NMSAT :: Networked Music & SoundArt Timeline

1942 __ Vocoder
Claude Elwood Shannon (1916-2001) (1912-1954)
Comment : Between 1942 and 1945, while working for Bell laboratories and the British Secret Service, respectively, Shannon and Turing developed the vocoder, a wonder weapon (wunderwaffe) which was to make the transatlantic telephone conversations between Churchill and Roosevelt safe from interception by Canaris and the German Abwehr, and which, like so many electronic achievements of the Second World War, is now indispensable to popular music. It lives up to its name: it encodes any given data stream A with the envelope curves of another sound sequence B, for example the voice of a singer, after a switching matrix has by way of free permutation changed the frequency of the envelope curves by way of free permutation. [...] In order to test his vocoder, by the way, Turing first played a record of Winston Churchill's belligerent voice, whose discreet or cut-up sampled values he then mixed with a noise generator using modular addition. Whereupon British officers heard the voice of their prime minister and commander-in-chief contaminate the speakers as just so much white noise (not to say, primal sound). Appropriately, Turing's vocoder was named after Delilah, who in the Book of Judges tricked another warrior, the Danaite Samson, out of the secret of his strength. Turing's skill as a tinkerer, however, revealed the secret of modern political discourse to be something far worse than weakness: "a perfectly even and uninformative hiss" which offered no regularities and, therefore, nothing intelligible to the ears of British officers or those of German eavesdroppers. And yet, sent through the vocoder a second time, Churchill's original voice emerged from the receiving end. (Friedrich Kittler)
Source : Kittler, Friedrich A. (1986), “Grammophon Film Typewriter”, Berlin: Brinkmann & Bose; and also, “Gramophone, Film, Typewriter”, translated by Geoff Winthrop-Young and Michael Wutz, Stanford: Stanford University Press, 1999.
Urls : http://www.stanford.edu/class/history34q/readings/Kittler/GramFilmTypwriter/Kittler_Gramophone.html (last visited )

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