Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. 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."