John Cage made Variations V in 1965 for the Merce Cunningham Dance Company. He and David Tudor settled on two systems for the sound to be affected by movement. For the first, Billy Klüver and his colleagues set up a system of directional photocells aimed at the stage lights, so that the dancers triggered sounds as they cut the light beams with their movements. Ten photocells were wired to activate tape-recorders and short-wave radios. Cecil Coker designed a control circuit, which was built by Klüver's assistant Witt Wittnebert. The photocells were located at the base of the five-foot antennas placed around the stage. Cage, Tudor, and Gordon Mumma operated equipment to modify and determine the final sounds. A second system for dancers' triggering sound was designed by Robert Moog and used a series of antennas. When a dancer came within four feet of an antenna, a sound would result. Film footage by Stan VanDerBeek and Nam June Paik’s manipulated television images were projected on screens behind the dancers.
In 1989 Tudor described the sound system in detail: “Basically, the materials were simple enough; it was the implementation of it which makes it appear to be extraordinarily complex. [...] John tried to make sure that there was enough material so it would be extraordinarily varied. [...] John had made some recordings. One of his next door neighbors had a drain which was completely out of order, so he made some very significant recordings of those drains. The other source was shortwave radios, and we had a kind that you won’t find today unless [...] you go down highway one you might find some. but they are the kind that the Navy and the Army used to use, so that you have a receiver which goes maximum 3 Mega cycles with ultimate control so that you get the wildest possible kinds of sounds. Like the whistling sounds [...] those were shortwave signals, but they are very powerful. If you look at a contemporary shortwave radio, you won't get it, because you won’t have the signal amplitude, the receiver doesn't have the strength. [...] Then a third source was contact microphones which the dancers had some objects which they themselves could activate. Merce Cunningham had a bicycle which was rigged up so that there was a contact microphone which was receiving the impulses of the wheel spokes, which was wired into an amplifier and a loudspeaker which the bicycle itself was carrying so that was whirling around the stage. Then the whole thing was turned on and off, so one never knew what was going to happen, the musician's job was to keep this material going so that there was a constant supply of sound and the whole thing was triggered by the dancers, what position they were in, and it was never the same. I mean six things could be triggered at once, and sometimes nothing was happening though you heard a dancer moving a plant which was miked. It was a lovely situation once it got organized. Before that it was absolute chaos.”
(A Kind of Anarchy: Merce Cunningham and Music (September 19, 1989) [video recording],” MGZIDVD 5-469, Merce Cunningham archives, New York Public Library.)