A power-law transformation predicting masking by sounds with complex spectra.

In a previous paper [R. Lutfi, J. Acoust. Soc. Am. 73, 262-267 (1983)], the following rule was proposed for predicting masking by pairs of simultaneous maskers; Xab = [XPa + XPb]1/P, where in units of power, Xa and Xb are the individual masking effects of the maskers, Xab is the combined effect, and 0.20 less than or equal to p less than or equal to 0.33. In this paper, the rule is used to predict the results of studies in the literature that have measured masking by sounds with various other complex spectra. In most of these studies, the individual maskers comprising the complex have nominally nonoverlapping power spectra. A single value of p = 0.33 yields predictions in good agreement with the data of these studies. For a study in which the component maskers overlap more appreciably, a larger value of p = 0.50 produces equally accurate predictions. The rule also predicts some general features of the results of studies in which the individual effects of the maskers in the complex are not known but can be estimated. It is suggested that the general applicability of the rule reflects a conjoint analysis by the auditory system of two or more waveform statistics.