Influence of Phase Coherence upon the Pitch of Complex, Periodic Sounds
J. C. R. Licklider · The Journal of the Acoustical Society of America · 1955
The aim of the paper is to resolve a conflict between observations. In the observations, the stimulus is a complex, periodic wave consisting only of high-frequency harmonics of a “missing” fundamental. Schouten found that a low subjective pitch was heard even when a search tone revealed no fundamental. And, recently, low pitch has been heard despite the presence of strong low-frequency masking noise. Yet, using five independently generated harmonics, Hoogland found that the low pitch emerged only when the sound intensity was high and nonlinear distortion produced an audible fundamental. The conflict is resolved by taking into account the phase pattern of the harmonics, which Hoogland did not control. When one adjusts the phases haphazardly, he often duplicates Hoogland's finding. But, when he adjusts them in such a way that all the harmonics come into their maxima at the same time and in sum produce an impulsive wave form, Schouten's low-pitched “residue” is clearly heard. Hoogland's observations thus fall neatly into line with composite place-periodicity theory.