A recording made in St. Louis in 1878 has recently been digitized so we could hear it without damaging the original medium.
It is the oldest "playable" American voice recording. Speaking of audio recording medium, this voice and cornet were recorded on a piece of tin foil using the Edison phonograph. And you think YOU have it hard;).
Researchers mapped the groove's (it was just one long groove) contours and fed the information into a computer, which converted it to audio to make it audible in the same basic way it would have been done in 1878. It's really amazing.
Take a listen to it here - HistoryofInformation