HSCA 1978 Acoustic Study by BBN – Figure 367

[Joe Elliott]

I'm currently looking at Fig 22 on page 63 where "false alarms" are marked with an X,

https://www.history-matters.com/archive/jfk/hsca/reportvols/vol8/html/HSCA_Vol8_0054a.htm

If you read on it's a simple fact they have have false alarms and they document them as they should.

In line with the fingerprint analogy proposed by Barger, for each acoustical fingerprint, they're now left them with several suspects, some of which are in fact false suspects. As I understand the explanations even more would have been acceptable and it's to some degree (lost reference) due to the spacing of the microphones. The further apart the worse the quality of detection becomes.

A pretty crazy example is #1, on top of page 65, at 137.70.

Even though the tape has already been screened and filtered they need to do further cleansing using additional "logic".

By the way (Otto can correct me if I am wrong) “Page 65” refers to the small “65” at the bottom of the page. One the same page, number “105” is on the top with a larger font. And for the blue index number along the top, clink on 107 to get to page 105/65.

Well, Mr. Griffith seems pretty reluctant to admitting all the “False Positives” in their data, but as you have noted, Dr. Barger is upfront and honest about them.

I like how they just blithely dismiss false positive after false positive.

Yes, we must dismiss the fourth entry for 139.27. And yes, we must dismiss the third entry for 139.27. But we won’t dismiss the first entry because that would destroy all our evidence for any gunshot at 139.27.

Or:

Yes, we must dismiss the fourth entry for 139.27 because that would indicate 130 feet in 1.6 seconds to gain that position. While there at it, why don’t they dismiss all the entries because the motorcycle would have to travel 164 feet in 1.5 seconds from the time the Hughes film is turned off to reach position 2 ( 5 ).

In the following, my phrases are in [[double brackets]].

However, the expected number of false alarms [[false positives]] to be found when testing four different impulses patters is 13 (see Appendix C), and only six [[false positives]] have been found. Therefore, it is not unreasonable to expect that there are seven more [[false positives]], although that would be the largest number possible since at least two of the remaining nigh are probable detections [[true positives]].

Ok. We found 6 false positives. We suspect there are more, maybe 7 more false positives, but we can’t tell which ones they are. But it can’t be as many as 11 more false positives because that would cause our case to go up in smoke.

[John Iacoletti]

https://mcadams.posc.mu.edu/dpdtapes/

It is a 2:41 (two minutes, forty one seconds) recording at around 12:30.

Click on the little “speaker” and it may say you need to download Realplayer, which I did. It was fairly straight forward. I would prefer it was on youtube.

But yes, around 1:20 into the 2:41 recording, the sirens start up, build up and fade away by 1:57. I hear no more sirens from then on and the recording goes about another 44 seconds.

Thanks.  Here's the direct link to the audio file for anybody else who might be interested.

https://mcadams.posc.mu.edu/dpdtapes/capture24.ram

I definitely hear the sirens.  Whether they "gradually get louder, and then fade away, as if recorded from a stationary motorcycle at the Trade Mart Center" seems to be a bit of an interpretive stretch.

[Joe Elliott]

Thanks.  Here's the direct link to the audio file for anybody else who might be interested.

https://mcadams.posc.mu.edu/dpdtapes/capture24.ram

I definitely hear the sirens.  Whether they "gradually get louder, and then fade away, as if recorded from a stationary motorcycle at the Trade Mart Center" seems to be a bit of an interpretive stretch.

I don’t think it is much of a stretch. But would be an incredible stretch to say this was recorded from a motorcycle accompanying the limousine to the Parkland hospital, but only recorded 36 seconds of sirens. We know McLain escorted the limousine to Parkland, because he said in an interview:

https://www.kenrahn.com/JFK/History/The_deed/Sneed/McLain.html

In any case, I caught up with and got in front of the limousine on Stemmons somewhere around Continental. The ride was wild! You know in your mind that you’re going way too fast, but if you slow down or fall, the cars behind are going to run over you. But you don’t think about those things, though, at the time; it’s all instinct.

We had to slow down when we got off Stemmons at Industrial. Along Industrial there was a railroad track which was located on a small incline some twenty to thirty feet before we were to hit Harry Hines Boulevard. Chaney, myself and another officer went airborne up the incline, hit the ground, and made the sharp left onto Hines.

When we arrived at the hospital, I parked my motorcycle and came back to the limousine about fifteen feet away. As the hospital orderlies approached to take him out of the car, Mrs. Kennedy was still laying over him, covering his head, and wouldn’t get up. So, I took it upon myself, reached over and caught her by the shoulder, pulled her and said, “Come on, let them take him out.” Somebody threw a coat over him just as she raised up, and they took him out on the right side of the car. She then stepped out on the left, stunned, and walked with me in a daze into the emergency room.

Looking at Google maps, catching up with the limousine around Continental meant that Officer McLain caught up with the motorcade within the first mile. Continental Avenue runs east and west, just north of the current 366 freeway. By the way, the name of Industrial Blvd has since been changed to Riverfront Blvd. (southern section) and Market Center Blvd. (northern section).

