Question about Dr. Donald Thomas’s Dictabelt Offset Hypothesis

[Gerry Down]

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;

This is what gets me. Shouldn't a person be able to hear shots on the dictabelt recording?

[Michael T. Griffith]

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.

Let me answer these by their number.

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. This is a summary claim that I think is totally refuted by the evidence. For example, there are N-waves from supersonic rifle fire on the dictabelt on the shots that were recorded when the microphone was in a position to record N-waves, and the grassy knoll shot's N-wave comes 24 milliseconds before its trailing muzzle blast, just as it should. N-waves from rifle fire typically come 10-30 milliseconds before the muzzle blast behind them. 

3. This is another summary claim that I think is also totally refuted by the evidence. The correlations between the dictabelt gunfire impulse patterns and the test-firing impulse patterns are powerful, compelling evidence that the dictabelt contains recorded assassination gunfire.

4. Yet, there are definite correlations between the dictabelt gunshots and gunfire reactions in the Zapruder film, somewhat to my surprise. It is entirely possible that the Zapruder film was not altered enough to prevent it from correlating with the dictabelt. Much of the alteration involved adding, removing, and doctoring images on the film, which would not affect correlation with the dictabelt. Also, since the dictabelt might not have recorded one of the shots fired at JFK, because of how the shot was fired and because of the DPD dispatch system's AGC circuitry, it just might be that this unrecorded shot is part of the reason that the dictabelt does correlate rather well with the Zapruder film.

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. I don't know who said that, but they must not have read any of the HSCA materials. Only five of the impulse patterns met all of the BBN screening criteria for gunfire, and all five of those impulse patterns match shots from the Dealey Plaza test firing. I might add that no other impulse pattern anywhere on the 5.5-minute dictabelt segment met all the BBN criteria for gunfire.

[John Iacoletti]

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.

Which, by the way, is one of the many original pieces of evidence that "can't be located".  The common recording we've all heard ("it appears something has happened in the motorcade route") is a re-creation.

[Joe Elliott]

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.

No. You provided a bunch of links without saying which link has the information I requested. Otto, in contrast, gave me just one link, that was just a few pages long, that provided the information.

You provided no link to (until after Otto did):

http://www.whokilledjfk.net/hear_no_evil.htm

Or any other similar website where the information is right there.


You don’t have to find such a website. It would have been as simple just type out:

The BBN found shots at z175 (TSBD), z204 (TSBD), z312 (Knoll) and z326 (TSBD). And Dr. Thomas found a fifth at z224 (TSBD).


I think that you wanted to keep it a secret, at least from the casual views, of a first shot at z175, which really make it difficult for Officer McLain to be there for the first shot.

[Joe Elliott]

The points of contention are:

Actually, I’m am certain we have only seen a portion of the tip of the iceberg so far.

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.

Joffrey. There was a motorcycle with a stuck ‘transmit’ button, but it was not with the motorcade. It was at the Trade Mart.

I see you watched the 40-minute video by Dr. Thomas. In it, he seems to make an overwhelming case that the motorcycle with the stuck microphone was with the motorcade, because he played an 8-second clip of the sounds of loud sirens, exactly the sort of thing that would be recorded by a motorcycle going with the President to the hospital.

However, if one does not “cherry pick”, as Dr. Thomas did, which section of the tape to play, but played the whole thing for the 5 minute trip to the hospital, you would have heard:

Very little
Sirens approaching from the distance, then getting louder, then quite loud for a few seconds, then get less loud and receding the distance.
And again, the same patter with the sirens, getting loud and receding.
And again, the same patter with the sirens for the third time, getting loud and receding.

This is not consistent with a motorcycle travelling with its sirens on to the hospital for the full 5 minutes. This is consistent with a motorcycle waiting at the Trade Mart Center for the President, and hearing the sirens as they passed right by on the freeway. The Trade Mart center was very close to where the limousine was as it rushed to the hospital.

I claim, it was dishonest for Dr. Thomas to play just a short clip. I am very confident that Mr. Griffith will not make available to you a recording of this entire 5-minute span, no more than Dr. Thomas did.

2) The open microphone did not record any gunshots;

Since the motorcycle appears not to have been with the motorcade, it could not have recorded the gunshots.

But one thing that is beyond dispute, is that many of these “sound impulses” were not gunshots.

Below is a quote from Dr. Barger with the BBN, who gave testimony to the HSCA in 1978 in support of the acoustic data.

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.

So, about a minute after the alleged gunshots, there was another of multiple sound impulses. No one is saying there was several seconds of gunshots, followed by a minute of quiet, followed by another flurry of gunshots.

Also, of the 7 sound impulses that were recorded at the time of the alleged gunshots, 4 sound impulses were accepted as gunshots, 3 were rejected by the BBN. Years later, Dr. Thomas said one of these was a real gunshot. And it just happens to corresponds to z224 so I suspect Dr. Thomas wanted at least two of the gunshots at z224 and z313, to match the Zapruder film better.

