Gap detection for pairs of noise bands: effects of stimulus level and frequency separation

Temporal gap detection was determined for single 20-Hz-wide noise bands having various center frequencies, and for simultaneously present pairs of noise bands where the spectral separation between center frequencies was varied. in most conditions, each noise band was present 30 dB above its detection threshold, but in some conditions, each noise band was presented 15 dB above its detection threshold. The results for single noise bands indicated that the gap threshold did not vary significantly across center frequency. Gap detection was significantly better for pairs of noise bands than for single noise bands. The improvement in gap detection when two noise bands were presented instead of one was greater at the 15-dB presentation level than at the 30-dB level. In the case where pairs of bands were presented, there was no effect of the spectral separation between bands, even though the spectral separation was varied over a range of 5 oct. Spectral integration for gap detection may be limited only by the audibility curve.