Question about Dr. Donald Thomas’s Dictabelt Offset Hypothesis

[Joe Elliott]

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:
 

The bottom line, despite all the claims you make, despite all the claims the Acoustic experts from the 1978 HSCA study make, despite all the claims Dr. Thomas make, we don’t know what gunshots on a Dictabelt would sound like. We have all sorts of unanswered questions.

•   Would Dictabelt record the sounds of gunshots as N-waves we see on the 1963 Dictabelt recording?
•   Would the Dictabelt record the sounds of gunshots as sounding something like the sound of gunshots, or at least as audible noises, or would it be like the 1963 recording?
•   Can the recording of Channel 1 be offset in time from Channel 2, so that crosstalk could make it appear that events happened a minute apart, even thought they really happened at about the same time?

We don’t know the answer to these questions, and we will never know the answer to these questions because the 1978 Acoustic experts failed to test this out.

So, all we have, is the assurance of these Acoustic experts is that:

•   Yes, the Dictabelt would record the sounds of gunshots, just like the N-waves recorded on the 1963 recording.
•   No, the sound of the gunshots won’t sound like gunshots, or even as loud noises, on a Dictabelt recording.
•   Yes, the sounds recorded can be offset, so the “sound of the gunshots” could appear to happen at the same time as a recorded phrase like “Hold everything secure”, even if they really happened a minute or more apart.

In an ideal world, we would not only have the opinion of these experts, but we would have proof of their claims, in a 1978 Dictabelt recording. Real competent scientists, don’t just give us their expert opinions. They also provide proof when possible. And the test which would have proven, or refuted, some or all of these claims were not run in 1978, even though they could easily have been run. And this failure was caused by these same acoustic experts you ask us to trust.

Question:

How much stronger would the acoustic expert’s claims be if we had:

•   A 1978 Dictabelt recording which recorded gunshots as N-waves quite similar to the 1963 recording.
•   A 1978 Dictabelt recording which recorded gunshots as inaudible sounds, just like the 1963 recording.
•   That demonstrated, the sounds recorded, via crosstalk, could appear to happen at about the same time, but really have occurred about a minute apart.

Answer:

Immensely stronger. Immensely stronger. And disproven If the 1978 Dictabelt recording did not demonstrate this.

Does anyone disagree with my answer?



The bottom line is you and others can claim all day about, what a Dictabelt recording would show, what it would not show, but no one really knows. Because this was not tested out in the real world. And we know how to blame. The acoustic experts who screwed this up back in 1978.

[Joe Elliott]

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.

I am going to get a little off topic here. I can assure you that Mr. Blenner does not know his stuff.

He once objected to the following testimony of Larry Sturdivan

Mr. STURDIVAN.
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.

What was Mr. Blenner’s objection. That 18.4 pound feet per second is not the correct answer, and that it is not even an expression of momentum.

I asked, “What to you mean “pound per second” are not units of momentum. Momentum is expressed as “mass * velocity” or “mass * distance / time”. He responded with a quote from a government report showing momentum being expressed in “pound seconds”, not “pound feet per second”. So “pound feet per second” are not units of momentum. So, Larry Sturdivan did not know basic physics.

Now I confess, I was a little confused about this at first. I only took Physics in high school. And a quarter in college. I had never heard of momentum being expressed in “pound seconds”. But, when I thought about it for a bit, I realized that both made sense. If the “pound” in “pound feet per second” is a unit of mass, then this is a valid unit of momentum. And if “pound” in “pound seconds” is a unit of force, then this is also a valid unit of momentum. But I never presented myself as anything other than a former good high school physics student. Herbert Blenner gives the impression that he is much more than that. But he failed to see how “pound feet per second” is a valid unit for momentum. Like he didn’t understand that momentum is mass times velocity. I don’t think that Herbert Blenner knows as much about physics as I do.

By the way, why was Larry Sturdivan not using the metric system, as any good scientist should do? Because he was giving testimony to laymen and was told to use English units, not Metric units, so they would not be confused.


This conversation was recorded on this forum, but it all disappeared a few years ago when the forum went down due to a hacker attack.

[Michael T. Griffith]

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/

[Joffrey van de Wiel]

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!

[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