I began to use oscillators; this is what my electronic music was. I used oscillators tuned to high frequencies above hearing that would produce difference tones-- the difference between any two frequencies would be audible in this system. I used only, in the first pieces, 2 or 3 oscillators to start with, but the beat frequencies or difference tones and the bias frequencies of the tape recorders, the tape heads themselves, were generated between those oscillators. So I created a system that was quite unstable, but very interesting, and I could use it to create a vast variety of sounds. Later, I was at the University of Toronto for a summer with a bank of twelve oscillators that I could key or turn on from a keyboard and then play with the dials. I made "One of Four" there, which is a kind of classic electronic piece using that method.
I'm very interested in the physicality of making music. I was trained as a performer all my life, and I like to be in physical contact with the sound. Having this expanded instrument system allows me to perform the music and maintain that physical contact with the sound. I've made in the '60's, of course, tape pieces; pieces that were recorded on tape, like "One of Four" for example, which is fairly well known amongst people who are familiar with new music. I performed that piece in the studio in real time. In the studio at the University of Toronto there was a four-channel system. As I played this piece, it was in four-channel and I was in the middle of it, but the documentation of the performance was stereo. Incidentally, there was no mixer so I was just patching signals. The truth of that piece is that no one could hear it now the way I heard it as I performed it. I think there was one other person present when I made that piece. And that piece has what we refer to as a 'screamer' in it-- there's an incredible melody that comes out. I remember when it happened, and it was very surprising and wonderful. I was laughing as it happened. All of that is kind of the history of the piece, but those tracks, those two extra tracks of the four-channel system were virtual, and they don't exist except in the mix that resulted in the recording of the recording in the second machine.