An early phonautograph (1859). The barrel is made of plaster of paris.

Detail of a phonautogram made in 1959

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 in 2008, thanks to computer technology.

The device consisted of a horn or barrel that focused sound waves onto a membrane to which a hog's bristle was attached, causing the bristle to move and enabling it to inscribe the sound onto a visual medium. Initially, the phonautograph made recordings onto a lamp-blackened glass plate. A later version (see image) used a medium of lamp-blackened paper on a drum or cylinder. Another version would draw a line representing the sound wave on a roll of paper. The phonautograph was a laboratory curiosity for the study of acoustics. It was used to determine the frequency of a given musical pitch and to study sound and speech; it was not understood at that time that the waveform recorded by the phonautograph was in fact a recording of the sound wave that needed only a playback mechanism to reproduce that sound.

	Au Clair de la Lune This 1860 phonautogram by Édouard-Léon Scott de Martinville is the oldest known recognizable recording of the human voice. It is currently played at twice the correct speed.
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	Au Clair de la Lune The recording slowed down revealing a man's voice, presumably that of Scott de Martinville. http://www.firstsounds.org/sounds/scott.php.[1]
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In 2008, phonautograph recordings were for the first time played back as sound by American audio historians.^[2][3] The team accessed Leon Scott's phonautograph papers which were stored in France's patent office and the Académie des Sciences. They then optically scanned the etched paper recordings into a computer program developed a few years earlier for the Library of Congress. The sound waves on the paper were then translated by the computer into audible sounds. One recording, created on April 9, 1860, was revealed to be a 10-second recording (low fidelity but just recognizable) of the French folk song "Au Clair de la Lune". While it was initially believed to be the voice of a woman or adolescent, further research in 2009 suggested the playback speed had been too high, and that it was actually the voice of Scott himself.^[4]

A phonautogram containing the opening lines of Torquato Tasso's pastoral drama Aminta has also been found. Recorded around 1860, probably after April 9, this phonautogram is the earliest known recording of spoken human speech to be played back,^[5] predating Frank Lambert's 1878 recording of a talking clock and the Edison Company's 1888 phonographic recording of a Handel concert. Earlier recordings made in 1857 contain Scott's voice, too, but are unrecognizable due to the irregularity of speed.

[edit] References

[edit] See also

• Autopen
• Pantograph

[edit] External links

• Édouard-Léon Scott de Martinville's Phonautograph Patent No. 31470. The original patent (25 March 1857) and the subsequent certificate of addition (29 July 1859).
• FirstSounds.org, an informal collaborative aiming to make mankind's earliest sound recordings available to all people for all time.
• The Phonautographic Manuscripts of Édouard-Léon Scott de Martinville (PDF), containing French and English texts of all Scott's known writings about the phonautograph from the 1850s and 1860s.