Pea Soup (1974; revised 2001-2014)
I composed Pea Soup while a student at Wesleyan University. A self-stabilizing network of analog circuitry (originally three Countryman Phase Shifters) nudges the pitch of audio feedback to a different resonant frequency every time the feedback starts to build. The familiar shriek is replaced with unstable patterns of hollow tones, a site-specific raga reflecting the acoustical personality of the room. These architectural melodies can be influenced by moving in the space, making other sounds, or even by letting in a draft of cold air. The piece existed both as an installation, responding to visitors, and in a concert version, in which people performed activities intended to influence the feedback.
In the late 1990s I tried to replicate the now unavailable Countrymen, and by 2002 developed a fair emulation in software, which I return to for minor tweaks on a regular basis. Thirty years on I began touring the piece again, and re-positioning what was a typical 1970s task-oriented work of strict Minimalism with a freer occasion for "improvising with architecture."
By 2014 I had accumulated recordings of over 70 performances of Pea Soup. Working with a former graduate student I developed Pea Soup To Go, a web app that plays back the various audio files in pseudo-random order, with long cross-fades, to create a seamless mix that slowly modulates from one "room key" to another. The app was launched on October 26, 2014 -- the 40th anniversary of the first performance of Pea Soup.
Here are links to some recordings and documentation: