Abstract:

Temporal integration of loudness for 1-kHz tones presented in quiet and under white-noise masking was measured for 5- and 200-ms tones using an adaptive 2I,2AFC procedure. Levels ranged from 5 to 90 dB SL. Results for six listeners with normal hearing show that the amount of temporal integration, defined as the level difference between equally loud 5- and 200-ms stimuli, varies nonmonotonically with level and is greatest at moderate levels. The average amount of temporal integration is about 15 dB near threshold, increases to a peak of 27 dB when the 5-ms tone is about 53 dB SPL, and decreases to about 15 dB near 100 dB SPL. For masker levels of 40, 60, and 80 dB SPL, the amount of temporal integration near masked threshold remains about 15 dB. The maximum amount of temporal integration decreases as masker level increases and occurs at progressively higher levels. At high levels, the amount of temporal integration is nearly the same as in quiet for all masker levels. These results are consistent with the loudness function being steeper near masked threshold than at the same SPLs in quiet. [Work supported by NIH-NIDCD R01DC02241.]