Temporal integration of acoustic power was investigated 250, 1000, and 4000 cps over a range of signal durations from 1 or 2 cps to 256 msec. Signals were presented in a background of low‐level broad‐band white noise. Breaks in the function relating performance to signal duration (assuming that bandwidth equals 1/t) were used to infer critical bandwidth and difference limen for frequency. The critical‐bandwidth estimates are in agreement with most other data for the smaller set of critical‐bandwidth values sometimes called critical ratios. The difference‐limen estimates are in agreement with Shower and Biddulph's values obtained at a low sensation level.