The "hold everything secure" was crosstalk from a channel 2 radio nearby the stuck motorcycle microphone on channel 1. So any other example would have to meet the same narrow condition.
So, of all the sounds or “sound impulses”, which were recorded “out of order”, the lone example, according to Dr. Thomas, is the “sound impulses” from the gunshots themselves.
What a fantastic coincidence.
In other words, the hypothesis that the Dictabelt recording contains sounds which are out of order, is totally without support. If this hypothesis had any support, we would have other examples, like maybe:
Statement C - Officer X – “Officer X here. I have reached Main and Texas.”
. . .
Statement A – Dispatcher – “Officer X, proceed immediately to Main and Texas.”
Statement B – Officer X – “I am on my way. I am almost there.”
Clearly, if we had such an example, we would have statements that were recorded out of order, since the real order in time was Statement A, B, C.
The HSCA/Dr. Thomas acoustic hypothesis, is ultimately based on a probability argument. The type of argument you criticize so much when I use it.
I have no idea what you're talking about. Main and Texas? Who said that the impulses were recorded "out of order"? The impulses and the "hold everything secure" announcement were on two different recording devices with different speeds and two different dispatchers with unsynchronized clocks.
I've never opined on any "probability argument" made by Thomas.
And yet the “four alleged gunshots” are the only “sounds” that were recorded out of order. No other examples can be named.
Why not? Do you deny that the 1978 Accoustic/Dr. Thomas arguments are probability arguments?
The supporters of the HSCA 1978 Acoustic study and of Dr. Thomas Acoustic study, admit that the 4 N-waves, the alleged “4 gunshots” are found on the recording near the phrase “Hold everything secure”. This would indicate that the alleged “4 gunshots” were recorded a minute, or perhaps a half minute, too late to have been the real gunshots. The claim is that somehow these “sounds” were offset from their true position in time.
Michael Griffith and John Iacoletti have tried to change the subject of this thread. For those who may have forgotten, this thread is about the following question:
On the Dictabelt recording, there are 4 N-waves (I have read there are a good deal more than that scattered over the recording, but they focused on these 4) which, though they don’t sound anything like a gunshot, are actual gunshots.
The supporters of the HSCA 1978 Acoustic study and of Dr. Thomas Acoustic study, admit that the 4 N-waves, the alleged “4 gunshots” are found on the recording near the phrase “Hold everything secure”. This would indicate that the alleged “4 gunshots” were recorded a minute, or perhaps a half minute, too late to have been the real gunshots. The claim is that somehow these “sounds” were offset from their true position in time.
Question:
Can anyone come up with another example of a sound, or a spoken phrase, anything, that got offset by 30 or more seconds?
They have not answered this one basic question, but instead go off on all kinds of tangents. Clearly, the answer is no, they can’t. So, it appears everything else appears in the proper order, all the spoken phrases, everything, was recorded in the proper order. Everything except the alleged 4 gunshots.
So, when they speak of the odds that the 1963 N-waves match so closely to the 1978 N-waves, to a chance, which they have at times said was 1 in 2, or 1 in 20, or 1 in 25, consider all the hundreds of spoken phrases, and all the other sounds, and the only sound that got offset in time, was the “4 gunshots”.
And as an aside, I might point out, let’s assume, for the moment, that they are right. The 4 sound impulses were displayed in time from where they actually occurred, we don’t know if they actually occurred right when they are supposed to have occurred. For all anyone knows, if they didn’t happen 1 minute too late, maybe they really happened 2 minutes too late, or maybe 1 minute too early. There is nothing to show that the cause of these 4 N-waves happened within the period of, let’s say, z133 through z400. Nothing.
The 1978 HSCA Acoustic study that claims four shots were fired rests on 4 “N-waves” found on the recording, that don’t sound like gunshots, that don’t sound like anything, are actually gunshots. The difficulty, is that they occur about the same time Sheriff Decker is heard to say “Hold everything secure . . .”, which, on the surface, would indicate that these alleged 4 shots occurred about 90 seconds too late to have been the shots.
The claim is, that this doesn’t matter because sometimes sounds got recorded in the wrong order. This is a totally unsupported claim. It would have support if we had something like the following recording:
[SNIP]. . . .
A laymen’s objection to the 1978 Acoustic study.
1. The “gunshots” don’t sound like gunshots. Indeed, they don’t sound like anything. They are inaudible.
The breezy explanation is that the Dictabelt was designed to record voices, not gunshots. That doesn’t seem right to me. I never heard of a device designed to record voices not also being able to record loud gunshots. [SNIP]. . . .
2. The hypothesis that the Dictabelt would sometimes record sounds out of order in time, is something I would need to see an example of. It doesn’t sound likely to me.
I think I should also mention a glaring error in the 1978 Acoustic study. In 1978, the Dictabelt recorder was still used to keep a record of the police radio. So why didn’t they have the Dictabelt be used to record the sounds of their test firings of rifles at Dealey Plaza that day? This could have been easily done. [SNIP]. . . .
Had they taken this elementary step; we would know:
1. Does the Dictabelt record gunshots as audible sounds, that sound like gunshots, or at least audible sounds? Or as inaudible N-waves?
2. Are events recorded out of temporal order? If so, how often does this occur? If it does, is this associated with crosstalk?
Because the 1978 Acoustic Experts did not take this elementary step, we don’t know. And, I believe the Dictabelt technology no longer exists and so unlike 1978, we can not test this, not in Dealey Plaza, or anywhere else.
This is an elemental error. At the end of the day, it doesn’t matter what their instruments recorded. It is what a Dictabelt records. That is what should have been studied. [SNIP]. . . .
You are making an assumption that there was a source of a bell in Dealey Plaza, but that is your assumption. However, you have to look at the tape and the data on the tape a little more carefully, and one can see there an indication of a keying-on-transient which means that someone else tried to get onto the channel at that very time. He may have been in position to be close to a source of a carillon bell rather than anyone in Dealey Plaza, because there is associated with that carillon bell some indication of somebody else transmitting at the same time, which puts it just equally as well outside of Dealey Plaza. . . .
In fact, if you listen to the police tape recording during the entire period of the 5 minutes when the microphone on this motorcycle was accidentally on, you can in fact hear other transmitters coming on. Most of them failed insofar as all you hear is the microphone click and you hear a kind of a chirp as they try to capture the channel.
But there are a number of times where you do hear other voices coming on, other people communicating, sometimes very distorted sounds of the voices, sometimes quite clear and intelligible; and it is all during the time that this one transmitter has been on. In fact, as you go on in time past the point at which the shots occur, the ability of other transmitters to come into the channel becomes increasingly--it occurs more frequently. You hear more people coming in. You hear comments to the effect that somebody has his microphone button stuck, and it is all audible and understandable, so there are indeed several transmitters being received simultaneously during that period, and therefore it could very well have been that there was another motorcycle who happened to key on at just that point in time and picked up the sound of a bell somewhere. (5 HSCA 591-592)
* The BBN scientists did notice the presence of voices on the dictabelt, some clear and some faint, but they did not analyze them because they focused on the gunshot impulses and the N-waves on the dictabelt.
* The BBN scientists noted that the loudest sound impulses from gunfire are much louder than the loudness of the sound for which the radio was designed to operate, namely, human speech. These loud impulses overdrive the radio circuitry. Because of the radio transmitter’s restricting circuits, very loud sounds are recorded in distorted fashion and appear as much weaker signals than they really are.
The 1978 HSCA Acoustic study that claims four shots were fired rests on 4 “N-waves” found on the recording, that don’t sound like gunshots, that don’t sound like anything, are actually gunshots.
Quote from: Michael T. Griffith on September 11, 2020, 07:56:41 PM
* The BBN scientists did notice the presence of voices on the dictabelt, some clear and some faint, but they did not analyze them because they focused on the gunshot impulses and the N-waves on the dictabelt.
An incredible oversight.
It was of fundamental importance to determine of these 4 inaudible N-waves occur at the correct time to be the gunshots. Why wouldn’t they focus on the voices to determine this? How else could it be determined if the 4 inaudible N-waves occurred at the correct time or not?
Well, the principles are basically the fundamental principles in acoustics, namely, that if someone makes a loud noise somewhere, like here [witness claps his hands], that sort of thing, everybody in this room can hear that noise, which means that sound moves out in all possible directions. A second principle is that that sound which they hear directly also will bounce off walls and be reflected. So they will hear not only the direct sound but also sounds called echoes bouncing from walls, corners, and other surfaces. The third principle, also very fundamental, is that the speed of sound is constant in whatever direction it may go. So that the farther you are from the source of the sound, the longer it will take for that sound to reach you, whether that source is, in fact, the original source of the sound or a reflecting surface which would cause an echo. I would like to illustrate basically what is meant by echoes at this point here. I think everybody is pretty much aware of what happens if you stand at a canyon and holler something like "Hello" and you get back a series of "Hello, hello, hello," that sort of thing. You can hear each of these echoes in such a circumstance because the reflecting surfaces are quite far apart from you and from each other. In a situation such as an echo generated in Dealey Plaza, you have reflecting surfaces, also the walls and corners of the buildings there. They, too, will generate echoes, but they will tend to come in very much more closely in sequence so that even if you have a very short, sharp sound such as a rifle firing, OK, or again a clap of the hands, you will get back what to an observer or many observers will sound like a single, loud bang type thing. . . .
