Temporal Masking Effects: II. Critical Band Noise Masker

Masking of single, short test tone impulses by critical band noise masker impulses is measured. Simultaneous, forward (post) as well as backward (pre) masking are treated. The dependence of the masked threshold on the delay time between test tone impulse and masker impulse, test tone duration, test frequency, masker level and masker duration is investigated. This way, an atlas of temporal masking effects, elicited by a single critical band noise masker impulse, is produced. By means of these data, threshold values of test tone impulses masked by critical band noise of various temporal structures can be estimated.

In addition, some detailed results should be mentioned: The forward masking pattern of a critical band noise masker exhibits steeper slopes than both backward and simultaneous masking critical band rate pattern. Increasing the level of a critical band noise masker results in a flattening of the upper slope of its backward, simultaneous and forward masking pattern. For short delay time of test tone impulses, very short critical band noise masker impulses produce less backward as well as forward masking than longer maskers; simultaneous masking, however, is almost independent of masker duration. A transient masking pattern, i.e. masked thresholds as a function of both critical band rate and time, visualizes the influence of a single critical band noise masker impulse on single short test tone impulses. On the basis of results measured for single masker impulses, thresholds of test tone impulses, masked by bursts of a critical band noise masker are estimated. Predicted thresholds yield a rough approximation of data determined in control experiments.