Question about Dr. Donald Thomas’s Dictabelt Offset Hypothesis

[Michael T. Griffith]

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).

[Joe Elliott]

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).

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.

See:

Dictabelt Acoustic Question – Who Rode the Motorcycle

https://www.jfkassassinationforum.com/index.php/topic,2710.0.html

[Joe Elliott]

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!

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.

The best I can figure, the original HSCA acoustic experts back in 1979 reported that the timing of the shots are:

First shot, Time 0.0 seconds, from sixth floor or the TSBD. Motorcycle is approaching Elm Street, must be within about 12 feet of Elm Street (my estimate), if going 5 MPH around the sharp corner.
Second shot, Time 1.6 seconds, from sixth floor of the TSBD. Motorcycle was at the corner of Houston and Elm.
Third shot, Time 7.6 seconds, from Grassy Knoll. Motorcycle was 80 feet west of Houston and Elm.
Fourth shot, Time 8.2 seconds, from sixth floor of the TSBD. Motorcycle was about 90 feet west of Houston and Elm.

To see how I got these numbers, you can see my initial post at:

Dictabelt Acoustic Question – Who Rode the Motorcycle

https://www.jfkassassinationforum.com/index.php/topic,2710.0.html

You say you have trouble interpreting written information because English is your second language? Believe me, even for someone like myself who only knows English, interpreting the HSCA Acoustic expert statements on when the fourth shot was fired is not easy. But as near as I can tell, they claim the fourth shot was fired 8.2 seconds after the first.

I don’t know, but I suspect, the Acoustic expects made this language confusing on purpose, to make it less clear as to what frames of the Zapruder film each shot corresponded to. Because they knew there was no good correspondence between the Zapruder film and their conclusions as to when the “shots” were fired.

*** Change ***
From the following chart:
https://books.google.com/books?id=lCDVdv11Q1MC&pg=PA63&lpg=PA63&dq=%22beginning+time+of+first+impulse+on+tape+segment%22&source=bl&ots=3uXAAkZjGt&sig=ACfU3U1rzIrEAgyIU-rPg5-9KT6bi82XtQ&hl=en&sa=X&ved=2ahUKEwj2x6_G6-vrAhXMs54KHbSxCYIQ6AEwAHoECAEQAQ#v=onepage&q=%22beginning%20time%20of%20first%20impulse%20on%20tape%20segment%22&f=false

I got, what I assume, are more accurate numbers than listed in the January 1979 Acoustic Report. The numbers are hard to make out, but I get:

First shot, Time 0.00, from the TSBD.
Second shot, Time 1.57, from the TSBD.
Third shot, Time 7.45, from the Grassy Knoll.
Fourth shot, Time 7.91, from the TSBD.

So I have modified my post slightly to go with these numbers.

*** ***


So, if the third shot corresponds to Frame 313, the timing is:

First shot, Zapruder frame 177, from the TSBD.
Second shot, Zapruder frame 205, from the TSBD.
Third shot, Zapruder frame 313, from the Grassy Knoll.
Fourth shot, Zapruder frame 321, from the TSBD.

This doesn’t make any sense. When were Kennedy and Connally wounded? At 177? At 205? At both? I guess the Acoustic experts have no problem with both shots from the TSBD at frame 177 and 205 having to pass through the leaves of a tree. Why not? The HSCA had no problem with one bullet doing so, so why not two?



Let’s try the fourth shot corresponds to Frame 313. If so, the timing is:

First shot, Zapruder frame 168, from the TSBD.
Second shot, Zapruder frame 197, from the TSBD.
Third shot, Zapruder frame 305, from the Grassy Knoll.
Fourth shot, Zapruder frame 313, from the TSBD.

This doesn’t make any sense either. When were Kennedy and Connally wounded? At 168? At 197? At both? Again we have two bullet from the TSBD going through a true. Also, if this scenario is accepted, forget about “Back and to the Left”. Because this means the fatal shot at Zapruder frame 313 did come from behind, from the TSBD, just as the Warren Commission supporters have said all along.


And, of course, it makes even less sense for the first or second shot to be at frame 313.

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.

The correlation between the timing of the “gunshots” on the Dictabelt recording matches up well with the Zapruder film, does it? Well let’s see you demonstrate this to Joffrey.


