Perceptual segregation and pitch shifts of mistuned components in harmonic complexes and in regular inharmonic...

It is unclear whether the perceptual segregation of a mistuned harmonic from a periodic complex tone depends specifically on harmonic relations between the other components. A procedure used previously for harmonic complexes [W. M. Hartmann et al., J. Acoust. Soc. Am. 88, 1712-1724 (1990)] was adapted and extended to regular inharmonic complexes. On each trial, subjects heard a 12-component complex followed by a pure tone in a continuous loop. In experiment 1, a mistuning of +/- 4% was applied to one of the components 2-11. The complex was either harmonic, frequency shifted, or spectrally stretched. Subjects adjusted the pure tone to match the pitch of the mistuned component. Near matches were taken to indicate segregation, and were almost as frequent in the inharmonic conditions as in the harmonic case. Also, small but consistent mismatches, pitch shifts, were found in all conditions. These were similar in direction and size to earlier findings for harmonic complexes. Using a range of mistunings, experiment 2 showed that the segregation of components from regular inharmonic complexes could be sensitive to mistunings of 1.5% or less. These findings are consistent with the proposal that aspects of spectral regularity other than harmonic relations can also influence auditory grouping.