Volta Laboratory Experimental Sound Recording, Glass Disc

Volta Laboratory Associates · 1884-11-17

This experimental sound recording was made in the Volta Laboratory, Washington, D.C., on 17 November 1884. The recording process involved focusing a beam of light, projecting it through a liquid, and causing sound waves to interrupt both the light and the liquid to expose a prepared photographic plate. This is a variable-area recording, that is, sound is represented by a spiral of that varies in width according to volume and pitch. The process is described in U.S. Patent 341,213 awarded Alexander Graham Bell, Chichester A. Bell, and Charles Sumner Tainter on 4 May 1886.