As I indicated, each position in the plaza would have a unique set of echoes associated with it. If a sound heard on the police tape was, in fact, the sound of gunfire heard by a microphone-and a microphone, remember, is kind of an electronic ear--it hears the same as an ear will hear. If that indeed was the case, then I ought to be able to find a position for that microphone and a position for the gun such that I could predict a pattern of echoes that would match the sounds heard on the police tape to a high degree of accuracy. I could then say that this kind of match of a predicted pattern with the observed pattern is so close that the probability that what I am really looking at on the Dallas police tape is noise becomes very small. So we set out to be able to predict what the echo structures would be at various locations in Dealey Plaza. This was the whole art of it.
As I say, it was done by using the simple concept that sound would travel in all directions from a source and that it will reflect off surfaces and travel back. . . .
In fact, this brings up another point. If, in fact, after diligent searching we could not get a pattern of echoes, a predicted pattern of echoes, that would sufficiently closely match the impulses visible on the police tape recording, then we would have to conclude either that we did not have a shot recorded there, or that if we did have a shot recorded, then the motorcycle was not anywhere near the position we had assumed it to be, or the shooter was not anywhere near the position we assumed to be, or both conditions. . . .
So we started moving the microphone down the street at 11 miles an hour, and for this set of moved positions-now predicting what the echo pattern would be at every position as it comes on down, let's say, at what time it would receive each of these echoes.
This is a somewhat more complicated process. It is the same process; it just takes a lot longer because you have to do a lot more calculations.
As soon as we started doing that, it became immediately obvious we could quite easily find positions for the rifle and for the motorcycle, such that the match at both the early and the late echoes was getting increasingly close; and, in fact, once we were there, we were practically in the ballpark. It was a little more work, and we closed on a set of echoes that we could predict that matched the observed impulses on this pattern with an accuracy of approximately one-thousandth of a second. . . .
Mr. CORNWELL. Are you able to quantify in some fashion the probability that results from the ability to identify a large number of peaks, as you did, to that degree of precision?
Mr. WEISS. Yes, if you have a fit of some 22 points, you have a terrific fit to begin with. It really is hard to imagine this could be an accident, but you can't express it in those terms. You have to reduce it to some formal number that you can actually show is reasonable.
Now some of these echoes, and particularly the early ones coming from surfaces such as doorways over here and some corners over here, come in small. In fact, they come in below the noise level of impulse peaks in the general area of the recording where this is heard.
There is noise that is heard; there is the motorcycle noises; there is electrical noise; static is coming in. All of this is approximately at the level shown by these dashed lines on this exhibit. . . .
Now if the muzzle blast came in looking something like this, 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, the sound could equally, with equal probability, start out going this way and come back this way. 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. . . .
Well, the effect of that can be predicted. But to confirm our understanding of this, we arranged with the New York City Police Department to perform some experiments at their shooting range in the Bronx . We went out there, and they trotted out an old Harley-Davidson motorcycle and put a transmitter on it, vintage 1963 or 1964, and an old microphone pretty much the same kind as was used by the Dallas Police Department, and we performed some experiments with people firing rifles at various locations, sometimes with the motorcycle facing the shooter, sometimes with the motorcycle crosswise to the shooter. At the same time we made recordings using high fidelity equipment of the sounds of the shots.
Now there were two kinds of recordings made. The first, as I say, was high fidelity equipment, good microphone, good recorder on the spot. The second was through the microphone which was on the motorbike, which was a microphone of the type used in Dallas, through the transmitter, and recorded downtown at the police communications laboratory. And we compared the results of these two recordings, and what we found was exactly what we had thought we would find, that is, that in the case of the high fidelity recording, we got that kind of big, first spike upward and downward, and so on . In the case of the recording made through the police microphone, that first spike was greatly attenuated and it went negative and came back up and so on. This was true, however, only in the case where the motorcycle was facing the rifle.
When the motorcycle was crosswise to the rifle, the recording made by the police microphone fairly closely matched, looks, looked pretty much like, with some distortions, but looked pretty much like the recording made using the high fidelity equipment.
So it was essentially confirmed that the windshield really does have this effect on reducing the strength of that initial, very sharp spike received, and, of course, this is what we have over here. It is consistent with the assumption that this is a microphone behind the windshield facing a rifle. . . .
Chairman STOKES. Let me ask you this . This is 1978, this tape existed in 1963. Had this tape been given, let's say, to you or other scientists who specialized in this particular area, have you done anything new that could not have been done in 1963 with this tape?
Mr. WEISS. No, sir; the only thing that is new-this is an old technology that we are dealing with-the application is new, insofar as the use of the physics and science of acoustics for predicting the position of a microphone and/or a gun. I believe that the first application of it was only several years ago, and by Dr. Barger, in the case of the Kent State shootings. But other than that, there is nothing new in this at all. . . .
In the case of shot No. 3, since there is evidence of a shockwave preceding the muzzle blast, then it would have to be concluded that this was not a backfire, since backfires are not known to produce shockwave sounds.
We had no preconception as to what we were going to find. If anything, when we first heard the tape recording and first began to examine the data, our initial reaction was, somebody has got to be kidding; this can't be gunshots . But as we examined the data more carefully, subjected it to all the tests that we have described, the procedures that we have described, the results of the analyses themselves convinced us of where we were heading.
We can say that the bullet [of the grassy knoll shot] was not fired straight up in the air because had it been, you would not have received a shockwave impulse at that microphone position; and, indeed, if it had been fired in a direction reverse to that of the limousine, you also would not have received a shockwave impulse.
Mr. FITHIAN . Well, then, let me ask it another way. You were concerned about the alteration of the nature of the impulse by the windshield of the motorcycle?
Mr. WEISS. That is correct, only insofar as it is another means of observing a consistency between what is seen in the pattern and what is expected to be seen based upon both theory and experiment, that is, that the leading edge is much smaller than the cycle that immediately follows it. In reality, when a muzzle blast occurs, that leading edge is very much larger than the cycle that will follow it . There are two things that are reducing it as we observe it here. The first is the effect of the windshield, and the second is the effect of the compression caused by limiting action in the microphone and transmitter and almost certainly in the receiver and recorder as well.
Mr. FITHIAN. Does that in any way call into question the identification of the sound, itself, as that which reflects a gunshot from a rifle?
Mr. WEISS. Not seriously. Well, in effect, actually, rather than contradicting it, in a sense it supports it because all we see is all explainable and consistent with what we should expect to see if we take into account all the factors of the situation. (5 HSCA 557-560, 569, 581-582, 584, 588, 593, 597, 605)
It appears they never actually verified, in a controlled environment, that gunshots would record on a dicta-belt machine in any way recognizable. Correct?
Well, the effect of that can be predicted. But to confirm our understanding of this, we arranged with the New York City Police Department to perform some experiments at their shooting range in the Bronx. We went out there, and they trotted out an old Harley-Davidson motorcycle and put a transmitter on it, vintage 1963 or 1964, and an old microphone pretty much the same kind as was used by the Dallas Police Department, and we performed some experiments with people firing rifles at various locations, sometimes with the motorcycle facing the shooter, sometimes with the motorcycle crosswise to the shooter. At the same time we made recordings using high fidelity equipment of the sounds of the shots.
Now there were two kinds of recordings made. The first, as I say, was high fidelity equipment, good microphone, good recorder on the spot. The second was through the microphone which was on the motorbike, which was a microphone of the type used in Dallas, through the transmitter, and recorded downtown at the police communications laboratory. And we compared the results of these two recordings, and what we found was exactly what we had thought we would find, that is, that in the case of the high fidelity recording, we got that kind of big, first spike upward and downward, and so on . In the case of the recording made through the police microphone, that first spike was greatly attenuated and it went negative and came back up and so on. This was true, however, only in the case where the motorcycle was facing the rifle.
When the motorcycle was crosswise to the rifle, the recording made by the police microphone fairly closely matched, looks, looked pretty much like, with some distortions, but looked pretty much like the recording made using the high fidelity equipment.
So it was essentially confirmed that the windshield really does have this effect on reducing the strength of that initial, very sharp spike received, and, of course, this is what we have over here. It is consistent with the assumption that this is a microphone behind the windshield facing a rifle. . . .
During 1963, communications that were transmitted on channel 1 of the DPD radio dispatching system were recorded continuously on a Dictabelt recorder. On November 22,1963, a microphone on a mobile transmitter that was set to channel 1 apparently became stuck in the “on” position at about 12:28 p.m. and for about 5 minutes continuously transmitted sounds that it picked up.
When we first listened to this interval on the DPD recording, we found that it contained a nearly continuous noise, with occasional speech, whistles, and clicks. Also recorded on the Dictabelt in this interval were the sounds that BBN identified as probable gunshots. To the ear, these sounds resembled static much more than they did a gunshot. However, as Dr. Barger testified in September, and as we independently verified, the equipment that was used in the DPD radio dispatching system was not designed to handle sounds as intense as a gunshot, and it was therefore likely to have recorded such sounds with very poor fidelity.
Consequently, we recognized that these static-like sounds could be distorted gunshot sounds. On the other hand, such static-like sounds, theoretically could have been generated by a number of other sources, some acoustic, some related to electrical or mechanical disturbances in the DPD radio transmission, reception or recording equipment. Some test more discerning than the human ear was required to determine the probable cause of the sound impulses.
To answer the basic question, "Was the third group of recorded sounds generated by a gunshot from the grassy knoll?" with a high level of certainty, these sounds needed to be examined for some characteristic that they would have had if they had been generated by such a gunshot, and would not be likely to have had if they had not been. Of the several characteristics that can be used, the most effective and most reliable one is the sequence of delay times of the muzzle-blast echoes.
