I of IV (1966) by Pauline Oliveros was composed in real time, no editing, no splicing. The materials consist of two stereo tape recorders, a couple of mixers, twelve audio oscillators, and reverb. Guess why there would be twelve oscillators in this studio? An- swer: the twelve notes of the scale. In making I of IV Pauline used two kinds of delaying techniques: head delay and tape delay. On any professional tape recorder the audio tape passes over three heads: the erase head which erases any pre-recorded material that might be on the tape; a record head which records the sounds of the input signal; and a playback head which plays back the re- corded sounds. Most good machines have an A/B switch, which enables you to hear what is being recorded and what is being played back. Since the heads are physically spaced apart, you can get short time lags between what goes in to the machine and what comes out. The distance between the record and playback heads varies from machine to machine. A distance of two inches gives a 266 millisecond (a quarter of a second) delay, if the tape is run- ning at 7.5 inches per second, 133 ms at 15 ips. Pauline calls that reiterative delay. Did any of you see the movie Patton? As George C. Scott (Patton) is looking over an ancient battlefield in Sicily, you hear a trumpet call overlapping itself several times at short intervals. It was probably made with head delay. You’ve heard that effect every once in awhile in movies and on television. You can in addition feed the playback signal back into the record head, causing reverberation. Pauline got longer, eight second delays by threading the tape from the supply reel on the first recorder to the take-up reel on the second, positioned five feet away: eight sec- onds at 7.5 ips equals sixty inches.
You can feed anything you want back into anything you want. You could take the record head signal, take the playback signal, bring it back into the record head. There’s no reason you can’t make feedback loops within the machine itself, by feeding the playback output back into the record input and so forth. For sound sources she used eleven sine waves (pure waves, no overtones), and one square wave (rough sounding, every odd overtone). The sine waves were tuned above audibility (20,000 cps), the square wave, below one cycle. Combination tones were created among the high frequency oscillators, plus the bias frequency of the re- corder. All were pulse-modulated by the sub-audio signal. They all go through reverb, which gives them spaciousness, some through reiterative short delays, others through longer tape delays.
Tape delay was a wonderful tool to make electronic music in live performance. The trick is to design the configuration in such a way that the delays are not heard as periodic. You have to be able to forget them. Let’s play a little of I of IV. It sounds like a living organism. Let’s listen for things to come back. Oh, I love that one! When is it going to come back? There it is! You can measure the length of the delay by listening for when the sounds return. It’s wonderful to talk about these old-fashioned compositional tech- niques. It’s like talking about the viola da gamba.
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