Questions:

1.   How many gunshots were fired all together? The Acoustic experts and their supporters, like yourself, seem vague on this basic question. Was it 4, 5 6, or more than 6? What is the answer?

2.   What is the timing of the shots? First shot at Time 0.0 seconds, Second shot at Time 1.6 seconds, etc.

3.   Where was each of these shots fired from? First shot from the TSBD? Second shot from the TSBD, etc.

4.   Which frames do each of these shots correspond to on the Zapruder film? If it’s hard to answer definitively, because you don’t know if it was the third fourth or fifth shot that corresponded to frame 313, list out the possibilities, like I have done.


Joffrey can correct me if I am wrong, but I think he would like to see these questions answered as well as I. And not get some sort of evasion.

[Michael T. Griffith]

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]

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?

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.

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.

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?

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

[Joe Elliott]

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

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.

[Joe Elliott]

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.

Question:

Are you claiming that 1 to 2 seconds, or 18 to 36 frames, were removed from the Zapruder film?

Is so, what did they replace these missing frames with?

[Joe Elliott]

The failure of the acoustic analysis, is best shown by the failure to specify when the shots occurred relative to each other.

Back in January 1979, the acoustic experts published the intervals.

First shot at time 0.00 seconds, from the TSBD.
Second shot at time 1.57 seconds, from the TSBD.
Third shot at time 7.45 seconds, from the Grassy Knoll.
Fourth shot at time 7.91 seconds, from the TSBD.

These times are relative to the first shot. So, the 4 shots were over an interval of 7.91 seconds.

They have not published such a table since. Why?

Because the times don’t correlate to the Zapruder, Hughes and Nix films.

The Zapruder and Hughes film, while they don’t show when Officer McLain is at frame z223, they show him too far away to reach within 15 feet of Elm Street, where they need him to be where the acoustic data says he must be. Even if they choose the latest possible time, z223, it doesn’t work. A second difficulty is that if the first shot is at z223, the second shot is at z 252, too soon for the head shot, and the third shot is at z359, way too late to be the head shot.

Pushing the first shot back to z177 solves this problem, but it makes the McClain problem even more absurd, requiring him to travel 200 feet in one second. Impossible. And also, impossible, I might add, in 3.4 seconds.

The Nix film is a problem because it shows all four of the officers who are supposed to be right behind, the Presidential limousine at the time of the head shot, when one of them is supposed to be 120 to 160 feet behind. And the Hughes film shows Officers McLain and Baker right where they are supposed to be, 350 feet behind the Presidential limousine, between vehicles 10 and 11 (the Presidential limousine is vehicle 2) as late as Zapruder frame 160, still going at a slow steady speed. Both the Zapruder film and the Hughes film show the Vice-Presidential car just starting to turn onto Elm, establishing where Officer’s McLain and Baker are at Zapruder frame 160.

That’s it. They are all out of motorcycle officers who could be at Houston and Elm in time. No one is close to where the acoustic evidence says one motorcycle should be, 120 to 160 feet behind the President. Far from making an excellent prediction, the acoustic experts made about the worst prediction they could have made. Not 0 to 40 feet behind the President. Not 330 to 370 feet behind the President. But right in the black hole. Right where there are no police motorcycles with a radio transmitter.


Hence, for the last 40 years, no published list of the time intervals of the Dictabelt shots. An assurance that the time intervals match what is shown on the Zapruder film to an amazing degree, which is an amazing claim, considering that Mr. Griffith does not seem to know what these time intervals are. At least he is not telling us.

Dr. Thomas has since discovered a “fifth shot” somehow missed by the acoustic experts. I think the main value, is that maybe this fifth shot could partly fix the problem. Maybe it will allow a late first shot while still allowing a shot to occur at frame 313. But I don’t think so, because if it did, Dr. Thomas would publish the time intervals of the five shots and not keep them a secret.

Hence, the need to keep these time intervals between the shots a big mystery.

If this is not enough to convince people that the acoustic claims are bogus, I don’t know what is.


Now, expect Mr. Griffith to explain how ignorant I am and to post a link to a bunch of other materials, and to recommend a book or two for people to purchase, and to recommend of us to check it out. None of which will provide these time intervals between the acoustic “shots”.