The firing of a gun generates a very loud, very brief explosive blast at the muzzle of the gun. This sound, which typically lasts about five one-thousandths of a second (0.005 seconds, or 5 milliseconds), spreads out in all directions from the gun. . . .
The time taken for the muzzle blast to be heard at some location depends solely on how fast the sound travels and how far the listener is from the gun. For example, at 65°F the speed of sound is 1123 ft/sec. A listener 112.3 feet away from a gun would hear its muzzle blast 0.1 second after the gun was fired. The time taken for the muzzle blast echoes to be heard also depends on the speed of sound and on the total distance each echo must travel, which is the total of the distance from the gun to the echo-producing object and then to the listener. Since the distance traveled by the muzzle blast to a listener must be less than the distance traveled by one of its echoes, the bang of the muzzle blast is always heard first. Then the echoes that are produced by the muzzle blast bouncing off the corners and surfaces of structures are heard. . . .
A listener cannot tell, from the sounds of a gunshot, when the gun was fired. He can determine only the times that elapse between the muzzle blast and each of its echoes. These elapsed times are called the echo-delay times. Because the echo travel times are uniquely related to the locations of the gun and the listener, the echo-delay times are unique to any given pair of those locations. Hence, if we know the temperature (and thus, the speed of sound) and the location of the echo-producing structures, echo-delay times can be used to characterize the sounds of a gunshot for any pair of shooter and listener locations. . . .
The "listener" that we have discussed, of course, could be either a human ear or a microphone. If a microphone receives the sounds and they are subsequently recorded, the recording becomes a picture of the event, not unlike a "fingerprint," that permanently characterizes the original gun and microphone locations.
Echo-delay times in such recordings can be measured easily and precisely by producing a graph of their waveforms on an oscillogram, or oscillograph. Such a graph is shown in figure 1. The narrow peaks represent individual sounds of brief duration (that is, impulse-sounds). The heights of the peaks correspond to the loudness of the impulse sounds; the spacing between peaks corresponds to the time that elapses between them. The largest of the impulse peaks is the muzzle blast. . . .
Using the fingerprint identification process as an analogy, if a latent fingerprint taken from a knife found protruding from a murder victim's body is given to the FBI for identification, it may be that no matching "known" print is on file at FBI headquarters and that the murderer cannot be immediately identified. Furthermore, the police may proceed to take fingerprint samples from all of the suspects in the case and find that none match the one found on the murder weapon. In the end, the latent fingerprint may not be identified.
Applying the analogy to the graphs of sounds, our problem was to see if any of a number of assumed pairs of shooter and microphone locations would produce a pattern of sounds whose graph would match the graph of the sounds in question on the DPD tape.
After numerous comparisons between the echo-delay times for the sounds on the DPD recording and various predicted patterns for assumed motorcycle and shooter locations that did not match, a combination of motorcycle and shooter locations was found which mathematically produced a predicted pattern that showed strong similarities to the pattern of impulses on the DPD tape. However, to determine with a high level of certainty if these two sequences of echo delay times, which were derived from different data, represented the same source, it was not enough to show that the sequences looked alike.
They had to be shown to be alike in an objective sense, that is, by use of a method of comparison that disregarded potentially misleading appearances. Such a method was provided by a computation of the binary correlation coefficient of the two sequences. The binary correlation coefficient of two sequences is a number that is exactly 1.0 if the sequences are identical and that rapidly approaches zero as they grow more dissimilar. As used in this analysis, the binary correlation coefficient takes into account the number of echo-delay times in each of the sequences and the number of echoes that coincide. Echoes in the two sequences are said to coincide if their delay times differ by a small amount. The smaller this amount, or "coincidence window," can be made while maintaining a high binary correlation coefficient, the greater will be the probability that the DPD sequence represents a gunshot from the grassy knoll. . . .
Two different comparisons were made between the sequence of echo-delay times on the DPD tape and the most similar sequence of predicted echo-delay times. One of the comparisons was between those recorded sounds that were significantly louder than the average background noise and those predicted echoes that would have been recorded with comparable loudness. In the other comparison, the delay times of all of the recorded sounds and of all of the predicted echoes, up to a total delay of 50 milliseconds from the muzzle blast, were compared. The computed binary correlation coefficient was found to be 0.79 for the first comparison and 0.75 for the second.
In both of the comparisons described above, the coincidence window was set at ±1 millisecond. That is. a measured echo-delay time and a predicted one were said to coincide only if they were no more than 1 millisecond apart. For sequences that correlated at levels greater than 0.7 with a coincidence window of ±1 millisecond, the statistical probability was 95 percent or more that the sequences represented the same source-a sound as loud as a gunshot from the grassy knoll. Put alternatively, the probability that the sounds on the DPD recording were generated by sources other than a sound as loud as a gunshot originating from the grassy knoll is 5 percent or less. . . .
If a gun was fired from the grassy knoll during the assassination, the would-be assassin reasonably could have used either a rifle or a pistol, since the target would have been less than 150 feet away. Since rifles typically fire bullets that travel faster than the speed of sound, the firing of a rifle generates two intermixed echo sequences composed of the echoes of the muzzle blast and the echoes of the continuously generated shock wave that is created by a bullet in supersonic flight. On the other hand, most pistol bullets do not fly at supersonic speeds. . . .
The BBN analysis indicated that the gun was in the vicinity of the grassy knoll. During the acoustic reconstruction experiment that was conducted by BBN in Dealey Plaza on August 20, 1978, shots were fired from behind the wooden stockade fence on the grassy knoll. This location was consistent with available eyewitness and earwitness testimony. It was a reasonable one since it afforded good visibility of Elm Street while providing good cover for the shooter of a gun. At any other location on the grassy knoll either the visibility or the cover would have been substantially poorer. . . .
We expected to be able. to predict echo-delay times to within ±1 millisecond for specified locations of a gun and a microphone. However, it was essential to verify that this accuracy would be achieved in practice and that the identified echo-producing objects would generate significant echoes in the region of interest on Elm Street. To test the procedure, we predicted the delay times of the echoes that would be received by a, microphone at the location of microphone 4 of array 3, as shown in figure 5, for a shot fired from the grassy knoll by the DPD shooter during the acoustic reconstruction experiment. We then compared the predicted echo-delay times to echo-delay times actually recorded on the BBN tape recording of the shot that was fired by the DPD shooter. At the time that the test shot was fired, the temperature in Dealey Plaza was approximately 90° Fahrenheit. Accordingly, the value used for the speed of sound was 1,150 feet per second. As discussed in section 4.1.5, the echo-delay time is computed by subtracting the muzzle blast travel time (185.2 msec.) from the echo travel time. The muzzle blast travel time is obtained by dividing the distance between the gun and the microphone in Dealey Plaza (213 feet) by the speed of sound. . . .
Using the methods described above, 26 echo paths were defined for 22 echo-producing objects. For some of these paths, the muzzle blast sound bounced off more than one echo-producing object. The echo-producing objects and echo paths are listed in tables 1 and 2. The travel times and the delay times for the predicted echoes are listed in table 3. Also listed are the echo-delay times determined by analysis of the time waveforms of the sounds received at microphone 4 of array 3 for the shot fired by the DPD shooter from the grassy knoll. These waveforms, which are shown in figure 6, were obtained by playing back the recording of the sounds that were picked up by the microphone, modifying the reproduced signal so as to approximate the effect that a microphone of the type used by the DPD in 1963 would have had on the signal, and then graphing the resulting signal. . . .
An analysis of the data listed in table 3 shows that the assumed locations were sufficiently accurate for the purpose of this test. The average absolute difference between the predicted and measured echo-delay times was 0.8 millisecond. The standard deviation of predicted 26 delay times about this average was 0.7 millisecond. These results are well within the accuracy required of the echo prediction procedure. . . .
The DPD radio dispatching system contained a circuit, that would have greatly affected the relative strengths of the recorded echoes of a muzzle blast. This circuit, the automatic gain control (AGC), limited the range of variations in the levels of signals by reducing the levels of received signals when they were too strong and increasing their levels when they were too weak. It responded very rapidly to a sudden increase in the level of a signal, but comparatively slowly to a sudden reduction in a signal level. Consequently, the response of the AGC to the sound of a muzzle blast would greatly reduce the recorded levels of echoes and background noise received shortly afterward. . . .
The high degree of correlation between the impulse and echo sequences does not preclude the possibility that the impulses were not the sounds of a gunshot. It is conceivable that a sequence of impulse sounds, derived from non-gunshot sources, was generated with time spacings that, by chance, corresponded within one one-thousandth of a second to those of echoes of a gunshot fired from the grassy knoll. However, the probability of such a chance occurrence is about 5 percent.
This calculation represents a highly conservative point of view, since it assumes that impulses can occur only in the two intervals in which echoes were observed to occur, these being the echo-delay range from 0 to 85 milliseconds and the range from 275 to 370 milliseconds. However, if the impulses in the DPD recording were not the echoes of a gunshot, they could also have occurred in the 190-millisecond timespan that separated these two intervals. Taking this timespan into account, the probability becomes considerably less than 5 percent that the match between the recorded impulses and the predicted echoes occurred by chance.
