This is a guest post written by Peter Alyea. Peter is a Preservation Science Specialist in the Research and Testing Division of the Library of Congress and has been working with Lawrence Berkeley National Laboratory on imaging recorded sound collections for preservation and access since the inception of the IRENE project.
Although making audio recordings today is as trivial as unlocking your phone and pressing a button, the technical innovations that kicked off the recorded sound era were revelatory at the time. The first sound recordings ever made were with a device called the phonautograph invented by Édouard-Léon Scott de Martinville and patented on March 25th, 1857. The phonautograph was not designed to reproduce sound but produced a visual representation of the sound waves on paper. This important step towards recording and reproduction of audio echoed, almost a century and a half later, the usefulness of visualizing sonic events that are naturally invisible to our eyes.
The vinyl disc that still survives today is the culmination of many early formats that also included the popular cylinder record. These historic audio formats inscribe the sounds as tiny motions in a groove on the media’s surface. Reproduction of the sound is achieved by riding a stylus in the groove that vibrates in response to these dislocations which can eventually drive speakers and recreate the sounds that we can hear. Although the patterns in the groove of a record were designed to be traced with a stylus in motion, they can also be examined as a static pattern with modern imaging equipment.
In the early 2000’s, physicists at Lawrence Berkeley National Laboratory started experimenting with the idea of using a high-resolution microscope to scan the surface of a disc to extract the sound. This work eventually resulted in a collaboration with the Library of Congress to develop methods and tools to help preserve recorded sound collections. With the ability to image in two and three dimensions the IRENE (Image Reconstruct Erase Noise Etc.) System preserves sound from a wide variety of historic audio media formats and is named after the first disc imaged at Berkeley Lab, “Goodnight, Irene” as performed by The Weavers.
Imaging in two dim