There are recordings from circa 1860 that have been processed and played back.
As I recall, the recordings were made by a man speaking/singing into a the wide end of a cone and recorded by some kind of vibrating brush or pen or marker of some sort onto paper or a card or strip. The result was a linear waveform. No means for any kind of playback existed until recently. The man was singing Clair de Lune I think and you can actually hear it. Cool stuff.
Looking forward to this! I need to learn much more about it.