Judgments of sound volume: effects of signal duration, level, and interaural characteristics on the perceived extensity of broadband noise.

Abstract

While auditory stimuli are often described in terms of their apparent extensity, such descriptions have usually not been collected systematically. Moreover, the few deliberate attempts to evaluate image size have rarely gone beyond the classic parameters of stimulus frequency and intensity. In the present study a direct magnitude estimation procedure was employed. Seventeen subjects numerically estimated the apparent size of images produced by broadband noise stimuli. Under earphone listening conditions, signals were presented either dichotically (uncorrelated noise), diotically (correlated noise), or monaurally (noise led to a single earphone). The signals in each of these modes varied in duration (100, 300, 1000, and 3000 msec) and intensity level (60, 75, and 90 dB A weighted). Size estimates were plotted as power functions and analyzed with a repeated measures design analysis of variance. Consistent with previous research, the main effects of duration and intensity were both highly significant (p less than 0.001). In addition, a highly significant effect for mode of presentation was found (p less than 0.001). Across conditions, dichotic stimulation produced the largest images and monaural stimulation the smallest (about half the size of the diotic images). This last result is the first quantification of previous anecdotal observations. General implications of these results were discussed.