So, Officer McLain must have left Dealey Plaza immediately after the limousine left, caught up to it just north of 366 and the motorcade exited the Stemmons freeway at Market Center Blvd. (formerly Industrial Blvd.) and continued on to the hospital. And we know he went directly to Parkland because he was there to help Mrs. Kennedy out of the limousine. Clearly, we should be hearing the sirens for more than 36 seconds if he was escorting the limousine 80% of the way to Parkland.

The microphone being on a motorcycle at the Trade Mart Center is not too much of a stretch:

•   It is known that police motorcycles were waiting at the Trade Mart Center.
•   The limousine passed within 200 yards of the Trade Mart Center.
•   The phrase “Attention all units” heard on the Dictabelt was not broadcast by the Dallas police dispatcher, because it is not recorded on Channel 2. But it could have been the Dallas county sheriff dispatcher, and none of their vehicles were escorting the motorcade but some were waiting at the Trade Mart Center.
•   The sound of someone whistling does not fit with a motorcycle speeding off the Parkland, but does fit a motorcycle waiting at the Trade Mart Center.

[John Iacoletti]

•   It is known that police motorcycles were waiting at the Trade Mart Center.
•   The limousine passed within 200 yards of the Trade Mart Center.
•   The phrase “Attention all units” heard on the Dictabelt was not broadcast by the Dallas police dispatcher, because it is not recorded on Channel 2. But it could have been the Dallas county sheriff dispatcher, and none of their vehicles were escorting the motorcade but some were waiting at the Trade Mart Center.
•   The sound of someone whistling does not fit with a motorcycle speeding off the Parkland, but does fit a motorcycle waiting at the Trade Mart Center.

Where do you hear the phrase "attention all units"?

Where do you hear "the sound of someone whistling"?

How does whistling indicate Trade Mart anyway?

How do you know the 2:41 excerpt was continuously recorded and is complete?  I hear "clear 12:34" twice in the excerpt.  Once at 2:23 and then again softer at about 2:32.

[Joe Elliott]

My answers to the following questions are based on the recording of the motorcycle with the stuck button using Channel 1, which was stuck for 5 and a half minutes. The link below plays the last 2:41 of this period.

https://mcadams.posc.mu.edu/dpdtapes/capture24.ram

Where do you hear the phrase "attention all units"?

This is very difficult to hear. Like the phrase “Hold everything secure”. But I here some brief phrase of “. . . all . . .” right at 2:00. But, admittedly, this is very difficult to make out.

Where do you hear "the sound of someone whistling"?

In several parts, but most clearly at 1:02, just after someone says “1 2 3 4”. It only lasts a couple of seconds, but is clearly a brief tune, not just a tone of some sort.

How does whistling indicate Trade Mart anyway?

It is a very strong indicator of a motorcycle not with the motorcade, not escorting the Presidential limousine at high speed to the Parkland Hospital.

If is a fairly strong indicator of a motorcycle at the Trade Mart Center because:
•   It was known that several motorcycles were waiting at the Trade Mart Center.
•   One can hear the sirens pass by the motorcycle making this recording and the Presidential limousine with the escorting motorcycles passed within 200 yards of the Trade Mart Center.
•   An officer not actively escorting the President but waiting for him to arrive, might, in the few idle minutes left to him, and knowing nothing of the shooting, start to whistle.

But the bottom line, the whistling being recorded is wildly unlikely for Officer McLain’s motorcycle, just from the whistling alone.

How do you know the 2:41 excerpt was continuously recorded and is complete?  I hear "clear 12:34" twice in the excerpt.  Once at 2:23 and then again softer at about 2:32.

Because as long as the microphone button is stuck, it will keep recording continuously. It only stops recording if no one is transmitting anything. The phrase “clear 12:34” might be repeated twice in 9 seconds, in case the officer didn’t think his first message got through.

[John Iacoletti]

This is very difficult to hear. Like the phrase “Hold everything secure”. But I here some brief phrase of “. . . all . . .” right at 2:00. But, admittedly, this is very difficult to make out.

So you don’t actually hear the phrase “attention all units”? Did somebody else claim that phrase was on the recording?

In several parts, but most clearly at 1:02, just after someone says “1 2 3 4”. It only lasts a couple of seconds, but is clearly a brief tune, not just a tone of some sort.

Not clearly a tune or even a human to me, but ok.

It is a very strong indicator of a motorcycle not with the motorcade, not escorting the Presidential limousine at high speed to the Parkland Hospital.

So basically when you stated (as a fact) that  it was specifically at the Trade Mart, that was just an assumption, right? Your argument is really just that it wasn’t McLain?

Because as long as the microphone button is stuck, it will keep recording continuously. It only stops recording if no one is transmitting anything. The phrase “clear 12:34” might be repeated twice in 9 seconds, in case the officer didn’t think his first message got through.

I think only the dispatcher would be giving time checks. But if you can hear the dispatcher or any other radio traffic at all then it’s not stuck continuously.