Dictabelt #10 and the Reluctant Particle Physicist
Wednesday, June 08 2005 @ 11:08 AM EDT
Contributed by: BloodSpite
Carl Haber didn't go looking to investigate the November 22nd murder of John F Kennedy, just this past March.
It came to him.
He and his colleague Vitaliy Fadeyev, at the US Dept of Energy Lawrence Berkeley National Labratory, specialise in making sensors to map the tracks made by sub atomic particles unleashed in physcis experiments.
Their work can also be used to map the microscopic contours of old sound recordings, such as the historic recordings featured at the Library of Congress, but that can be played in any longer due to age and decay.
Thats what Haber was working on. Until Dictabelt #10.
That Dictabelt #10 even exists is, in itself, a story.
By pure accident, a single motorcycle police officer, whom was riding with Kennedy's motorcade during the assisnation, microphone was stuck in the "on" position.
That Microphone transmitted sounds back to the precint where they were recorded, and thus Dicabelt #10 was born
After the assasination Dallas detectives listed to many police Dictabelts. The Dictabelts recorded what was transmitted on 1 of 2 seperate police channels for use as evidence etc.
The Dallas detectives came up empty handed, hearing no gunfire or otherwise.
The FBI, similarly, came up empty handed in early 1964 when they also examined the recordings.
The recordings then sat in a Police Dept file cabinet until 1969 when Officer Paul McCaghren was called to identofy, and hide them "in a safe place"
During this time the Zapruder Film was making headlines, and the public sentiment and qu4estions regarding what really happened boiled back to the surface, especially when ABC News broadcast the movie in March of 1975.
Congress voted to reopen the JFK Investigation.
Then in 1977, Mary Ferrell, a Dallas legal secretary and JFK Researcher, told the newly created House Select Committee on Assassinations that she'd heard an audiotape of Dallas police Radio Traffic around the time Kennedy died.
This led the panel to retrieve the Dictabelts in May 1978. By then, acoustic analysis had come a long way in comparison. The General Counsel chose James Barger a prominet audio scientist, to asses the recordings value.
To make a long story short Barger identified at least 4 sounds that resembeled gunshots.
Three of them closely resemble shots coming from the book depository.
One he identified as coming from the grassy knoll
Two other experts obtained supported those conclusions as well.
That Dictablet, and the findings from it, was one of the keystone reasons behind the Panels 1979 ruling that JFK had probably killed by "Conspirators" who besides Oswald could not be identified.
Others however, did not agree.
In 1980 the Justice Department turned to the National Research Council. In May of 1982 the 12 scientists NRC Panel unanimously ruled that Bargers supposed gunshots were something else.
Dictabelt #10 then went back in to a file cabinet at the Justice Department. It was later transferred to the National Archives.
In 2001 Donald Thomas, published a article based on a mathematical review of the acoustical evidence.
Thomas 's conclusion? 5 Shots. 2 different directions.
*******
Flash forward.
Haber and Fadeyev thought they could salavage old Library of Congress recordings and historical sounds by creating digital recordings of them thru particle physics.
They were right.
They launched their mission by payinga visit to a used record store. Armed with 78 RPM music they scanned the records grooves with a digital microscope known as a Smart Scope. Fadeyev then wrote a software program to simulate the action of a needle traveling the virtual "grooves"
In October 2002 the teo men ran the virtual recording music through that program.
The music played.
The dup published their findings in a paper that was circualted to, among others, the Library of Congress. Archivists there agreed to loan Haber and Fadeyev a batch of early sound recordings in return for an assessment of how they might be preserved.
The two now turned to a unit called a confocal microscope
The Confocal does not scan an entire object, but instead focuses a single beam of light on a small miniscule area, captures the reflection in a photo detector, that, then feeds the measurements in to a computer which assembles a composite from thousands of tiny points.
The first thing they scanned was a so called Edison Cylinder, an early recording medium that is little more than a roll of finely engraved celluloid.
The scan was made of a 1909 cylinder of the song "After the Battle Mother". The resulting digital recording eliminated much of the originals hissing and popping associated with manual playback (such as a cassette desk or record player; white noise).
The duo's success spread among preservationists. When it reached Leslie Waffeb at the National Archives he thought of Dictabelt #10. Worn from countless playings, cracked due to improper storage, it was now considered off limits.
Could Haber save it?
"Its a piece of American history," Waffen says. "Its our job to preserve it and if possible, to make it accessible to the public." (excerpt "The JFK Murder" Readers Digest March 2005 by Jefferson Morley.)
A Fresh digital copy was wanted, so anyone could listen to it.
Last June the 2 made a presentation to the Archives Panel on how they would create just such a copy. The Panel has recommended they attempt it.
The issue now is, can a digital map of the Dictabeltadd clarity to the debate?
Duplication is a major challenge. A Dictabelt groove is 75 microns wide, about as wide as 3 human hairs-and 5 micron deep.
Its also asymetrical, with a steep wall on one sideand a sloping one on the other. The unique shape compicates the jobof writing the algorithims needed to describe it for a computer simulation
BUt they are confident they will succeed. Their next step is to prepare a "proof of concept" paper for the National Archives. If the concept proves valid, the recording will be made available for scanning.
Paul Horowitz a Harvard physics professot and a member of the NRC Panel that dismissed the Dictabelt recordings says it won't add any fire to the debate.
"Digital Playback is not going to change the conclusion"
Don Thomas disagree's.
He says the timing of the Dictabelt sound matches that of the Zapruder films visual indication of gunfire.
He cites a 4.8 second gap on the Dictabelt between what he vies as the third and fourth shots.
"On The Zapruder film, the gap between the crucial 2 shots is 4.8 seconds. Would random noises occur with that exact same timing?"
Fadeyev says its possible a high quality digital map of the Dictabelt could clarify key JFK forensics.
"When the first studies were done, the wave form analysis was fairly primitive." he says
If all goes according to plan, the Dictabelt #10 will be transported across the country to the Lawrence Berkely Lab later this year. Once there Haber and Fadeyev will begin. Within a few months, a digital replica could be produced-a modern version that may shed new light on one of histories most enduring mysteries.
Haber remains hopeful however, 'This (the investigation) isn't what we set out to do. We wanted to try to save the fragile historic recordings of our country."
"We didn't go looking for the murder."
"It came to us"
Comments (0)
Techography
http://www.techography.com/article.php?story=20050608080856182