Dye R H
Parmly Hearing Institute, Loyola University, Chicago, Illinois 60626.
J Acoust Soc Am. 1990 Nov;88(5):2159-70. doi: 10.1121/1.400113.
Three experiments were carried out that employed low-frequency tone complexes with interaural delays that varied across the frequency domain. In the first experiment, threshold interaural delays were measured for three-tone complexes for which one, two, or all three components were delayed. The center frequency was 750 Hz and the frequency spacing (delta f) between components was 20, 50, 100, 250, or 450 Hz. For all delta f's, the presence of two diotic components elevated the threshold interaural delays obtained for the third component relative to that obtained for a pure tone of the same frequency. In the second experiment, observers made left-right judgments regarding the direction of movement of signals for which two components were delayed by 25 microseconds to the left ear during one interval and to the right ear during the other interval, while a third component of a variable time difference was delayed to the opposite side as the tone pair. Subjects reported single intracranial images during each interval, and the data showed that interaural delays of one component to one ear could be offset by interaural delays of the other two components to the other ear. In the final experiment, threshold interaural delays were measured for five-tone complexes in which one, two, three, four, or five components were delayed. The center frequency was 750 Hz and delta f was fixed at 100 Hz. Thresholds decreased in a linear fashion as the number of delayed components increased, falling by about a factor of 5 as the number of delayed components went from one to five. These results are consistent with spectrally synthetic binaural processing, with the lateral position of intracranial images determined by a combination of interaural information across the spectrum. These effects could be brought about by a linear combination of the outputs of frequency-specific cross-correlation networks or by a wideband cross correlation of the signals at the two ears.
进行了三项实验，这些实验采用了具有跨频域变化的耳间延迟的低频音调复合体。在第一个实验中，测量了三音复合体的阈下耳间延迟，其中一个、两个或所有三个成分都被延迟。中心频率为750赫兹，成分之间的频率间隔（δf）为20、50、100、250或450赫兹。对于所有的δf，相对于相同频率的纯音所获得的阈下耳间延迟，两个双耳成分的存在提高了第三个成分所获得的阈下耳间延迟。在第二个实验中，观察者对信号的运动方向进行左右判断，其中两个成分在一个间隔内左耳延迟25微秒，在另一个间隔内右耳延迟，而第三个具有可变时间差的成分延迟到与音对相反的一侧。受试者在每个间隔期间报告单个颅内图像，数据表明一个成分到一只耳朵的耳间延迟可以被其他两个成分到另一只耳朵的耳间延迟抵消。在最后一个实验中，测量了五音复合体的阈下耳间延迟，其中一个、两个、三个、四个或五个成分被延迟。中心频率为750赫兹，δf固定为100赫兹。随着延迟成分数量的增加，阈值呈线性下降，当延迟成分数量从一个增加到五个时，下降了约5倍。这些结果与频谱合成双耳处理一致，颅内图像的横向位置由整个频谱上的耳间信息组合决定。这些效应可能由频率特异性互相关网络的输出的线性组合或两只耳朵处信号的宽带互相关引起。
