Effects of asynchrony and ear of presentation on the pitch of mistuned partials in harmonic and frequency-shifted complex tones

When a partial of a periodic complex is mistuned, its change in pitch is gr eater than expected. Two experiments examined whether these partial-pitch s hifts are related to the computation of global pitch. In experiment I, stim uli were either harmonic or frequency-shifted (25% of F0) complexes. One pa rtial was mistuned by +/-4% and played with leading and lagging portions of 500 ms each, relative to the other components (1 s), in both monaural and dichotic contexts. Subjects indicated whether the mistuned partial was high er or lower in pitch when concurrent with the other components. Responses w ere positively correlated with the direction of mistuning in all conditions . In experiment 2, stimuli from each condition were compared with synchrono us equivalents. Subjects matched a pure tone to the pitch of the mistuned p artial (component 4). The results showed that partial-pitch shifts are not reduced in size by asynchrony. Similar asynchronies are known to produce a near-exclusion of a mistuned partial from the global-pitch computation. Thi s mismatch indicates that global and partial pitch are derived from differe nt processes. The similarity of the partial-pitch shifts observed for harmo nic and frequency-shifted stimuli suggests that they arise from a grouping mechanism that is sensitive to spectral regularity. (C) 2001 Acoustical Soc iety of America.