Excitation-based and informational masking of a tonal signal ina four-tone masker&

摘要

This study examined contributions of peripheral excitation and informational masking to thevariability in masking effectiveness observed across samples of multi-tonal maskers. Detectionthresholds were measured for a 1000-Hz signal presented simultaneously with each of 25, four-tonemasker samples. Using a two-interval, forced-choice adaptive task, thresholds were measured witheach sample fixed throughout trial blocks for ten listeners. Average thresholds differed by as muchas 26 dB across samples. An ,excitation-based model of partial loudness [Moore, B. C. J. et al.(1997). J. Audio Eng. Soc. 45, 224-237] was used to predict thresholds. These predictionsaccounted for a significant portion of variance in the data of several listeners, but no relationbetween the model and data was observed for many listeners. Moreover, substantial individualdifferences, on the order of 41 dB, were observed for some maskers. The largest individualdifferences were found for maskers predicted to produce minimal excitation-based masking. Insubsequent conditions, one of five maskers was randomly presented in each interval. The differencein performance for samples with low versus high predicted thresholds was reduced in randomcompared to fixed conditions. These findings are consistent with a trading relation wherebyinformational masking is largest for conditions in which excitation-based masking is smallest.