Stream segregation of narrow-band noise bursts

Normally hearing adults heard rapid alternations of a pair of band-limited noise bursts that had flat spectra (in terms of equal-loudness weighting of components) and sharp band edges. The bursts differed in center frequency (CF), but were matched on overall intensity, on bandwidth (BW) on a log-fre quency scale, and (roughly) on pitch strength. Listeners judged the ease wi th which the sequence could be held together perceptually in a single audit ory stream (vs. forming separate high and low streams). Involuntary segrega tion was examined as a function of the following measures of frequency sepa ration of the alternating noise bands: (1) the closest band edges, (2) the most remote band edges, (3) the CFs of the bands on a logarithmic scale, an d (4) the BWs. Segregation was best predicted from the separation of the tw o CFs on a log-frequency scale (very strong effect). Increasing the BWs of the two alternating bursts (the same size, in log frequency, for both bands ) also led to greater segregation (very weak effect).