The phonautograph was the earliest known invention of a sound transcription device. It was invented by Frenchman Édouard-Léon Scott de Martinville and patented on March 25, 1857. It could transcribe sound to a visible medium, but had no means to play back the sound after it was recorded. The transcriptions, known as phonautograms, were first successfully played back using computer technology in 2008. The device consisted of a horn or barrel that focused sound waves onto a membrane to w… (More on Phonautograph)