In 2008, scientists at the Lawrence Berkeley National Laboratory used digital imaging machine to play back the oldest known recordings of the human voice. Now, the machine is being used by The Library of Congress.
Both Pesco and I wrote about the oldest audio recordings. (Check out those older posts to see and hear an audio recording from the 1850s.) The recordings were difficult to play back because they weren't really meant to be played back. The inventor, Édouard-Léon Scott de Martinville, was, instead, trying to figure out what sound looked like. So the researchers at LBNL had to come up with a way to take what was essentially a 2D "drawing" of sound and turn it into sound waves you can actually listen to. At The Atlantic, Adrienne LaFrance has a story about the technology that made that possible. It's called IRENE.
How IRENE works: It's basically a digital-imaging device. So, say you have a vinyl record you want to preserve. IRENE scans the topography of the disc, and sends the images it produces to a computer. Separate software on the computer then converts those images into sound.
"You have optics that magnify the surface of the disc," Alyea said. "You have a laser that actually drives a motor that moves the whole system up and down like the autofocus on your camera. Most of these discs are not flat at all and there's a fairly small area of focus. Some light comes in here and is split and shone directly on the surface of the disc, and then there's a camera." More simply, IRENE is a mapping device that tracks the terrain of a recorded medium—like the pattern of the grooves etched onto a flat vinyl record.
The device knows how to image the architecture of other recorded formats, too, including older shellac-coated vinyl, and glass records like the ones made during the rationing of World War II. In the ten years since IRENE was invented, institutions have discovered a spate of esoteric formats and unknown recordings, strange items in long-forgotten collections that haven't even been catalogued.
Thanks, Howard Koerth!