Difference Limen for Duration of Acoustic Bursts, as Dependent on their Envelope Curves and Carrier Signals

Abstract

The just noticeable differences in duration of tone and noise bursts with rectangular, triangular and Gaussian envelopes were measured by the method of limits. The equivalent burst durations were 8, 24, 80, and 240 msec. As carrier signal of the pulses, either pure tone or noise of different spectral bandwidths (narrow band, 13-oct band, 1-oct band, and white noise) was used. The central frequency of the carrier signal was 250, 1000, or 4000 Hz. Six persons served as observers. Using the method of analysis of variance, the significance of each of the various signal and individual factors was determined. The most significant was the influence of the pulse duration. Second to it was the factor of individual differences between the subjects. On the third place was the influence of the carrier-signal central frequency. Neither the factor of the envelope curve nor of the carrier-signal frequency bandwidth exhibited any significant influence on the obtained data.