Music 171 homework 7

Psychoacousticians have long been interested in the phenomenon of streaming, in which a succession of sounds is heard as a single stream, like a melody or a person speaking. Cues that might contribute to hearing sounds as belonging to a stream might be proximity in time, pitch, amplitude, timbre, or physical location, This assignment is to reproduce a famous experiment of David Wessel (from the paper, "Timbre Space as a Musical Control Structure", 1979). In the experiment a loop of six sounds is heard as a single stream if cycled slowly, but as two separate ones if cycled more quickly. The sounds in the loop could be made by filtering wavetable oscillators, for instance as shown:

 65   75
 69   110
 72   75
 65   110
 69   75
 72   110
 60   75
 64   110
 67   75
 60   110
 64   75
 67   110

The two timbres should be quite different from each other, although the sounds of both timbres should have a clear pitch (i.e. they should be periodic tones). In this assignment you can make them using a fixed waveform and filtering with "vcf". The illusion works best if the notes are separated in time, i.e., each one should turn off smoothly and the next one should turn on smoothly; don't just change the pitch while the note is playing.

To make the patch:

The output at the slow setting should sound something like this and the faster one like this.

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