shooting including some from the overpass and no one saw a shooter. Because there wasn't one.
--- Quote ---
Moreover, as I have pointed out to you before when you have argued against a grassy knoll shooter:
-- Several witnesses saw gun smoke coming from the area behind the fence on the knoll identified by the acoustical evidence as the location of the gunman.
--- End quote ---
Witnesses said they saw smoke. Gun smoke was your addition. Had it been gun smoke, it would have dissipated almost immediately before anyone could have seen it, unless of course your shooter was firing a flintlock or a blunderbuss.
--- Quote ---
-- We have hard photographic evidence that confirms the eyewitness accounts of seeing gun smoke on the knoll, i.e., the Wiegman film, which shows a small cloud of smoke hanging in the air near the fence on the knoll.
--- End quote ---
Again, you are assuming it was gun smoke.
--- Quote ---
-- Several witnesses smelled the pungent odor of gunpowder on and near the knoll right after the shooting.
--- End quote ---
That gives no indication of the source of the shots because the residue from a gunshot can and does travel from where a gun was fired. Senator Yarborough was in a car on Elm St. when he smelled the residue and there are no reports of a shot fired from Elm St.
--- Quote ---
-- Two witnesses saw a man running from the grassy knoll into the railroad yard seconds after the shots were fired.
--- End quote ---
Which witnesses? Ed Hoffman? <chuckle>
--- Quote ---
-- Dozens of witnesses in the plaza (at least 58) said they heard shots fired from the grassy knoll.
--- End quote ---
Dozens of other witnesses heard those same shots and they said it sounded like they came from the TSBD. Those witnesses are corroborated by shells and a rifle found in the TSBD and eyewitnesses who SAW a gunman in the sniper's nest. No corroboration for the folks who thought the shots came from the GK.
--- Quote ---
We still see lone-gunman theorists repeating the argument that those witnesses merely heard echoes of the sixth-floor gunman's alleged three shots. In his superb 1998 book Cover-Up, mathematician Stewart Galanor explains why the echoes argument is invalid:
Echoes are caused by sound bouncing off large, hard surfaces. . . . There are no buildings on the knoll or overpass that would have reflected sound back to confuse witnesses in Dealey Plaza. Beyond the knoll the terrain is flat with railroad tracks, while the knoll is covered with grass, shrubs, and trees that absorb sound. If there were any echoes, they would have been caused by the sound of rifle fire from the knoll echoing off the Book Depository (Cover-Up, p. 76).
--- End quote ---
I don't know what led those people to believe shots sounded like they came from the GK but I do know there is no physical evidence of a shooter there nor eyewitnesses. I also know from first hand experience it can be difficult to locate the source of the gunfire based on sound. I live in a rural area and gunfire is not an uncommon sound, especially right before the deer gun season. When I'm walking my dogs, I hear the gunfire but I don't know where it is coming from until I visually sight which of my neighbors is taking target practice. Sometimes it turns out the shots were 90 degrees or more away from where it sounded like the shots came from, and I don't have tall buildings around to create the echos.
--- Quote ---
-- Dozens of witnesses rushed up the grassy knoll right after the shooting because they believed shots came from there.
--- End quote ---
WOW! All those people rushed the GK and not one of them saw a gunman. What are the odds?
--- Quote ---
-- Seconds after the shooting, Sheriff Bill Decker ordered his officers to seal off the area of the railroad yard behind the knoll and the triple underpass: "Have Station 5 to move all men available out of my department, back into the railroad yards there in an effort to try to determine just what and where it happened down there, and hold everything secure until the homicide and other investigators can get there."
-- Seconds after the shooting, Chief Jesse Curry ordered his officers to check the area of the triple underpass: "Get a man on top of that triple underpass and see what happened up there!"
--- End quote ---
Which simply indicates pinning a badge on your shirt doesn't give one special powers of auditory perception. They can be fooled just as easily as anybody else. It's notable that Decker and Curry directed their resources to different places.
--- Quote ---
-- William Newman, a combat veteran, said he heard a shot come from behind him on the knoll and that he heard the whiz of the bullet as it passed near him. As someone who heard bullets whiz above him in the Army, I know exactly what Newman was describing.
-- Abraham Zapruder, before he knew what he was supposed to say, told the Secret Service on 11/22/63 that "the position of the assassin was behind Mr. Zapruder" (CD 87). Zapruder was standing on the pergola on the knoll, so the area behind him would have been very close to the spot identified by so many other witnesses and by the acoustical evidence.
--- End quote ---
Looks like Newman and Zapruder didn't have any special powers of auditory perception either.
Michael T. Griffith:
--- Quote from: Michael T. Griffith on September 14, 2026, 06:23:21 PM ---Umm, because he fired from a concealed position behind the fence on the knoll.
Moreover, as I have pointed out to you before when you have argued against a grassy knoll shooter:
-- Several witnesses saw gun smoke coming from the area behind the fence on the knoll identified by the acoustical evidence as the location of the gunman.