Thus, the probability is 95 percent or more that the impulses and echoes have the same source--a gunshot from the grassy knoll. Stated differently, the odds are less than 1 in 20 that the impulses and echoes were not caused by a gunshot from the grassy knoll, and at least 20 to 1 that they were. (8 HSCA 6-7, 9-10, 16, 22, 24-26, 30, 32)
I see no mention (in the quoted text) of a dictabelt recorder being part of the recording chain in the controlled setup (NYC/NYPD) or any other controlled setup to verify what the dictabelt is capable of, but I could have missed it.
I'm not interested what they think they heard or measured on the original recording.
* When you calculate the speed of the dictabelt motorcycle based on the echo correlations with the test-firing impulses, you get a speed that is almost identical to the average speed of JFK’s limo. The distance from the first matching microphone to the last was 143 feet. The time between the first and last gunshot impulse on the dictabelt is 8.3 seconds. In order for the motorcycle with the stuck mike to cover 143 feet in 8.3 seconds, it would have had to travel at a speed of right around 11.7 mph. This speed fits almost perfectly with the FBI's conclusion that Kennedy’s limo averaged 11.3 mph on Elm Street. If this is a “coincidence,” it is an amazing, stunning coincidence.
* Acoustical experts Weiss and Aschkenasy determined that the odds that the correlations between the dictabelt grassy knoll shot impulse and the test-firing grassy knoll impulse were a coincidence were “less than 1 in 20” (8 HSCA 32).
Incidentally, Weiss and Aschkenasy said that before they began their research, they did not believe there were any shots on the dictabelt, much less four or more.
In limiting the test firings to two locations, Blakey ruled out the possibility that any of the unmatched sounds on the dictabelt could be matched with impulses of shots fired from other locations, such as from the nearby Dal-Tex Building or the County Records Building, both of which would have provided logical sniper positions. (Interestingly, Mafia man Eugene Brading was arrested in the Dal-Tex Building shortly after the assassination. Just a "coincidence", right?)
I didn't think less than an expert's opinion counted...
I see no mention (in the quoted text) of a dictabelt recorder being part of the recording chain in the controlled setup (NYC/NYPD) or any other controlled setup to verify what the dictabelt is capable of, but I could have missed it.
I'm not interested what they think they heard or measured on the original recording.
No mention on the NYC/NYPD using a Dictabelt recorder. And no mention of the NYC/NYPC tests showing the recordings they did get were audible or inaudible.
Common sense says a recording of gunshots should be audible.
In support of this, it was reported that the Dallas police noticed on their daily Dictabelt recording from 1978, audible, not inaudible, but audible sounds from the 1978 acoustic test firings. Very unlike the inaudible N-waves on the 1963 recording. But the acoustic experts had no interest in what a Dictabelt would record, only what their instruments would record. But their instruments weren’t there in 1963, so no direct comparison could be made, as could have been done had they made use of the Dictabelt system that was still there in 1978.
1. The “gunshots” on the 1963 recording are inaudible, but it appears on the 1978 recording they were audible.
Now it was perfectly clear that these sounds were not clearly audible. There is in the field of detection theory a favorite approach called matched filtering. The matched filter is a device that is used to detect events that you have some understanding of, even though they are subaudible. Matched filters are used in radar sets commonly to detect the presence of impulsive signals in noise, even though they are not visible or audible in the raw data. There was reason to believe that applying these techniques we might be able to detect the impulsive sounds of gunfire.
The most serious problem was the motorcycle noise. There is a way to help reduce that. It is a technique called adaptive filtering. It considers that the motorcycle is a repetitive device . As the cylinders fire, they do so periodically. The adaptive filter can learn to understand the event and project what will happen the next time the piston fires and subtract that noise out from the tape.
We thought once the adaptive filtering was conducted, the tape might then be noise-free enough to attempt a detection of the sounds of gunfire. . . . .
Initially we listened to the whole tape and we found at one point on the tape a 5 1/2-minute segment in which the sound of a motorcycle engine and other noises were heard continuously. This particular 5 1/2-minute segment was the period of the stuck microphone button that Professor Blakey described earlier.
The sound in that 5 1/2-minutes was mostly motorcycle noise. . . .
Now, as I said, we realized from the outset that we were seeking to detect sub-audible events, or at least not audibly recognizable events, and this is helped by looking at the electrical waveform that represents the sounds in a form called a waveform chart. So the first thing we did was to digitize the sounds in this 5 1/2-minute tape recording to form a computer file of the information contained by that digitalization, and then plot out a chart showing the waveform on the tape. (2 H 18, 27)
2. The “gunshots” appear to occur at the wrong time, about when Sheriff Decker says “Hold everything secure”.
3. The predicted location of where the motorcycle that recorded these shots occurred, does not have a motorcycle there, or anywhere within 100 feet of that location, the intersection of Houston and Elm.
As I have explained, the pattern of the N-wave shed from the bullet is distinct, so the echo pattern at any one point depends upon the direction in which the rifle is pointing, as well as the place where it is fired from. (2 H 48)
We presumed nothing about the location of the motorcycle or its speed or even direction of motion. The matches were made without any presumption whatsoever about the position of the motorcycle, in fact, of course, without any knowledge that the motorcycle was even there.
After having made the matches, however, the position, I should say, the location of the microphones through which we found matches did in fact progress down the motorcade route at the times that the four subsequent periods on the tape showed matches. And as I indicated previously, the locations of the microphones where the matches were found at the four different times were moving down the motorcade route at approximately 11 miles an hour. (2 H 70)
Upon reading the NAS report, we did a brief analysis of the Audograph dub that was made by the NAS Committee and loaned to us by them. We found some enigmatic features of this recording that occur at about the time that individuals react to the assassination. Therefore, we have doubt about the time synchronization of events on that recording, and so we doubt that the Barber hypothesis is proven. The NAS Committee did not examine the several items of evidence that corroborated our original findings, so that we still agree with the House Select Committee on Assassinations conclusion that our findings were corroborated. (Letter from Barger to Robert Blakey, February 18, 1983)
No. When did I say that?
I don't doubt it, I question why the "experts" didn't establish a baseline for what the Dicta-belt would record in case of a gunshot under various conditions.
That you can't hear?
How would I know. Have you seen the wave forms KNOWN to be from gunshots on a Dicta-belt?
What they assumed to be gunshots.
Correct, unless they had a Dicta-belt reference. I certainly do, that's why I'm pointing out their method was unsound. yadayada
They supplied no experimental evidence said impulses would record on a Dicta-belt in a way they assumed.
The gain control (AGC) discussed is not that of the Dicta-belt machine. If you believe it is be specific in you quote.
The DPD radio dispatching system contained a circuit, that would have greatly affected the relative strengths of the recorded echoes of a muzzle blast. This circuit, the automatic gain control (AGC), limited the range of variations in the levels of signals by reducing the levels of received signals when they were too strong and increasing their levels when they were too weak. It responded very rapidly to a sudden increase in the level of a signal, but comparatively slowly to a sudden reduction in a signal level. Consequently, the response of the AGC to the sound of a muzzle blast would greatly reduce the recorded levels of echoes and background noise received shortly afterward. Progressively during the next 100 milliseconds, the AGC would allow the recorded levels of received signals to increase until full amplification was finally restored. The effect on the predicted echoes would be to make the recorded levels of late-arriving echoes verv nearly the same as those of the early ones. (8 HSCA 30)
No, we don't know how sound in the case of gunshots were recorded since no baseline recording of gunshots involving a Dicta-belt machine was conducted.
http://mcadams.posc.mu.edu/odell/
Neither this nor the original NRC study attempted to refute the core evidence at the heart of the HSCA conclusion: the fact that the suspect sounds on the police recording matched the test shots fired in Dealey Plaza, and that the matching data was ordered in a way that would not have happened if the matches were spurious. (p. 613)
Although no films show the specified locations at the requisite times, a motorcycle ridden by a patrolman named H. B. McClain was in a position both before and after the shooting such that with a reasonable trajectory he could have been in the specified locations. (p. 687)
No control for all this stuff was established on a dicta-belt. Deal with it.
Fine, then show me the specs for the Dicta-belt recording gunshots and inaudible pulses.
Straw man arguments doesn't work. Not my claim.
No matter what the critics say they cannot make the pulse patterns attributed to gunfire vanish from the acoustic records. These patterns contain very special pulses that distinguish themselves from all the other snaps, crackles or pops. I call these special signals limiting pulses.
Playing a wave file of these limiting pulses at progressively slower speeds provides audible evidence of the special nature of these pulses.
Reducing playing speed dramatically lowers the pitch of the voice and has a similar effect upon a brief heterodyne and the background noise. However, the pitches of the limiting pulses initially resist lowering and change slightly at greatly reduced playing speeds. This demonstration shows that the high frequency contents of the limiting pulses are widely dispersed and extremely rich. These uncommon characteristics are further evidence that these special pulses are the responses of the radio system to impulses generated by the limiting circuit in the audio stage of the transmitter.
BBN documented a level of 100 db re 2 X 10-5 Newton per square meter at the microphone as the threshold for activation of the limiting circuit. This means that ears near that microphone would have heard sounds reminiscent of moderately distant gunfire.
Two choices arise. One may assert that the Dictaphone recorded gunshots on the Dictabelt or a studio added the limiting pulses and made an untrue acoustic record. . . .
