The 10-second clip of a woman singing "Au Clair de la Lune," was recently discovered by audio historian David Giovannoni. The recording predates Thomas Edison's "Mary had a little lamb" — previously credited as the oldest recorded voice — by 17 years.
The tune was captured using a phonautograph, a device that created visual recordings of sound waves by using a needle that moves in response to sound. The phonautograph etched sound waves into paper coated with soot from an oil lamp.
Read more and find a link to the recording which will be played in public on today at the annual conference of the Association for Recorded Sound Collections at Stanford University here:
http://ap.google.com/article/ALeqM5g2WqnQ_-2fPrNuC62Vy9dn5fQ1mAD8VM3U3G0