Robotic voice effect

"Robot voices" became a recurring element in popular music starting in the second half of the twentieth century. Several methods of producing variations on this effect have arisen.

The vocoder was originally designed to aid in the transmission of voices over telephony systems. In musical applications the original sounds, either from vocals or from other sources such as instruments, are used and fed into a system of filters and noise generators. The input is fed through band-pass filters to separate the tonal characteristics which then trigger noise generators. The sounds generated are mixed back with some of the original sound and this gives the effect.

Vocoders have been used in an analog form from as early as 1959 at Siemens Studio for Electronic Music but were made more famous after Robert Moog developed one of the first solid-state musical vocoders.

In 1970 Wendy Carlos and Robert Moog built another musical vocoder, a 10-band device inspired by the vocoder designs of Homer Dudley which was later referred to simply as a vocoder.

Carlos and Moog's vocoder was featured in several recordings, including the soundtrack to Stanley Kubrick's A Clockwork Orange for the vocal part of Beethoven's "Ninth Symphony" and a piece called "Timesteps". In 1974 Isao Tomita used a Moog vocoder on a classical music album, Snowflakes are Dancing, which became a worldwide success. Since then they have been widely used by artists such as: Kraftwerk's album Autobahn (1974); The Alan Parsons Project's track "The Raven" (Tales of Mystery and Imagination album 1976); Electric Light Orchestra on "Mr. Blue Sky" and "Sweet Talkin' Woman" (Out of the Blue album 1977) using EMS Vocoder 2000's.

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