The fundamental problem with this conclusion [that the crosstalk was recorded through a receiver with AGC] is the presented evidence does not show that the cross talk recordings were made through a radio receiver. Although the Committee on Ballistic Acoustics [the formal name of the NAS-NRC-Ramsey panel] should have tested heterodynes for frequency modulation as conclusive evidence of the by-radio nature of the cross talk, they pursued fallacious arguments. In fact, a quantitative detail provided by the committee showed AGC acted on audio. Even worse, they concentrated on attack characteristics that are ambiguous evidence of AGC action and misinterpreted the decay characteristics, which showed AGC acted at two or more places within the system. Not surprising the Committee on Ballistic Acoustics began by confusing the subject that provided a technically correct method of showing by-radio nature of the cross talk. . . .
In a communications system, frequencies below one thousand hertz contain most of the audio power. Now a gain control circuit requires many and perhaps tens of milliseconds to sample a few cycles. Without doubt, the sluggish decrease in cross talk intensity conclusively demonstrates the by-audio nature of the change.
The Committee on Ballistic Acoustics mistakenly attributed every decrease in cross talk volumes to AGC actions in response to heterodynes. . . .
Contrary to the declaration of the Watson Research Center, the frequency response of Channel-I was adequate to respond to the Channel-II brieftone. In fact, spectrographs of Bellah's broadcast and its crosstalk show the narrower frequency response of Channel-I attenuated the brieftone by less than four decibels relative to the voice.
Similarly a brieftone mars Decker's Channel-II hold everything secure broadcast. In both cases the brieftones are excessively loud signals and only their narrowband characters prevent them from obscuring the broadcasts.
Unlike the Bellah crosstalk where the loudness of the brieftone is comparable with the voice, the alleged Decker crosstalk contains no audible nor measurable brieftone.
The missing brieftone is the first clue that the alleged Decker crosstalk does not match the corresponding portion of the Decker broadcast while the badly garbled voice of the alleged Decker crosstalk that contrasts sharply with the clarity of the Bellah crosstalk is the second hint. (https://jfk.boards.net/thread/201/problems-acoustic-evidence)
Quote from: Joe Elliott on September 09, 2020, 01:44:14 AM
Question about Dr. Donald Thomas’s Dictabelt Offset Hypothesis
The “Hold Everything Secure” phrase, which was said about a minute after the assassination, and the “four impulse patterns” occur at about the same time on the Dictabelt recording. Dr. Donald Thomas explained this away by saying the two channels could drift apart from each other by a minute.
Would you have a source for this "offset" being explained (away)?
Mr. Elliott certainly got one thing right: your arguments always result in a copy-paste circus and now it's Herbert Blenner's turn.
I doubt you actually understand what he's saying, he just happens to support your case.
I know of Blenner and consider him one of the worst technical writers I've encountered. It's a mystery to me what he's driving at and what he's trying to confirm or debunk.
I'm not saying he doesn't know his stuff, I just don't have the patience to deal with him.
BTW, being unfamiliar with the term specs tells me you haven't got a clue about audio equipment
and I'll bet you have no clue whatsoever how the circuitry of the dictabelt machine would affect the input signal to be recorded.
Reading just the first few pages of the HSCA report Vol. III explains a lot. It's unclear in the Foreword what "authorized" means, but if they (BBN) were commissioned I hope they were handsomely paid. It's evident from section 1.2 they were provided three tapes containing Hi-Fi recorded stuff and they seemed to have blind faith in those tapes. Moving on to section 1.7 (p11) it's clear that the quality of the dictabelt recording was so bad that they had to speculate that what they termed "continuous noise" was believed to be the sound of a motorcycle engine. This is repeated on page 12. It immediately raises the question why the noise on the Hi-Fi recording could not be identified as engine noise from a bike and that didn't bother them? Especially in view of this found on a wiki page (I know, it's wiki and the source is Bugliosi) https://en.wikipedia.org/wiki/John_F._Kennedy_assassination_Dictabelt_recording):
There's nothing to disagree about, I'm stating the facts.
Okay, let's see if we can clear this up. We need to understand that the dictabelt machine was the medium on which the sounds were recorded; the dictabelt itself did not control how the sounds were processed before they arrived, before they were recorded. The dictabelt received sounds from the DPD dispatch system. The DPD dispatch system included an AGC circuit, among other circuits. The AGC circuit greatly affected how sounds were processed before they arrived at the dictabelt. I quote from the Weiss and Aschkenasy report to the HSCA:
I doubt you actually understand what he's saying, he just happens to support your case. I know of Blenner and consider him one of the worst technical writers I've encountered. It's a mystery to me what he's driving at and what he's trying to confirm or debunk. I'm not saying he doesn't know his stuff, I just don't have the patience to deal with him.
Mr. SPersonIVAN.
Now, the next line labeled momentum lost, all I have done is taken the product of the mass-this is 162 grains divided by 7,000 - which gives us the mass of the bullet in pounds. Multiply that mass of bullet in pounds times 800 - feet per second, the velocity lost, and we have a quantity, an unusual quantity, 18.4 pound feet per second of momentum which has been deposited by the bullet.
Gentlemen,
I have a question about the acoustical evidence that I hope can be answered.
On the one hand, we have video evidence like the Zapruder film but they contain no audio. They are all mute.
On the other hand we have the dictabelt recording of 4 to 6 shots fired at the President at Dealey Plaza.
Can both video and audio files be combined, or overlayed, or compared? If frame 313 of the Zapruder film is taken as a starting point for any one impulse on the dictabelt recording, then presumably we could shift the graph of those impulses to match with the frame. By determining which impulse is linked to frame 313, a shooting scenario could be established, but if any one impulse on the recording can not be matched to any reactions by the President or the Governor then the dictabelt recording interpretation is flawed?
This is very hard for me to explain or even phrase properly in a foreign language. Please forgive any errors. I hope however that you understand the basics of my question. Dr. Thomas's presentation is very compelling, as are the HSCA's, but since I am not an expert on the matter I am perhaps easily impressed.
@ Michael Griffith
Thanks for your extensive responses in this thread. I don't understand it all, but I am learning because of your contributions. Please keep up the good work!
There is a surprising--surprising to me, at least--degree of correlation between the timing of the gunshot impulse patterns on the dictabelt and the timing of the reactions to gunfire in the Zapruder film. Many scholars have discussed this subject.
Personally, I have never bothered much with this issue because I think there is convincing evidence that the current Zapruder film has been altered and is shorter than the original. Yet, there are correlations in timing between the dictabelt gunshots and the gunfire reactions in the Zapruder film.
Interestingly, the HSCA acoustical experts made one math error that exaggerated the chances that the correlations between the dictabelt shots and the Dealey Plaza test-firing shots could be a coincidence. Based on this math error, they calculated that the odds that the correlations are a coincidence are less than 1 in 20, or less than 5%. Those are still long odds, to be sure. But, in actuality, the odds that the correlations are a coincidence are 1 in 100,000 (Thomas, Hear No Evil, pp. 628-632).
Gentlemen,
I have a question about the acoustical evidence that I hope can be answered.
On the one hand, we have video evidence like the Zapruder film but they contain no audio. They are all mute.
On the other hand we have the dictabelt recording of 4 to 6 shots fired at the President at Dealey Plaza.
Can both video and audio files be combined, or overlayed, or compared? If frame 313 of the Zapruder film is taken as a starting point for any one impulse on the dictabelt recording, then presumably we could shift the graph of those impulses to match with the frame. By determining which impulse is linked to frame 313, a shooting scenario could be established, but if any one impulse on the recording can not be matched to any reactions by the President or the Governor then the dictabelt recording interpretation is flawed?
This is very hard for me to explain or even phrase properly in a foreign language. Please forgive any errors. I hope however that you understand the basics of my question. Dr. Thomas's presentation is very compelling, as are the HSCA's, but since I am not an expert on the matter I am perhaps easily impressed.
@ Michael Griffith
Thanks for your extensive responses in this thread. I don't understand it all, but I am learning because of your contributions. Please keep up the good work!
There is a surprising--surprising to me, at least--degree of correlation between the timing of the gunshot impulse patterns on the dictabelt and the timing of the reactions to gunfire in the Zapruder film. Many scholars have discussed this subject.
This is a very good question. And you may hope that it will be answered. But I fear your hopes may be in vain. Why? Because CTers don’t like to answer this question. [SNIP]
Quote from Otto Beck:
Any believer in a faked Z-film should be greatly concerned if the acoustical evidence lines up with the Z-film as we know it.
Quote from: Joffrey van de Wiel on Today at 04:54:51 PM
I have a question about the acoustical evidence that I hope can be answered. On the one hand, we have video evidence like the Zapruder film but they contain no audio. They are all mute. On the other hand we have the dictabelt recording of 4 to 6 shots fired at the President at Dealey Plaza. Can both video and audio files be combined, or overlayed, or compared?
Oh my goodness, this is just ignorant. Partner, if you don't like being called out for ignorance, then you really need to stop posting until you know what in the world you're talking about.
Now, FYI, conspiracy theorists have written hundreds of pages on correlating the dictabelt gunshots with gunfire reactions in the Zapruder film. The HSCA discussed this very subject in its final report. Both of the expert consultant reports to the HSCA--the BBN report and the W&A report--discussed this issue; in fact, correlation with the Zapruder film was one of the criteria for identifying gunshot impulse patterns on the dictabelt, for crying out loud. How on earth can you not know this and yet pretend to credibly discuss the acoustical evidence?
Well, keep in mind that the alteration probably only removed 1-2 seconds' worth of frames from the shooting sequence in the Zapruder film. This would explain why the dictabelt gunshots do line up pretty well with the Zapruder film.
