Berkeley scientists rescue historic sounds

by Glennda Chui, Knight Ridder Newspapers, August 12, 2004

San Jose, Calif. – No one has heard Thomas Edison’s first recordings since they were made on fragile scraps of tinfoil. No one has heard Queen Victoria’s voice since she died. And no one listening to the only known recording of President John F. Kennedy’s assassination has been able to say just how many shots were fired.

Now physicists at Lawrence Berkeley National Laboratory may have a way to rescue those sounds from the deterioration of the years, allowing history to be heard as never before.

It could also offer a way to quickly restore and digitize millions of old recordings — from Dixieland jazz to field recordings of folk music an radio newscasts from World War II – making them widely available for the first time.

The researchers make microscopic images of the grooves that etch the sound into a wax cylinders or phonograph record. Then a computer turns the wiggles, bumps and ridges into a digital soundtrack, subtracting the scratches and hisses to let the true, clear voice come through.

The technology was developed to capture the fleeting tracks of quarks and other particles in giant accelerators. It is the brainchild of Carl Haber and Vitaliy Fadeyev, physicists at Lawrence Berkeley who make instruments for detecting subatomic particles.

Four years ago, they heard a report on National Public Radio about the fragile state of old recordings in the Library of Congress. Of the 2.5 million recordings in the library’s collection, 1.5 million are on wax cylinders or discs, which are especially vulnerable to damage.

The report got the physicists thinking: What if they could analyze the recordings the same way they track particles, examining them with a digital video recorder that is guided by a computer?

“You could figure out what shape the groove in a record is, and then analyze it optically instead of playing it,” Haber said. “There are damaged and delicate cylinders and discs they just don’t want to touch anymore. If you could read them without touching, you might be able to bring them back.”

Haber said researchers from a number of fields have already contacted the team to see if they can help rescue old recordings: A linguist wants to hear the century-old voices of the Yurok Indians. Another scholar longs to hear the voice of Bertrand Russell.

In England, he said, there is apparently one wax-cylinder recording of Queen Victoria in existence; she reportedly resisted having her voice recorded because then any commoner could command the queen to speak. That lone recording is too fragile to be played; now her voice may be heard again.

Then there are Thomas Edison’s earliest recordings, most of which are in the hands of private collectors. They were made on pieces of tin foil wrapped around cylinders, said Sam Brylawski head of the recorded sound section at the Library of Congress. Once a piece of foil was removed from its cylinder, it could not be played again. So these tin snippets have not been heard by anyone since.

The National Archives has also asked Haber and Fadeyev to look at the possibility of analyzing a Dictaphone belt that is the only known recording of the assassination of President Kennedy. It was made by an open microphone on a policy motorcycle in Kennedy’s motorcade, which fed sound into a Dictaphone at police headquarters.

The belt, a clear loop of thin plastic, is broken and damaged, and the sound is extremely scratchy, Haber said.

Scientists have examined it over the years, but have been unable to agree whether the belt recorded three gunshots or four – crucial information for determining how many gunmen were involved.

“I’ve heard the Kennedy tape. It’s very hard to hear anything,” Haber said. If the shots are obscured by noise in the background or from the police radio, “there’s nothing we’re going to be able to do about it,” he said. “That’s genuine audio.”

But if the problem is from damage to the belt itself, he said, the method may be able to clear it up.

“It’s a maybe,” Haber said. “I refuse to oversell the technology – in physics, or in whatever we do.”

The sound in a phonograph record is contained in a single V-shaped groove that spirals from the edge of the disc inward. The top of the groove is about six times the width of a human hair. The groove wiggles slightly from side to side, and those wiggles contain the sound.

The Berkeley scanner can pick up details as small as one-50^th the width of a hair.

Then the computer automatically analyzes the images; it recognizes sceatches and bits of dust, removes them and smooths over the gap by patching it with sound from either side.

The effect is stunning.

An original 1909 recording of the song “Just Before the Battle, Mother” is a thicket of hissing and crackling. But the version that emerges from the Berkeley scanner, which has been further cleaned up with modern sound filtration techniques, lets the schmaltzy voices of the crooners come through almost as if they’d been recorded on CD.

“These methods pull 10 to 20 more times information off the surface than a needle does,” Haber said.

The Berkeley scientists have asked the Library of Congress to fund another year’s work to make the system quicker and more user-friendly. Scanning a three-minute recording on disc now takes hours; they’d like to cut that to five to 15 minutes, and automate the process so it’s as easy as using a copy machine.

The library has also given them a grant to develop a system for wax cylinders, many of which are damaged by a coating of brown mildew.

“We’re hoping the technique can provide better reproduction,” Brylawski said, and help the library achieve its goal of translating its collection into digital form so it is accessible to the public.

“It shows promise as a mass medium for making things more accessible,” he said, “and also as a preservation medium for things at significant risk.”