Sounds and the Shadows of Sounds

Installation 1979

A computer quietly listens for pitched sounds in the environment for a while, analyses what it hears, then plays the spectral "shadows" of its memories as slowly shifting patterns of filtered white noise from the interchannel hash of a police scanner.

Materials: custom 36-channel resonant filter-bank controlled by Kim-1 Computer, Radio Shack police band radio, Gentle Electric pitch follower, microphone, loudspeakers, ambient sound, filtered white noise.

Exhibited at: 80 Langton St., San Francisco, January - March 1980
Media Studies, Buffalo, NY, December 1980

When Isaac Newton coined the term "spectrum" to refer to the colors of the rainbow he had in mind the idea of the spirit world - that the individual colors that make up white light are somehow the "ghosts" of light. This term has been applied analogously to sound and to all manners of signals that can be represented in the frequency domain. Sounds and the Shadows of Sounds retains this spirit in the means of its operation. A specialized analog circuit, the Gentle Electric pitch follower, designed by Carl Fravel, supplies a Kim-1 computer with information about pitched sounds in the environment. The computer keeps track of these and updates a series of histograms which it uses to control a series of 36 bandpass resonant filters that cover the audio spectrum, resulting in a slowly shifting composition made of filtered white noise. The noise source is the inter-station noise from a police-band radio tuned between stations, not ideal acoustically, but which serves as a channel of contact with another world.