Joffrey, I recommend you get Dr. Thomas's book Hear No Evil. It includes four chapters on the acoustical evidence, totaling 131 pages, including an extensive discussion on the correlation between the dictabelt gunshot impulse patterns and the gunfire reactions in the Zapruder film. Dr. Thomas provides a very condensed version of this discussion in the following article:
https://www.maryferrell.org/pages/Essay_-_Acoustics_Overview_and_History_-_part_2.html
Well, keep in mind that the alteration probably only removed 1-2 seconds' worth of frames from the shooting sequence in the Zapruder film. This would explain why the dictabelt gunshots do line up pretty well with the Zapruder film.
Table 1.- Synchronization of Putative Shots to Zapruder Frames
(https://sites.google.com/site/jfkforum/misc/newsgroup/spacers/dot_clear.gif)
Acoustic
Event
(https://sites.google.com/site/jfkforum/misc/newsgroup/spacers/dot_clear.gif)Tape
TimeTape-Time
IntervalReal
TimeZ-Frame
EquivalentShot
OriginA 136.2 - 8.7 9.1 Z-147 No Match B 137.7 - 7.2 7.5 Z-175 TSBD C 139.2 - 5.6 5.8 Z-204 Rogue Shot D 140.3 - 4.6 4.8 Z-224 TSBD E (145.1) 144.9 0 0 Z-312 KNOLL F 145.6 + 0.7 0.7 Z-326 TSBD
Joe, it would be easier to follow your argument by using the actual material published by Dr. Thomas and object to what you believe is wrong. One source of "Hear No Evil" is here: http://www.whokilledjfk.net/hear_no_evil.htm
If you go to section FILMED EVIDENCE OF THE MOTORCYCLE you have a table of shots and Z-frames (Table 1). It says that "Tape Times from BBN Report Table 2.", which I haven't checked, but the times you're asking for should be there.
Edit: unfortunately the figures don't display in the url I listed above.
Joe and Otto, if you want to educate yourselves on the basics of the acoustical evidence, I suggest you watch the following video made by Dr. Thomas in 2014. He covers a lot of the evidence that the dictabelt contains gunfire--not all of it, but a lot of it. He also addresses the crosstalk issue and the Sonalysts study. You'll want to watch the Q&A segment as well, which includes questions from Dr. Mantik and from one of the HSCA staffers who worked with the HSCA acoustical experts. The video is only 40 minutes long and includes lots of graphics.
https://aarclibrary.org/dr-donald-b-thomas-jfk-acoustical-evidence-challenge-and-corroboration/
Quote from: Otto Beck on September 16, 2020, 09:48:35 AM
Joe, it would be easier to follow your argument by using the actual material published by Dr. Thomas and object to what you believe is wrong. One source of "Hear No Evil" is here: http://www.whokilledjfk.net/hear_no_evil.htm
If you go to section FILMED EVIDENCE OF THE MOTORCYCLE you have a table of shots and Z-frames (Table 1). It says that "Tape Times from BBN Report Table 2.", which I haven't checked, but the times you're asking for should be there.
Edit: unfortunately the figures don't display in the url I listed above.
Thank you Otto. This information is most helpful. I’ll start another thread on it in a day or two. At a glance, I can see why Mr. Griffith was not giving us this information directly, even though, . . .
the initial impression, is that it matches up with the Zapruder film. But I will show that this is bogus.
Question for Joffrey van de Wiel
Has Mr. Griffith answered your questions about the number of the “shots” on the Dictabelt recording?
And the timing of these “shots”?
And the source of each “shot” (TSBD, Grassy Knoll, etc.)?
And which Zapruder frame each “shot” corresponds to?
Have you found that there is the excellent correlation between the answers that Mr. Griffith has given you and the Zapruder film as he claims we can find?
Or have you found that Mr. Griffith has been evasive, as I predicted.
And if you haven’t found Mr. Griffith to be evasive, how many “gunshots” are to be found on the Dictabelt recording?
Otto Beck
If the Decker/Fisher pair result from cross talk (coming from Channel-2) and Channel-1 records uninterrupted in real time there is no way the Decker/Fisher pair on Channel-2 can be spaced further apart in time that on Channel-1.
If synchronized using the Fischer broadcast the Decker arrives too late on CH-2, if synchronized using the Decker broadcast the Fischer broadcast on CH-1 evidently can't be simulcast.
Since CH-2 is voice activated, simulcasts must be equally or closer spaced on CH-2, something is not right here.
Why no, I don’t mind being called ignorant from someone who has been as evasive as you.
Question for Joffrey van de Wiel
Has Mr. Griffith answered your questions about the number of the “shots” on the Dictabelt recording?
And the timing of these “shots”?
And the source of each “shot” (TSBD, Grassy Knoll, etc.)?
And which Zapruder frame each “shot” corresponds to?
Have you found that there is the excellent correlation between the answers that Mr. Griffith has given you and the Zapruder film as he claims we can find?
Or have you found that Mr. Griffith has been evasive, as I predicted.
And if you haven’t found Mr. Griffith to be evasive, how many “gunshots” are to be found on the Dictabelt recording?
And Joffrey, if you have found Mr. Griffith to be evasive, don’t waste your time and money on Dr. Thomas’s “Hear No Evil”. You will find that Dr. Thomas does not answer these questions either, and is just as evasive as Mr. Griffith.
To the human ear, the tapes and Dictabelts contain no discernible sounds of gunfire. The dispatcher's voice notations of the time of day indicate that channel 2 apparently was not in use during the period when the shots were fired. Channel 1 transmissions, however, were inadvertently being recorded from a motorcycle or other police vehicle whose radio transmission switch was stuck in the "on" position.(10) BBN was asked to examine the channel 1 Dictabelts and the tape that was made of them to see if it could determine: (1) if they were, in fact, recorded transmissions from a motorcycle with a microphone stuck in the "on" position in Dealey Plaza; (2) if the sounds of shots had been, in fact, recorded; (3) the number of shots; (4) the time interval between the shots; (5) the location of the weapon or weapons used to fire the shots; and (6) the type of weapon or weapons used.
BBN converted the sounds on the tape into digitized waveforms and produced a visual representation of the waveforms.(11) By employing sophisticated electronic filters, BBN filtered out "repetitive noise," such as repeated firings of the pistons of the motorcycle engine.(12) It then examined the tape for "sequences of impulses" that might be significant. (A "sequence of impulses" might be caused by a loud noise--such as gunfire--followed by the echoes from that loud noise.) Six sequences of impulses that could have been caused by a noise such as gunfire were initially identified as having been transmitted over channel 1.(13) Thus, they warranted further analysis.
These six sequences of impulses, or impulse patterns, were subjected to preliminary screening tests to determine if any could be conclusively determined not to have been caused by gunfire during the assassination. The screening tests were designed to answer the following questions:(14)
-- Do the impulse patterns, in fact, occur during the period of the assassination?
-- Are the impulse patterns unique to the period of the assassination?
-- Does the span of time of the impulse patterns approximate the duration of the assassination as indicated by a preliminary analysis of the Zapruder film? (Are there at least 5.6 seconds between the first and last impulse? 4)
-- Does the shape of the impulse patterns resemble the shape of impulse patterns produced when the sound of gunfire is recorded through a radio transmission system comparable to the one used the Dallas police dispatch network?
-- Are the amplitudes of the impulse patterns similar to those produced when the sound of gunfire is recorded through a transmission system comparable to the one used for the Dallas police dispatch network?
All six impulse patterns passed the preliminary screening tests.(15)
BBN next recommended that the committee conduct an acoustical reconstruction of the assassination in Dealey Plaza to determine if any of the six impulse patterns on the dispatch tape were caused by shots and, if so, if the shots were fired from the Texas School Book Depository or the grassy knoll.(16) The reconstruction would entail firing from two locations in Dealey Plaza--the depository and the knoll--at particular target locations and recording the sounds through numerous microphones. The purpose was to determine if the sequences of impulses recorded during the reconstruction would match any of those on the dispatch tape. If so, it would be possible to determine if the impulse patterns on the dispatch tape were caused by shots fired during the assassination from shooter locations in the depository and on the knoll.(17). . . .
. . . it was deemed judicious to seek an independent review of Barger's analysis before proceeding with the acoustical reconstruction. So, in July 1978, the committee contacted the Acoustical Society of America to solicit recommendations for persons qualified to review the BBN analysis and the proposed Dallas reconstruction. The society recommended a number of individuals, and the committee selected Prof. Mark Weiss of Queens College of the City University of New York and his research associate, Ernest Aschkenasy. Professor Weiss had worked on numerous acoustical projects. He had served, for example, on the panel of technical experts appointed by Judge John J. Sirica to examine the White House tape recordings in conjunction with the Watergate grand jury investigation. Aschkenasy had specialized in developing computer programs for analyzing large volumes of acoustical data. . . .
