Technology for recording sound has been around a lot longer than many people realize, long enough that some very interesting people we now think of as distant historical figures made recordings of their voices–people like Queen Victoria, Alfred Tennyson and Florence Nightingale. We seldom hear those recordings, though, because they’re so fragile that playing them could destroy them. New technology could change that.
In 1877, Thomas Edison was experimenting with a way to repeat Morse-coded telegraph messages using a waxed paper tape on which the message was written by a stylus. He noticed that if he pulled an already inscribed tape past the stylus it produced a note, and reasoned that he should be able to use the same kind of system to record notes of his choice and play them at will.
The “phonograph” that resulted had a stylus that followed a spiral groove on a tinfoil-covered drum. Sound vibrated a diaphragm, which vibrated a stylus, which made indentations in the groove. Running the stylus through the indented groove reversed the process, causing the diaphragm to vibrate, reproducing the word “Halloo,” in Edison’s first successful attempt. (The oldest verified surviving recording is an 1878 tin cylinder of a talking clock.)
A needle following a groove became the basis of a new industry. Edison’s cylinders led the way for years, but disks, introduced by Emile Berliner in1888, eventually supplanted the cylinders because they could be more easily mass-produced.
There are a couple of obvious long-term problems with this technology. One, the groove is very sensitive to dust and scratches; we’re so used to clean digital sound these days that we forget (those of us who are even old enough to remember) how we used to put up with hisses and pops as a matter of course. Two, the mere act of playing such a recording damages it; the needle can’t help but scrape away a small part of the recording medium with every pass.
The earliest recordings are also at risk of physically disappearing. Many early recordings were made on wax cylinders, which over the years have been devoured by fungi and insects. It’s estimated that at least half of the wax cylinders used to record sound before 1902 are gone.
But now we may be in a better position to preserve what remains than ever before–and not only to preserve it, but also to improve it.
Vitaliy Fadeyev and Carl Haber of the Lawrence Berkeley National Lab were working on a European-led particle physics project when Haber heard a radio report about the problems with preserving and accessing old sound recordings. He realized that his work with Fadeyev could be applied to the problem.
Haber and Fadeyev were responsible for making arrays of sensors for tracking subatomic particles in particle accelerators. In order to align those arrays, they scanned the sensors with a special tool called an OGP SmartScope, a four-axis measuring machine that uses a digital camera to capture highly magnified images and a computer to analyze and map the shapes and locations of the objects being examined.
The two scientists set out to use the SmartScope to map and photograph the undulating grooves etched in old recordings. That data could then be used to create a digital version of the recording.
They went to work first on a circa-1950 78-rpm shellac recording of “Goodnight Irene” by The Weavers. Besides scanning the grooves, they also had to write software that could calculate the velocity at which a stylus would move within the scanned grooves. The result was a digitized sound clip that sounded better than the same section played back from the original disc with a stylus.
Working with other U.S. and British researchers, the Berkeley scientists have now shown that the approach can also be applied to much older recordings: they successfully used it on a 1909 wax cylinder, featuring a recording of the Civil War-era popular song “Just Before the Battle, Mother.” Because of its cylindrical shape, they had to use a special instrument called a confocal microscope that allowed for three-dimensional scanning.
The only drawback right now is that with existing equipment, it could take a full day to scan one full wax cylinder. The scientists are working on speeding up the process–vital if the technique is to achieve widespread use, since the Library of Congress alone has 128 million recordings in various formats.
It’s an exciting project–a kind of high-tech throat lozenge for the laryngitis of the past.
