In 1857, Edouard-Léon Scott de Martinville invented the phonautograph, the first device for making sound waves viewable. It used a membrane (which vibrated in response to sound) attached to a pen, which traced a line roughly corresponding to the sound's waveform onto a roll of paper. Read more
Recording from 1860. Sound restoration.
The Phonautograph Recording from 1860 of 'Au Clair de la Lune' Sound restoration. The first known recording of a human voice, from April 9th, 1860.