Pitch Control and Pitch Paradoxes Demonstrated with Computer-Synthesized Sounds

Abstract

Using computer-generated sounds, R. N. Shepard has demonstrated circularity in judgments of relative pitch [J. Acoust. Soc. Amer. 36, 2346–2353 (1964)]. Other unusual sounds will be presented, including endlessly descending glissandi; a succession of periodic tones that are perceived as going down in pitch although the final pitch is perceived as higher than the original pitch; successions of periodic tones that are perceived as going both up and down in pitch. Most of these sounds consist of octave components; the fundamental frequency can be varied and the spectral envelope can be shifted, independently of the fundamental frequency, along the frequency axis. The way some of these sounds are perceived supports the view that pitch perception cannot always be adequately represented by a linear scale, but rather implies a circular component (“tonality”) and a linear component (“tone height”), which can vary independently for specially contrived stimuli. [Work supported by the Délégation Générale à la Recherche Scientifique et Technique.]