The echo threshold (ET), defined as the critical time delay from perceiving a single fused sound image to two spatially separated sound images in the presence of delayed stimuli, is the upper limit of precedence effect. In the ET measurements using headphones, the interaural time difference (ITD) stimuli presentation method is often employed. However, considering AR/VR scenarios, the virtual auditory space (VAS) stimuli presentation method may be more reasonable because it conveys more spatial (localization) cues. This study examines the ET difference between the VAS and ITD presentation methods using headphones, and further explores the effect of localization cues on the ET. Experiments are conducted using the classical lead-lag paradigm and 4 types of stimulus. The results show that the ETs of both methods are not significantly different for the 1-ms noise burst stimulus, whereas for the three long-duration realistic stimuli, the ITD method gives significantly higher ETs than the VAS method. Compared with VAS method, the disagreement between ITD and the interaural level difference in the ITD method leads to a smaller lead-lag spatial separation and a greater single sound image width. These two factors may explain the larger ET in the ITD method, as well as the effect of the latter factor can be understood from the viewpoint of signal detection theory.

中文翻译：

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基于耳机的刺激呈现方法对回声阈值的影响

回声阈值（ET）定义为在存在延迟刺激的情况下从感知单个融合声像到两个空间分离的声像的临界时间延迟，是优先效应的上限。在使用耳机的 ET 测量中，经常采用耳间时间差（ITD）刺激呈现方法。然而，考虑到 AR/VR 场景，虚拟听觉空间（VAS）刺激呈现方法可能更合理，因为它传达了更多的空间（定位）线索。本研究考察了使用耳机的 VAS 和 ITD 演示方法之间的 ET 差异，并进一步探讨了本地化线索对 ET 的影响。实验使用经典的超前-滞后范例和 4 种类型的刺激进行。结果表明，对于 1 ms 噪声突发刺激，两种方法的 ET 没有显着差异，而对于三种长持续时间的现实刺激，ITD 方法给出的 ET 显着高于 VAS 方法。与VAS方法相比，ITD方法中ITD与耳间电平差的不一致导致了更小的超前滞后空间分离和更大的单声图像宽度。这两个因素可以解释ITD方法中较大的ET，并且后一个因素的影响可以从信号检测理论的角度来理解。