Perceptual separation of simultaneous complex tones: The effect of slightly asynchronous onsets.

Onset asynchrony has been put forward as one of the relevant factors in auditory scene analysis [for references, see A. S. Bregman (MIT, Cambridge, 1990)]. In the present study this issue was investigated further using a new paradigm: Subjects were presented with two successive pairs of simultaneous complex tones and they had to decide whether the pairs contained tones with the same pitch. If this was the case they had to indicate which tones had been equal in pitch [the lower (LL), the higher (HH), the higher in the first pair and the lower in the second pair (HL), or vice versa (LH)]. In experiment 1, the frequency interval between L and H varied between 150 and 750 cents, and in the asynchronous conditions the onset of H was delayed by 20 ms. In experiment 2 various musical intervals were used that were either pure or slightly mistuned, and in the asynchronous conditions the onset of H preceded that of L by 25 ms. The results showed that for the degree of onset asynchrony investigated, no general evide...