Spectral locus and spectral spacing as determinants of the perceptual organization of complex tone sequences

Abstract

The perceptual organization of complex tone sequences into subsequences or “streams” was studied using spectral differences between tones as a basis for eliciting segregation. The absolute position of the spectra was varied to provide timbral differences between tones, while relative spacing between harmonics was varied to provide differences in pitch. These attributes were put in competition in rapidly occurring sequences of the form: TxPx TyPx TxPy TyPy, with the first pair of tones being assigned the pitch Px but different timbres Tx and Ty, and the second pair pitch Py, and similarly different timbres. Six listeners indicated their percept of such sequences as being groupings based on timbral similarity, pitch proximity, or ambiguous patterns not dominated by either cue. The results demonstrated that the stream segregation phenomenon may be based on relative changes in spectral locus and spectral spacing of the sequential tones, and imply that timbre and pitch can both serve as cues, with tradeoffs be...