For abruptly gated sound, interaural time difference (ITD) cues at onset carry greater perceptual weight than those following. This research explored how envelope shape influences such carrier ITD weighting. Experiment 1 assessed the perceived lateralization of a tonal binaural beat that transitioned through ITD (diotic envelope, mean carrier frequency of 500 Hz). Listeners' left/right lateralization judgments were compared to those for static-ITD tones. For an 8 Hz sinusoidally amplitude-modulated envelope, ITD cues 24 ms after onset well-predicted reported sidedness. For an equivalent-duration “abrupt” envelope, which was unmodulated besides 20-ms onset/offset ramps, reported sidedness corresponded to ITDs near onset (e.g., 6 ms). However, unlike for sinusoidal amplitude modulation, ITDs toward offset seemingly also influenced perceived sidedness. Experiment 2 adjusted the duration of the offset ramp (25–75 ms) and found evidence for such offset weighting only for the most abrupt ramp tested. In experiment 3, an ITD was imposed on a brief segment of otherwise diotic filtered noise. Listeners discriminated right- from left-leading ITDs. In sinusoidal amplitude modulation, thresholds were lowest when the ITD segment occurred during rising amplitude. For the abrupt envelope, the lowest thresholds were observed when the segment occurred at either onset or offset. These experiments demonstrate the influence of envelope profile on carrier ITD sensitivity.

中文翻译：

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包络形状对调幅低频声音偏侧化的影响

对于突然门控的声音，开始时的耳间时间差 (ITD) 线索比后面的线索具有更大的感知权重。本研究探讨了包络形状如何影响此类载波 ITD 加权。实验 1 评估了通过 ITD（双耳包络，平均载波频率为 500 Hz）过渡的音调双耳节拍的感知偏侧化。将听者的左/右偏侧判断与静态 ITD 音调进行比较。对于 8 Hz 正弦调幅包络，ITD 在发病后 24 ms 提示良好预测的报告边性。对于等效持续时间的“突然”包络，除了 20 毫秒的起始/偏移斜坡之外未调制，报告的边性对应于接近起始的 ITD（例如，6 毫秒）。然而，与正弦调幅不同的是，对抵消的 ITD 似乎也影响了感知的片面性。实验 2 调整了偏移斜坡的持续时间（25-75 毫秒），并发现这种偏移加权仅适用于测试的最突然斜坡的证据。在实验 3 中，ITD 被强加到一个简短的片段上，否则会被过滤掉。听众区分右前和左前的 ITD。在正弦幅度调制中，当 ITD 段出现在幅度上升期间时，阈值最低。对于突然包络，当该段发生在起始或偏移时观察到最低阈值。这些实验证明了包络轮廓对载波 ITD 灵敏度的影响。一个 ITD 被强加在一个简短的片段上，否则会被过滤掉。听众区分右前和左前的 ITD。在正弦幅度调制中，当 ITD 段出现在幅度上升期间时，阈值最低。对于突然包络，当该段发生在起始或偏移时观察到最低阈值。这些实验证明了包络轮廓对载波 ITD 灵敏度的影响。一个 ITD 被强加在一个简短的片段上，否则会被过滤掉。听众区分右前和左前的 ITD。在正弦幅度调制中，当 ITD 段出现在幅度上升期间时，阈值最低。对于突然包络，当该段发生在起始或偏移时观察到最低阈值。这些实验证明了包络轮廓对载波 ITD 灵敏度的影响。