-- We have hard photographic evidence that confirms the eyewitness accounts of seeing gun smoke on the knoll, i.e., the Wiegman film, which shows a small cloud of smoke hanging in the air near the fence on the knoll.
-- Several witnesses smelled the pungent odor of gunpowder on and near the knoll right after the shooting.
-- Two witnesses saw a man running from the grassy knoll into the railroad yard seconds after the shots were fired.
-- Dozens of witnesses in the plaza (at least 58) said they heard shots fired from the grassy knoll.
We still see lone-gunman theorists repeating the argument that those witnesses merely heard echoes of the sixth-floor gunman's alleged three shots. In his superb 1998 book Cover-Up, mathematician Stewart Galanor explains why the echoes argument is invalid:
Echoes are caused by sound bouncing off large, hard surfaces. . . . There are no buildings on the knoll or overpass that would have reflected sound back to confuse witnesses in Dealey Plaza. Beyond the knoll the terrain is flat with railroad tracks, while the knoll is covered with grass, shrubs, and trees that absorb sound. If there were any echoes, they would have been caused by the sound of rifle fire from the knoll echoing off the Book Depository (Cover-Up, p. 76).
-- Dozens of witnesses rushed up the grassy knoll right after the shooting because they believed shots came from there.
-- Seconds after the shooting, Sheriff Bill Decker ordered his officers to seal off the area of the railroad yard behind the knoll and the triple underpass: "Have Station 5 to move all men available out of my department, back into the railroad yards there in an effort to try to determine just what and where it happened down there, and hold everything secure until the homicide and other investigators can get there."
-- Seconds after the shooting, Chief Jesse Curry ordered his officers to check the area of the triple underpass: "Get a man on top of that triple underpass and see what happened up there!"
-- William Newman, a combat veteran, said he heard a shot come from behind him on the knoll and that he heard the whiz of the bullet as it passed near him. As someone who heard bullets whiz above him in the Army, I know exactly what Newman was describing.
-- Abraham Zapruder, before he knew what he was supposed to say, told the Secret Service on 11/22/63 that "the position of the assassin was behind Mr. Zapruder" (CD 87). Zapruder was standing on the pergola on the knoll, so the area behind him would have been very close to the spot identified by so many other witnesses and by the acoustical evidence.
--- End quote ---
To follow up on these evidences, I should mention the fact that Lee Bowers saw three cars separately recon the parking lot behind the knoll during the 25 minutes leading up to the assassination. This "probing" caught Bowers' attention because the area had been sealed off and there had been no movement in the area since around 11:00. Bowers said the driver of the second car seemed to be speaking into a microphone. The HSCA rightly cited Bowers' account as evidence of conspiracy. The following video includes segments of an interview with Bowers in which he discusses the three suspicious cars:
The Suspicious Death of Lee Bowers
I am agnostic about the circumstances of Bowers' death, but it is worth noting that Bowers reportedly told friends that he feared for his life. Anyway, most of the video deals with Bowers' account of the three cars' recon of the parking lot behind the knoll.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---Quote from: Michael T. Griffith on Yesterday at 06:23:21 PM
Umm, because he fired from a concealed position behind the fence on the knoll.
He wouldn't have been concealed from Lee Bowers who had a clear view of the area behind the fence from an elevated position.
--- End quote ---
Can you ever deal with evidence in an honest, credible way? We've had this very discussion before, yet you just keep repeating your argument and ignoring the counter-arguments.
So, again, as I've explained to you before, Bowers was not watching the two men he saw walk to a point behind the fence after he saw them go there, but later, during the shooting, he said his attention was drawn to that spot because he saw a "flash of light" or "smoke" from that location and this this caused him to think something unusual was going on there.
Surely you're aware of Bowers' account, but you ignore it and falsely imply that Bowers didn't see anything suspicious behind the fence during the shooting.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---People raced to that area after the shooting including some from the overpass and no one saw a shooter. Because there wasn't one.
--- End quote ---
Oh my goodness. What about the witnesses, including a policeman, who said men flashing SS badges prevented them from going farther into the parking lot? Or have you never read about these witnesses? Surely you have. Yet, again, you just brush aside contrary evidence and make misleading arguments based on your deceptive omission.
Furthermore, although dozens of people ran toward and up the knoll after the shooting, they did not do so immediately after the last shot, so the gunman and his accomplice had time to run into the parking lot.
Bowers indicated that his attention was -- naturally -- drawn to the pandemonium that broke out in Dealey Plaza after the shooting, which would explain why he would not have noticed one or two men running into the parking lot. J.C. Price saw a man who was running into the parking lot after the shooting because Price was watching events from the roof of the Terminal Annex Building. And Price was not the only one who saw a man running from the fence area into the railyard after the shooting.
Of course you wave aside Ed Hoffman's account of seeing two men, one with a rifle, behind the fence on the knoll, but his story is credible.
