Mossop J E, Culling J F
University Laboratory of Physiology, Oxford, United Kingdom.
J Acoust Soc Am. 1998 Sep;104(3 Pt 1):1574-9. doi: 10.1121/1.424369.
Two experiments explored the limits of listeners' abilities to interpret large interaural time delays (ITDs) in terms of laterality. In experiment 1, just-noticeable differences (jnd's) were measured, using an adaptive procedure, for various reference ITDs of Gaussian noise between 0 and 3000 microseconds. The jnd's increased gradually with reference ITD for reference ITDs between 0 microsecond and 700 microseconds, then rose sharply to plateau at much higher jnd's for the remainder of the standard ITDs tested (1000-3000 microseconds). The second experiment tested left/right discrimination of Gaussian noise that was interaurally delayed up to 10,000 microseconds, and high-pass filtered to cutoff frequencies between 0 Hz (broadband) and 3000 Hz. There was good discrimination (62%; significantly above chance, p < 0.05) for broadband and 500-Hz high-pass cutoff stimuli for all ITDs up to 10,000 microseconds, and for ITDs up to at least 3000 microseconds for higher high-pass cutoff frequencies. These results indicate that laterality cues are discriminable at much larger ITDs than are experienced in free-field listening, even in the absence of energy below 3 kHz.
两项实验探究了听众根据声音定位来解读较大双耳时间延迟（ITD）的能力极限。在实验1中，采用自适应程序测量了0至3000微秒之间高斯噪声的各种参考ITD的恰可察觉差异（jnd）。对于0微秒至700微秒之间的参考ITD，jnd随参考ITD逐渐增加，然后在测试的其余标准ITD（1000 - 3000微秒）中急剧上升至更高的jnd并趋于平稳。第二个实验测试了双耳延迟长达10000微秒且高通滤波至截止频率在0赫兹（宽带）至3000赫兹之间的高斯噪声的左右辨别能力。对于高达10000微秒的所有ITD，以及对于更高高通截止频率下至少高达3000微秒的ITD，宽带和500赫兹高通截止刺激均具有良好的辨别能力（62%；显著高于随机水平，p < 0.05）。这些结果表明，即使在3千赫兹以下没有能量的情况下，声音定位线索在比自由场聆听中所经历的大得多的ITD时仍可辨别。
