Neff D L, Callaghan B P
Boys Town National Institute for Communication Disorders in Children, Omaha, Nebraska 68131.
J Acoust Soc Am. 1988 May;83(5):1833-8. doi: 10.1121/1.396518.
When more than one sinusoid is used as a masker, more masking is observed than would be predicted by a simple combination of their individual effects. This masking is dramatically increased when the masker components vary in frequency and intensity with each presentation. These studies manipulated several masker parameters under conditions of high masker uncertainty, examining the effect of excluding critical-band components, fixing or randomizing component amplitudes and frequencies, and narrowing the frequency range of the components. The signal was always a 200-ms, 1000-Hz sinusoid, presented simultaneously with the 200-ms masker. Removing critical-band components reduced the amount of masking, but considerable masking remained that appears to be nonperipheral in origin. Fixing masker frequencies across the two intervals of a trial greatly reduced the masking observed, whereas fixing masker amplitudes had no effect. Reducing the frequency range from 5000 to 2700 Hz generally increased the masking observed, but appeared to depend on other masker parameters. Summaries across ten listeners show individual differences that are resistant to extensive training. It is difficult to account for most of the masking observed in terms of masker energy falling near the region of the signal.
当使用多个正弦波作为掩蔽音时，观察到的掩蔽效应比其各自效应的简单组合所预测的要大。当每次呈现时掩蔽音成分的频率和强度发生变化时，这种掩蔽效应会显著增强。这些研究在掩蔽音高度不确定的条件下操纵了几个掩蔽音参数，研究了排除临界带成分、固定或随机化成分幅度和频率以及缩小成分频率范围的影响。信号始终是一个200毫秒、1000赫兹的正弦波，与200毫秒的掩蔽音同时呈现。去除临界带成分减少了掩蔽量，但仍存在相当多的掩蔽，其起源似乎是非外周性的。在一次试验的两个间隔中固定掩蔽音频率大大减少了观察到的掩蔽效应，而固定掩蔽音幅度则没有影响。将频率范围从5000赫兹降低到2700赫兹通常会增加观察到的掩蔽效应，但这似乎取决于其他掩蔽音参数。对十名听众的总结表明，个体差异对广泛训练具有抗性。很难根据落在信号区域附近的掩蔽音能量来解释观察到的大部分掩蔽效应。