A recording was made of the sounds received at each microphone location during each test shot, making a total of 432 recordings of impulse sequences (36 microphone locations times 12 shots), or "acoustical fingerprints," for various target-shooter-microphone combinations. Each recorded acoustical fingerprint was then compared with each of the six impulse patterns on the channel 1 dispatch tape to see if and how well the significant points in each impulse pattern matched up. The process required a total of 2,592 comparisons (432 recordings of impulse sequences times six impulse patterns), an extensive effort that was not completed until 4 days before Barger was to testify at a committee public hearing on September 11, 1978.(26)
The time of the arrival of the impulses, or echoes, in each sequence of impulses was the characteristic being compared, not the shape, amplitude or any other characteristic of the impulses or sequence.(27) If a point (representing time of arrival of an echo) in a sequence of the 1963 dispatch tape could be correlated within plus or minus 6/1,000 of a second to a point in a sequence of the reconstruction, it was considered a match.(28)
A plus or minus 6/1,000 of a second "window" was chosen, because the exact location of the motorcycle was not known. Since the microphones were placed 18 feet apart in the 1978 reconstruction, no microphone was expected to be in the exact location of the motorcycle microphone during the assassination in 1963. Since the location was not apt to be exactly the same, and the time of arrival of the echo is unique at each spot, the +-6/1,000 of a second "window" would allow for the contingency that the motorcycle was near, but not exactly at, one of the microphone locations selected for the reconstruction.(29)
Those sequences of impulses that had a sufficiently high number of points that matched (a "score" or correlation coefficient of .6 or higher) were considered significant.(30) The "score" or correlation coefficient was set at this level to insure finding all sequences that might represent a true indication that the 1963 dispatch tape contained gunfire. Setting it at this level, however, also allowed a sequence of impulses on the dispatch tape that might have been caused by random noise or other factors to be considered a match and therefore significant.(31) Such a match, since it did not in fact represent a true indication of gunfire on the 1963 dispatch tape, would be considered an "invalid match."(32)
Of the 2,592 comparisons between the six sequences of impulses on the 1963 police dispatch tape and the sequences obtained during the acoustical reconstruction in August 1978, 15 had a sufficient number of matching points (a correlation coefficient of .6 or higher) to be considered significant.(33) The first and sixth sequence of impulses on the dispatch tape had no matches with a correlation coefficient over .5. The second sequence of impulses on the dispatch tape had four significant matches, the third sequence had five, the fourth sequence had three, and the fifth sequence had three.(34) Accordingly, impulses one and six on the dispatch tape did not pass the most rigorous acoustical test and were deemed not to have been caused by gunfire from the Texas School Book Depository or grassy knoll.(35) Additional analysis of the remaining four impulse sequences was still necessary before any of them could be considered as probably representing gunfire from the Texas School Book Depository or the grassy knoll.
The locations of the microphones that recorded the matches in the 1978 reconstruction were plotted on a graph that depicted time and distance. It was observed that the location of the microphones at which matches were recorded tended to cluster around a line on the graph that was, in fact, consistent with the approximate speed of the motorcade (11 mph), as estimated from the Zapruder film.(36) For example, of the 36 microphones placed along the motorcade route, the one that recorded the sequence of impulses that matched the third impulse on the 1963 dispatch tape was farther along the route than the one that recorded the impulses that matched the second impulse on the dispatch tape. The location of the microphones was such, it was further observed, that a motorcycle traveling at approximately 11 miles per hour would cover the distance between two microphones in the elapsed time between impulses on the dispatch tape. This relationship between the location of the microphones and the time between impulses was consistent for the four impulses on the dispatch tape, a very strong indication, the committee found, that the impulses on the 1963 dispatch tape were picked up by a transmitter on a motorcycle or other vehicle as it proceeded along the motorcade route. Applying a statistical formula, Barger estimated that since the microphones clustered around a line representing the speed of the motorcade, there was a 99 percent probability that the Dallas police dispatch tape did, in fact, contain impulses transmitted by a microphone in the motorcade in Dealey Plaza during the assassination.(37). . . .
In mid-September 1978, the committee asked Weiss and Aschkenasy, the acoustical analysts who had reviewed Barger's work, if they could go beyond what Barger had done to determine with greater certainty if there had been a shot from the grassy knoll. Weiss and Aschkenasy conceived an analytical extension of Barger's work that might enable them to refine the probability estimate.(45) They studied Dealey Plaza to determine which structures were most got to have caused the echoes received by the microphone in the 1978 acoustical reconstruction that had recorded the match to the shot from the grassy knoll. They verified and refined their identifications of echo-generating structures by examining the results of the reconstruction. And like BBN, since they were analyzing the arrival time of echoes, they made allowances for the temperature differential, because air temperature affects the speed of sound.(46) Barger then reviewed and verified the identification of echo-generating sources by Weiss and Aschkenasy.(47)
Once they had identified the echo-generating sources for a shot from the vicinity of the grassy knoll and a microphone located near the point indicated by Barger's tests, it was possible for Weiss and Aschkenasy to predict precisely what impulse sequences (sound fingerprints) would have been created by various specific shooter and microphone locations in 1963.(48) (The major structures in Dealey Plaza in 1978 were located as they had been in 1963.) Weiss and Aschkenasy determined the time of sound travel for a series of sound triangles whose three points were shooter location, microphone location and echo-generating structure location. While the location of the structures would remain constant, the different combinations of shooter and microphone locations would each produce a unique sound travel pattern, or sound fingerprint.(49) Using this procedure, Weiss and Aschkenasy could compare acoustical fingerprints for numerous precise points in the grassy knoll area with the segment identified by Barger on the dispatch tape as possibly reflecting a shot fired from the knoll.(50) 10
Because Weiss and Aschkenasy could analytically construct what the impulse sequences would be at numerous specific shooter and microphone locations, they decided to look for a match to the 1963 police dispatch tape that correlated to within ±1/1.000 of a second, as opposed to +-6/1.000) of a second, as Barger had done.(51) By looking for a match with such precision, they considerably reduced the possibility that any match they found could have been caused by random or other noise,(52) thus substantially reducing the percentage probability of an invalid match. . . .
Approximately 10 feet from the point on the grassy knoll that was picked as the shooter location in the 1978 reconstruction and four feet from a microphone location which, Barger found, recorded a shot that matched the dispatch tape within +-6/1,000 of a second, Weiss and Aschkenasy found a combination of shooter and microphone locations they needed to solve the problem. It represented the initial position of a microphone that would have received a series of impulses matching those on the dispatch tape to within +-1/1.000 of a second. The microphone would have been mounted on a vehicle that was moving along the motorcade route at 11 miles per hour.
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.11 On shot four, Weiss and Aschkenasy found no such distortion.(55) The analysts' ability to predict the effect of the windshield on the impulses found on the dispatch tape, and having their predictions confirmed by the tape, indicated further that the microphone was mounted on a motorcycle in Dealey Plaza and that it had transmitted the sounds of the shots fired during the assassination.
Since Weiss and Aschkenasy were able to obtain a match to within +-1/1,000 of a second, the probability that such a match could occur by random chance was slight. Specifically, they mathematically computed that, with a certainty factor of 95 percent or better, there was a shot fired at the Presidential limousine from the grassy knoll.(56)
Barger independently reviewed the analysis performed by Weiss and Aschkenasy and concluded that their analytical procedures were correct.(57) Barger and the staff at BBN also confirmed that there was a 95 percent chance that at the time of the assassination a noise as loud as a rifle shot was produced at the grassy knoll. When questioned about what could cause such a noise if it were not a shot, Barger noted it had to be something capable of causing a very loud noise--greater than a single firecracker.(58) Further, given the echo patterns obtained, the noise had to have originated at the very spot behind the picket fence on the grassy knoll that had been identified,(59) indicating that it could not have been a backfire from a motorcycle in the motorcade.(60)
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.(61) 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.(62) 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.(63) 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.(64) (HSCA report, pp. 68-75)
2) The open microphone did not record any gunshots;
3) The impulses shown on the audiograph are not gunshots but random impulses created by ambient noise;
The points of contention are:
1) There was no microphone stuck on the 'transmit' position in the motorcade, and if there was, it was nowhere near Dealey Plaza at 12:30 p.m.;
2) The open microphone did not record any gunshots;
3) The impulses shown on the audiograph are not gunshots but random impulses created by ambient noise;
4) The dictabelt recording can not be matched to the Zapruder film because it has been altered;
5) The four to six shots recorded by the dictabelt contradict the Warren Commission's findings therefore it can not possibly be true;
6) Some gunshot impulses on the recording can not be matched to any test shots, therefore the acoustic evidence is invalid.
Speaking of the WC, we now know that the commission had an analysis done on a KBOX radio station recording that was made in Dealey Plaza during the assassination.
Joe, it would be easier to follow your argument by using the actual material published by Dr. Thomas and object to what you believe is wrong. One source of "Hear No Evil" is here: http://www.whokilledjfk.net/hear_no_evil.htm
If you go to section FILMED EVIDENCE OF THE MOTORCYCLE you have a table of shots and Z-frames (Table 1). It says that "Tape Times from BBN Report Table 2.", which I haven't checked, but the times you're asking for should be there.
Edit: unfortunately the figures don't display in the url I listed above.
Thank you Otto. This information is most helpful. I’ll start another thread on it in a day or two. At a glance, I can see why Mr. Griffith was not giving us this information directly, even though, the initial impression, is that it matches up with the Zapruder film. But I will show that this is bogus.
What a bunch of lying nonsense. I have provided links to Dr. Thomas's articles in several of my replies. I've also provided citations from his book in some of my replies. I've also provided a link to one of Dr. Thomas's videos on the acoustical evidence. Just a few replies ago, I provided a link to one of Dr. Thomas's discussions on correlating the dictabelt and the Zapruder film. I also cited the pages in his book where he discusses this issue.
The points of contention are:
1) There was no microphone stuck on the 'transmit' position in the motorcade, and if there was, it was nowhere near Dealey Plaza at 12:30 p.m.;
1. We know this is wrong because the Channel 2 dispatcher told all the patrolmen that a patrolman "up on Stemmons" had his mike stuck on, and he asked them to try to find him and get him to shut off his mike. The "up on Stemmons" comment is evidence that McClain was the one with the stuck mike.
