Bandwidth, apparent pitch, and frequency discrimination: Effects with complex harmonic tones

Abstract

Harmonically complex signals which are heard as having low pitch (< 0.3–0.5 kHz) yield superior pitch discrimination compared to equivalent‐pitch simple tones. On the other hand, narrow‐bandwidth complexes, heard to have pitch more nearly that of a carrier frequency rather than the spacing of sidebands, are discriminated nearly as well as pure tones of equivalent pitch. Frequency discrimination was measured using the PEST adaptive procedure and small logarithmic steps for harmonic spectra with center frequencies in the range 240–4800 Hz, and fundamental frequencies from 60–300 Hz, covering much of the range of musical and voice formants. These data, and a further experiment in which frequency discrimination was measured between wide bandwidth complexes when the signals were of unpredictable amplitude, are considered to rule against a recently published model from Horst et al. [J. Acoust. Soc. Am. 76, 1067–1075 (1984)] which proposed amplitude differences among specific components to be the basis of frequency discrimination. Instead a profile analysis based on activity in the frequency range of cochlear sensitivity is proposed. [Work supported by the Canadian National Science and Engineering Research Council.]