2013 hears the voice of Alexander Graham Bell

Nine years after he placed the first telephone call, Alexander Graham Bell tried another experiment: he recorded his voice on a wax-covered cardboard disc on April 15, 1885, and gave it an audio signature: ‘Hear my voice - Alexander Graham Bell.’

The flimsy disc was silent for 128 years as part of the Smithsonian Museum’s collection of early recorded sound, until digital imaging, computer science, a hand-written transcript and a bit of archival detective work confirmed it as the only known recording of Bell’s voice.

Carlene Stephens, curator of the Smithsonian’s National Museum of American history, first saw this disc and nearly 400 other audio artifacts donated by Bell when she joined the museum in 1974, but she didn’t dare play them then.

‘Their experimental nature and fragile condition ... made them unsuitable for playback,’ Stephenssaid by email.

‘We recognized these materials were significant to the early history of sound recording, but because they were considered unplayable, we stored them away safely and hoped for the day playback technology would catch up with our interest in hearing the content,’ she wrote.

That day came in 2008, when Stephens learned that scientists at the Lawrence Berkeley National Laboratory in California had retrieved 10 seconds of the French folk song ‘Au Clair de la Lune’ from a 1860 recording of sound waves made as squiggles on soot-covered paper. That was nearly two decades before Thomas Edison’s oldest known playable recording, made in 1888.

If the Berkeley scientists could coax sound out of sooty paper, Stephens reckoned, perhaps they could decipher those silent records she had guarded for decades.

She contacted Carl Haber at Berkeley and Peter Alyea, a digital conversion specialist at the Library of Congress. They chose six recordings from the collection, including the one that turned out to be the Bell audio, and made ultra-high-definition three-dimensional images of them.

The Berkeley lab’s scanner captures gigapixels of information, and not just width and height but the depth of the grooves, with measurements down to 100 nanometers, or 250 times smaller than the width of a human hair, Haber said by telephone.