Listen carefully to the oldest sound ever recorded. The year is 1860, and a woman is singing “Au Clair de la Lune” into a barrel-shaped horn, which causes etchings to be inscribed on a soot-blackened piece of paper. Called a phonautogram, it’s one spooky blast from the past. Listen to it. Its ghostly sound is eerie to be sure, but it's recognizable as that old song that was a hit before your great-great-grandmother was born.
They had no idea how to play back such things in those days, but we do now, using optical imaging and a “virtual stylus” developed by U.S. audio historian David Giovannoni. The inventor of the ancient (and first) recording process, Édouard-Léon Scott de Martinville, was understandably angry at all the attention given to Thomas Edison, who got credit for making the first audio recording 17 years later.