High-frequency complex pitch: a search for temporal cues and for a role of spectral indices

Harmonics in a complex tone are typically considered unresolved when they interact with neighboring harmonics in the cochlea and cannot be heard out separately. Recent studies have suggested that the low pitch evoked by unresolved high-frequency harmonics may be coded via temporal fine-structure cues. However, these conclusions rely on the assumptions that combination tones were properly masked and that the ability of listeners to hear out individual partials provides an adequate measure of resolvability. Those assumptions were tested by measuring the audibility of combination tones and their effects on pitch matches, the effects of relative component phases and of dichotic presentation, and listeners' ability to hear out individual partials. The results confirmed that combination tones affected pitch, but pitch remained salient when they were masked. The lack of dependence of pitch on relative component phases or dichotic presentation provided no evidence in favor of temporal cues. Moreover, similar trends were observed between pitch salience and the listeners' ability to hear out individual partials. The results are consistent both with the use of place information and with a temporal code based on the combination of information across auditory channels.