Combining Optics and Audio to Save Historical Recordings

My sister-in-law works as an archivist, and from what I hear her daily work is pretty much what you'd expect of the job. She spends a lot of time in dark basements, has frequent attacks of dust-triggered sinusitis, sometimes wears white gloves, and most importantly preserves and catalogs old books and papers so they can be accessed by future researchers.

Preserving physically readable materials like books is relatively straightforward, but archivists have run into well-documented problems preserving system-dependent materials like computer files or sounds. In the case of the latter, the earliest examples of recorded sound are becoming more and more difficult to access and play back. Disc records are now generally limited to hi-fi enthusiasts, and maybe 0.5% of the population has ever seen a cylinder phonograph in person, so archivists have been concerned that early recordings may be lost forever.

The US Library of Congress is fighting against that tide thanks in part to IRENE, a device developed at Berkeley Lab by researchers recycling particle physics methodologies. IRENE uses high-res optical technologies to take millions of images of a grooved recording medium and converts the grooves into a sonic waveform. Using optical rather than audio technology has two primary advantages: avoiding further wear on 100+ year old grooves by limiting contact, and the ability to reconstruct sound from broken or unplayable discs or cylinders.

IRENE's name is derived from the first audio extraction performed, a Weavers recording of "Goodnight, Irene," but its name has since become a backronym for "Image, Reconstruct, Erase Noise, Etc." The machine made a splash in 2008 when it reconstructed audio from an 1860 phonautogram recording of the French folk song "Au Clair de la Lune." Prior to this discovery, researchers figured Edison recordings of the 1870s to be the earliest surviving recorded sounds. (True to internet fashion, the entire experimental discography of Édouard-Léon Scott de Martinville, who invented the phonautograph, is on YouTube.)

IRENE has been successfully employed in extracting audio from a wide variety of media since 2008, including Alexander Graham Bell's Volta Labs experiments. The beauty of using optical technology is seen in the last of these examples, an artifact consisting of a wax disc still attached to a primitive recording machine. Researchers simply placed the scanner's beam over the disc and used an external drive to rotate the machine, preserving both the disc and machine.

In a more recent sound preservation effort, the Library of Congress held a Radio Preservation Task Force symposium in late February, part of a larger collaborative effort to preserve early radio recordings. That conference was inspired by a 2013 LoC report that found that many important historical broadcasts were either untraceable or had been destroyed entirely, and that unlike other archival areas, "little is known of what still exists, where it is stored, and in what condition." Seeing as how radio was once the dominant medium for real-time news broadcasts and discussion about niche topics, rediscovery of historic recordings, although it rarely occurs, is a big deal.

Archivists have had perhaps more pressing issues on the digital front as well. Although digital files take up significantly less physical space, they're prone to system compatibility issues resulting from the exponential growth of computing equipment. Whether it's wax cylinders, radio broadcasts, or digital files, sound archivists continue to dutifully perform important, and often thankless, preservation work.

Image credit: Library of Congress Blog