Now, who knows, I don’t know the absolute truth. But one thing I can say for certain. Most of the sound impulses on that tape were not caused by gunshots. And likely none of them were.

3) The impulses shown on the audiograph are not gunshots but random impulses created by ambient noise;

I don’t know the technical reason. I heard the vibration of the engine could caused these sound impulses, these “N-waves”. I don’t think anyone knows for certain. But there are too many of them and too much spread over time for them to all have been gunshots.

4) The dictabelt recording can not be matched to the Zapruder film because it has been altered;

Actually, if one accepts that Dr. Thomas shot at ‘140.32 seconds”, that matches up well with the BBN shot at ‘145.15 seconds” A gap of 4.83 seconds which is within a tenth of a second of the gap between z224 and z312, when many people, including me, say two shots did occur. Well, that’s pretty amazing, isn’t it. I mean the odds of that are something like one in a hundred of that happening, correct?

No. Remember there were 7 sound impulses within a few seconds of each other. Mathematics says that there are 7*6/2 or 21 possible unique pairs. “Shots 1 and 2”, “Shots 1 and 3”, etc. So, the real odds are not 1 in 100 but more like 1 in 5.

And maybe somewhat less, because there was another cluster of “shots” a minute afterwards that the BBN could have focused on. They made have focused on the one they chose because they knew about this 4.83 second gap between two of the sound impulses in the first cluster.

This is similar to the problem where a teacher, year after year, finds that often, two of his students in his class have the same birthday. With 22 students, there are 22*21/2 or 231 unique pairs. More than half of 365. So, it is not a vast coincidence for him to discover such pairing in many years.

5) The four to six shots recorded by the dictabelt contradict the Warren Commission's findings therefore it can not possibly be true;

Yes, it would.

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.

Joffrey, the KBOX recording was a recreation. They did NOT record the assassination as it happened.

It was similar to the 1938 Orson Wells broadcast of the “War of the Worlds”, where they didn’t record a real invasion of the Earth from Mars, but a fake one.

At the end of the day, I admit, it is conceivable that the Dictabelt did have a recording of the assassination, despite all the evidence against it. But there is no way this KBOX recreation from a latter day recorded the gunshots at Dealey Plaza.

6) Some gunshot impulses on the recording can not be matched to any test shots, therefore the acoustic evidence is invalid.

No. If most did not match at all, but a few matched very very well, that would be of much interest. Now before we go on, I should say that I am very good at mathematics. At algebra, calculus, trigonometry, at least when I have been practicing. But not so good at statistics. So, take what I say with a grain of salt.

Correlations between two data sets can be measured, like between the data from 1963 and the data from a 1978 test, to get something called a “Correlation Coefficient”. This coefficient must always be between -1 and +1. If outside that range, an error in calculation has occurred. A correlation of +1 is very good. A perfect match of data. A correlation of -1 is very bad, because you always get the opposite results. Actually, this might be good because if a bad model predicted one result, you would know the opposite would always actually happen. And a correlation of 0, means the comparisons are random. Occasionally a match is found, but this is just by luck.

https://en.wikipedia.org/wiki/Pearson_correlation_coefficient

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.

The BBN tested, believe it or not, over 2,600 hundred tests. 78 gunshots, recorded at 36 microphones. I make it out to be 2,808 tests. Of these 15 had a correlation coefficient of 0.6 or greater. And 4 were found with a correlation coefficient of 0.8, which caused the BBN to conclude that these were shots. I should think one should find some correlations with 2,808 possibilities.

Now, to a layman like me, this seems questionable, since 0.8 provides a low degree of confidence. Although it could be asked “Is the Dictabelt recording a “high-quality” instrument?” I would guess not.

Still checking 2,808 results and finding 4 somewhat weak correlations, of only 0.8, does not sound impressive to me. But when it comes to statistics, I am well out of my depth.

[Michael T. Griffith]

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.

Oh! Okay! So I take it you say the same thing about the numerous egregious errors in the NRC panel's report, right? Right? Right? Yeah, uh-huh. No, you won't, because you don't deal with the evidence honestly or objectively.

The HSCA experts used the wrong value for one of the values that went into their calculations of the odds. The calculations themselves were done correctly, but they were off because of the errant value that was used. And, as mentioned, if they had used not used the incorrect value, they would have discovered that the odds that the correlations were coincidence were far more remote than they calculated. With the errant value, they calculated the odds of the correlations being coincidence as less than 1 in 20, or less than 5%, when in actuality the odds are 1 in 100,000.

Not when the positions of the motorcycles make the odds zero.

More of your amateurish jibberish. Are you ever, ever, ever going to deal with Dr. Thomas's section on the position of McClain's motorcycle in his book Hear No Evil?

[Joe Elliott]

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_

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.