1 янв 1857 г. - Phonautograph

Описание:

The Phonautograph was invented by Édouard-Léon Scott de Martinville in 1957. It replicated sound waves as undulations or other deviations in a line traced on smoke-blackened paper or glass. Intended solely as a laboratory instrument for the study of acoustics, it could be used to visually study and measure the amplitude envelopes and waveforms of speech and other sounds, or to determine the frequency of a given musical pitch by comparison with a simultaneously recorded reference frequency.