"Voice Crack was a Swiss electronic free improvisation group. Formed in late 1972 by Andy Guhl and Norbert Möslang, Voice Crack were initially a free jazz duo. They began incorporating pre-recorded tape effects and live sound processing, and by 1983 they eliminated any normal instrumentation in favor of what they call “cracked everyday electronics:” Mundane objects such as “radios, turntables, transmitters, dictating machines” and other items are cracked open and manipulated to produce “new sounds using magnetic and radio waves in a complex system controlled by movements of their hands and by light. The resulting music - which consisted of various overlapping buzzes, clicks, drones and oscillations - has been described as, “Cascading magnetic waves arc across the sky as three-headed critters race and rummage through alien flora … or at least that’s what it sounds like.”; and was favorably compared to some of John Cage’s work”

http://en.wikipedia.org/wiki/Voice_Crack