I would direct interested readers to Mark Arnold's article "Eyewitness to Tragedy: The Ed Hoffman Story" Arnold shows that Hoffman's account has been subject to deliberate misrepresentation and faulty sign-language interpretation. Arnold looks at Hoffman's story in detail and concludes,
The one constant in the whole Ed Hoffman narrative is that if one takes the time and care necessary to understand him, his story has never changed: that on Friday, November 22, 1963, he was standing on Stemmons Freeway with an excellent view east, into the area behind the picket fence atop the grassy knoll, and there saw two men work together, one of them shooting at the President with a rifle, the other breaking it down and making his getaway through the railyard.
I would also direct interested readers to Casey Quinlan and Brian K. Edwards' book Beyond the Fence Line: The Eyewitness Account of Ed Hoffman and the Murder of President John F. Kennedy. Quinlan and Edwards refute every objection that critics have raised against Hoffman's account.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---Witnesses said they saw smoke. Gun smoke was your addition.
--- End quote ---
Uh, they thought it was gun smoke.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---Quote from: Michael T. Griffith on Yesterday at 06:23:21 PM
-- We have hard photographic evidence that confirms the eyewitness accounts of seeing gun smoke on the knoll, i.e., the Wiegman film, which shows a small cloud of smoke hanging in the air near the fence on the knoll.
Had it been gun smoke, it would have dissipated almost immediately before anyone could have seen it, unless of course your shooter was firing a flintlock or a blunderbuss.
--- End quote ---
Utter nonsense. This myth was answered was decades ago, but of course you're decades behind the information curve. For starters, take a look at the footage of the 1966 Charles Whitman shooting: you can see obvious clouds of gun smoke hang in the air from his rifle firings, and they obviously do not dissipate "almost immediately." Innumerable wartime and other shooting photos and footage show that gun smoke can hang in the air for 5-10 minutes.
Furthermore, your side only has two explanations for the smoke in the Wiegman frame, and both of them are untenable. Your side says the smoke is either motorcycle exhaust or smoke from the steam pipe in the railroad yard. The patrol bikes weren't emitting any smoke, and the steam pipe was over 100 feet from the area where six witnesses said they saw gun smoke.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---I don't know what led those people to believe shots sounded like they came from the GK. . . .
--- End quote ---
LOL! Here's what led them: they heard gunshots coming from the grassy knoll!
Let's start with the scientifically established fact that there was a gunman firing from behind the fence on the grassy knoll. The gunman's location was determined by a refined sonar analysis done by Queens College acoustical scientists Mark Weiss and Ernest Aschkenasy. They found that all 26 of the echo patterns of the grassy knoll test shot matched the 26 echo patterns of the dictabelt’s 144.9 impulse pattern (8 HSCA 27-29). The scientists conservatively calculated the probability of the grassy knoll shot as 95% or higher, i.e., at least 95%. In statistics, that is a virtual certainty; moreover, it was later shown that the 95+% probability figure was too conservative, that the actual probability is virtually 100%.
Even after introducing two outright errors in their calculations, the NRC/NAS panel could only reduce the grassy knoll shot's probability to 77.7%.
Dozens of witnesses heard the grassy knoll gunman firing; six of them saw gun smoke from his rifle; and the Wiegman film captured some of that smoke. One of the gunman's bullets came so close to combat veteran Bill Newman that he could hear the bullet whiz by him. Go talk to any veteran who has experienced rifle bullets coming close enough that he could hear the bullets whiz by him.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---Which simply indicates pinning a badge on your shirt doesn't give one special powers of auditory perception. They can be fooled just as easily as anybody else.
--- End quote ---
LOL! Yeah, you bet. Never mind that Curry and Decker were both riding in the lead car and were perfectly positioned to hear gunfire from the knoll, which was right next to the triple underpass and right in front of the railroad yard. Yeah, just never mind that.
And never mind that they both ordered their men to secure and search the triple underpass-railyard area. Yeah, just a "coincidence," right?
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---It's notable that Decker and Curry directed their resources to different places.
--- End quote ---
You surely know this is misleading. Decker ordered his officers to seal off the area of the railroad yard behind the knoll and the triple underpass. Curry ordered his officers to check the area of the triple underpass and said to get a man on top of the underpass to see what happened there. Anyone who looks at a map of Dealey Plaza and understands English can see that Decker and Curry sent their men to essentially the same area.
--- Quote from: John Corbett on September 14, 2026, 06:51:09 PM ---Looks like Newman and Zapruder didn't have any special powers of auditory perception either.
--- End quote ---
Uh-huh. Of course. I'm sure Newman, a combat veteran, just dreamed he heard a bullet whiz by him from behind. Again, go talk to any veteran who has experienced hearing bullets whiz by him.
And never mind that Zapruder initially categorically stated that the gunman was behind him, and that there was strong "reverberation" all around him, right? He was standing nearly 250 feet from the sixth-floor window, nearly a football field away. Only gunfire that was fired near Zapruder could have caused physically discernible reverberation on the pergola on which he was standing.
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