15.7 Musical examples#
Roger Shepard - Shepard tone (1964)#
The psychologist Roger Shepard constructed a tone that seems to rise in pitch forever [She64]. Each tone is a sum of sine waves an octave apart, whose amplitudes follow a fixed bell-shaped envelope over log frequency. As the tone steps up, components fade in at the bottom and out at the top, so after \(12\) steps, the tone is identical to where it began. The illusion exploits the octave equivalence of pitch classes, and our logarithmic perception of frequency. Here is one that we synthesized, rising by one step every half second for over a minute (\(11\) full cycles):
Video Room 1000#
In Chapter 9, we heard Alvin Lucier’s I Am Sitting in a Room (1969), in which a recording is played back into a room and re-recorded, over and over, until the resonances of the room take over. This homage replaces the room with YouTube. A video was uploaded, downloaded, and re-uploaded, \(1000\) times. Each round trip through YouTube’s lossy audio and video codecs adds a little more distortion, and the artifacts of the codecs gradually take over. This compilation speeds through the generations, pausing on a few along the way.
Diana Deutsch - Sometimes Behave So Strangely (1995)#
While editing a recording of her own speech, the psychologist Diana Deutsch discovered the speech-to-song illusion. When a spoken phrase, “sometimes behave so strangely”, is repeated several times, many listeners begin to hear it as sung, with a clear melody. When they then hear the phrase in its original context, it still sounds sung. The physical sound never changes, only our perception of it.