2) The open microphone did not record any gunshots;
Dr. BARGER - Yes. We examined the full 234 linear feet of the waveform representing the output of the channel 1 recording when the button was stuck to see if there were any other impulsive patterns that occurred that were similar to these that we are looking at on channel 1. We found that there was one other sequence of impulsive events. It was dissimilar from the one we have looked at principally in that its timespan was less than 5 seconds. It occurred about a minute later than the period of impulses in question. We found no other impulsive patterns on the tape.
3) The impulses shown on the audiograph are not gunshots but random impulses created by ambient noise;
4) The dictabelt recording can not be matched to the Zapruder film because it has been altered;
5) The four to six shots recorded by the dictabelt contradict the Warren Commission's findings therefore it can not possibly be true;
5. Yes, believe it or not, some people make that argument.
Speaking of the WC, we now know that the commission had an analysis done on a KBOX radio station recording that was made in Dealey Plaza during the assassination. The analysis was done by acoustical expert Larry Kersta at the Bell Telephone Lab in New Jersey. Kersta only had the equipment to do a spectrographic analysis of the tape, but he found that it contained six "non-voiced" noises! Moreover, the KBOX "non-voiced" noises follow the same sequence and pattern as do the six dictabelt impulses that passed the first BBN screening for gunfire: the first one is different from the others, followed by three impulses close together, followed by a slight pause, followed by two more impulses similar to the previous three. My, my, my, what an amazing coincidence.
6) Some gunshot impulses on the recording can not be matched to any test shots, therefore the acoustic evidence is invalid.
A correlation of 0.8 may be very low if one is verifying a physical law using high-quality instruments, but may be regarded as very high in the social sciences, where there may be a greater contribution from complicating factors.
Now that’s what I call experts. :)
What kind of an expert would make calculations that are off by more than 3 orders of magnitude? They calculated the odds as 1 and 20, but with the correct calculations the odds are 1 in 100,000. I don’t believe in Dr. Thomas’s one in 100,000 odds any more than I believe in the 1978 HSCA acoustic experts 1 in 20 odds.
Not when the positions of the motorcycles make the odds zero.
There are compelling arguments for the stuck open mic being at the Trade Mart, not at the Plaza, like
Worth a read: https://www.jfk-online.com/bowles7.html#N_74_
Otto has a good point. I wish Mr. Griffith would drop everything else and deal with this issue:
https://www.jfk-online.com/bowles7.html#N_74_ (https://www.jfk-online.com/bowles7.html#N_74_)
Let’s go over the timeline of the 5.5-minute period when the microphone was stuck:
12:31:13 Impulse from what BBN claimed was made by the last shot in Dealey Plaza.
12:31:56 Someone whistling a tune in the background
12:32:42 Someone whistling again.
12:33:01 Sound of sirens can be heard, faintly, but increasing in loudness.
12:33:03 Sire sounds continue.
12:33:18 Sire sounds continue.
12:33:26 Sire sounds continue.
12:33:34 Sire sounds continue.
12:33:55 Someone whistling again.
12:33:38 DSO? Attention all units, all units . . .
12:34:19 Microphone closed.
So, this is recorded either by a motorcycle, initially escorting the motorcade, then escorting the limousine to Parkland hospital. The Trade Mart Center was two miles from Dealey Plaza, but just 200 yards from Harry Hines Blvd. along which the limousine with escorting motorcycles with sirens blaring passed by.
There are several things that clearly indicate that the motorcycle with the stuck microphone was at the Trade Mart Center and not with the motorcade in Dealey Plaza during the shooting.
1. The sound of the sirens does not come on suddenly and loud and stay loud for five minutes. Instead, there is the sound of no sirens. Then distance sirens. Then the sirens gradually get louder, stay loud for several seconds, then gradually fade away.
2. After the shooting, while, supposedly being recorded by a motorcycle speeding on the freeway to Parkland, we often hear no sirens but the sound of whistling.
3. The crosstalk “Attention all units, all units . . .”, the sound of a Dispatcher alerting all units. But this could not have been the Dallas Police Dispatcher, since nothing like this was recorded on Channel 2. It could only have been a dispatcher with another organization, like the County Sheriff Department. And none of there vehicles were escorting the motorcade but some of them where at the Trade Mart Center.
Question for Michael Griffith:
On each of these three points, can you, just using what is recorded on the Dictabelt, explain how this fits a motorcycle escorting the limousine to Parkland Hospital better than a motorcycle waiting at the Trade Mart Center?
Just stick to what’s on the tape and just address these points. Yes, I know when the evidence goes against them, CTers cherry pick some witness. Like the Police Dispatcher who broadcast:
“Unknown motorcycle - up on Stemmons with his mike stuck open on Channel 1. Could you send someone up there to tell him to shut it off?
which is ambiguous anyway because the Trade Mart Center is right by the Stemmons freeway.
Joffrey. There was a motorcycle with a stuck ‘transmit’ button, but it was not with the motorcade. It was at the Trade Mart.
Joffrey, the KBOX recording was a recreation. They did NOT record the assassination as it happened.
The sirens are a problem?! The motorcycle was at the Trade Mart?! Seriously? Yes, I know that's what the pro-WC websites you rely on tell you, but the sirens and the Trade Mart claims were debunked years ago. If the gunfire impulse patterns were not recorded in Dealey Plaza, then, Laurel and Hardy, you two finally, finally, finally need to get around to explaining how echo patterns unique to Dealey Plaza are contained in the dictabelt's gunshot impulse patterns, and how the N-waves, muzzle blasts, and muzzle-blast echoes of those gunshot impulse patterns were recorded in the correct order and interval on the dictabelt.
There you go again, stating an assumption as a fact.
That's false. They were live broadcasting during the motorcade and turned their original recordings over to the WC. They were "unavailable" when it came time to do the "The Four Days that Shocked the World" record album, so they had Sam Pate record the re-creation. The original tapes were still "missing" in 1978 when the HSCA tried to find them.
Show us a link to an audio recording for the entire 5.5-minute span of the stuck microphone. And let the members here judge for themselves if the sirens sound like they are constantly blaring during the second half of the recording, or if it does sound like sirens that approach from the distance, get close, then receded away.
Where are the links to the articles that show:
1. KBOX – was making a broadcast from the motorcade at the time of the shooting.
2. A recording (not a recreation) was made of this broadcast.
3. And that this recording (again, not a recreation) was turned over to the Warren Commission.
Where are the links to the articles that show:
1. KBOX – was making a broadcast from the motorcade at the time of the shooting.
2. A recording (not a recreation) was made of this broadcast.
3. And that this recording (again, not a recreation) was turned over to the Warren Commission.
Both Sam Pate and Karl King acknowledged this in comments made here:
http://www.reelradio.com/comment/comment.cgi?kbox112263~KBOX+Dallas,+November+22,+1963~../se/index.html (http://www.reelradio.com/comment/comment.cgi?kbox112263~KBOX+Dallas,+November+22,+1963~../se/index.html)
I was on the news desk at KBOX and at the half hour, I read a 30 second news break, and returned the air to the disk jocky. Sam came on the two way and very excitedly hollared "Karl, put me on, the police parade frequency is sayiing shots have been fired at the motorcade."
I signlaed the dj to kill the record he was playing and got on the air to introduce Sam with his report of shots being fired at the Presidents motorcade. I started the newsroom tape.
Jenkins says he was in another mobile unit waiting for the motorcade to go through Dealey Plaza when a police buddy in front of him pulled back and yelled at him through the window.
“‘They got a problem up there somewhere,’” Jenkins said the police officer told him. “Shots had been fired. I said ‘What do you mean?’ [The officer] said someone had fired shots at the motorcade.”
I was on Stemmons Fwy when the radio and Sheriff Bill Decker said to get some men up into those railroad yards and find out where those shots came from. I immediately radioed Karl King that shots have been fired, put a bulletin on immediately. Karl did and then called UPI and according to UPI, we had beaten their own guy Merriman Smith to the story. There were no cell phones back then, tv cameramen didn't have audios. I was in the Northbound Lane faceing the southbound lanes and I was talking to a guy names Josh Dowdell who had pulled up behind me to see if I had car trouble. I told Josh, a friend of mine , to get in and wait for the motorcade..that was when Deckers report came on. After I radioed King, I peeled rubber toward the motorcade and when we met all of us were going about 80 miles per hour and I was heading right for them. I was afraid to veer oneway or another because they might also veer from their lane. Kennedy's car went right by my drivers side, the dark blue cadillac convertible went to my right and Johnson's light blue lincoln went far to my left and almost went off the freeway.
Wait a minute. You are the one who described this "sirens that approach from the distance, get close, then receded away". You haven't actually heard the recording?
Yes. I have heard the recording. John McAdams provides it, along with the transcript.
The sirens are a problem?! The motorcycle was at the Trade Mart?! Seriously? Yes, I know that's what the pro-WC websites you rely on tell you, but the sirens and the Trade Mart claims were debunked years ago. If the gunfire impulse patterns were not recorded in Dealey Plaza, then, Laurel and Hardy, you two finally, finally, finally need to get around to explaining how echo patterns unique to Dealey Plaza are contained in the dictabelt's gunshot impulse patterns, and how the N-waves, muzzle blasts, and muzzle-blast echoes of those gunshot impulse patterns were recorded in the correct order and interval on the dictabelt.