They’ve been using imaging technology to listen to unplayable experimental recordings by non-destructive means, and accidentally hit upon this snatch of audio, in which the speaker says, “In witness whereof—hear my voice, Alexander Graham Bell.”
You have to click the link the hear it, since I can’t embed it, but here’s a bit of the back story:
Today, however, a dramatic application of digital technology has allowed researchers to recover Bell’s voice from a recording held by the Smithsonian—a breakthrough announced here for the first time. From the 1880s on, until his death in 1922, Bell gave an extensive collection of laboratory materials to the Smithsonian Institution, where he was a member of the Board of Regents. The donation included more than 400 discs and cylinders Bell used as he tried his hand at recording sound. The holdings also documented Bell’s research, should patent disputes arise similar to the protracted legal wrangling that attended the invention of the telephone.
Inside the lab, Bell and his associates bent over their pioneering audio apparatus, testing the potential of a variety of materials, including metal, wax, glass, paper, plaster, foil and cardboard, for recording sound, and then listening to what they had embedded on discs or cylinders. However, the precise methods they employed in early efforts to play back their recordings are lost to history.
As a result, says curator Carlene Stephens of the National Museum of American History, the discs, ranging from 4 to 14 inches in diameter, remained “mute artifacts.” She began to wonder, she adds, “if we would ever know what was on them.”
Then, Stephens learned that physicist Carl Haber at the Lawrence Berkeley National Laboratory in Berkeley, California, had succeeded in extracting sound from early recordings made in Paris in 1860. He and his team created high-resolution optical scans converted by computer into an audio file.