Effects of resolved and unresolved harmonics in the perception of multiple pitches

Abstract

The mechanisms underlying pitch perception have been studied for several decades. Most studies have concentrated on the pitch of single sounds, some have investigated the pitch of two simultaneously presented sounds, but few if any have investigated pitch perception with three or more simultaneous pitches. In contrast, in music it is rule, rather than the exception, that we are presented with multiple pitches. Here, pitch perception was studied with three simultaneously presented harmonic complexes, filtered into a single bandpass region to control the extent to which harmonics from each of the three tones were spectrally resolved. The tones comprised the three possible inversions of the major or minor triad, and the listener’s task was to discriminate between major and minor. Preliminary data suggest that subjects who could reliably discriminate major and minor triads in a pure tone training task were also capable of this discrimination when tone complexes were filtered such that the combination of harmonic components should have been unresolved on the cochlea. This finding suggests resolved harmonics may not be necessary to extract the pitch from multiple complex tones. Predictions from various spectral and temporal models of pitch were compared with the results. [Work supported by NIH grant R01DC05216.]