Sounds and information on Édouard-Léon Scott de Martinville’s first recordings on the First Sounds project archive:
http://www.firstsounds.org/videos/
Principes de Phonoautographie (1857 publication)
John Cage’s “Imaginary Landscape #1”, 1939:
Pierre Schaeffer’s “Etude aux chemins de fer”, 1948 (musique concrète):
Karlheinz Stockhausen’s “Etude II”, 1954