Audible Threshold of Early Reflections with Different Orientations and Delays
Audible Threshold of Early Reflections with Different Orientations and Delays
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DOI：
10.32604/sv.2018.03900
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Xiaoli Zhong;W. Guo;Jie Wang
中科院分区：
文献类型：
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作者：
Xiaoli Zhong;W. Guo;Jie Wang
早期反射是封闭声场中的重要组成部分。由于优先效应的存在，早期反射可能不是声源定位的主导因素，但对声源的空间位置、响度、音色等仍有明显的影响。目前，关于早期反射听阈的研究较少，缺乏普遍的定量结果。本文采用简化的声场模型，在八个入射角和五个时间延迟组合的实验条件下，研究了早期反射的可听阈值。由于其效率和鲁棒性，采用了三间隔三选择强迫选择（3 I-3AFC）的三下一上自适应策略。结果表明：（1）早期反射声的听阈随着相对于直达声的时延的增加而单调下降。（2）当直达声与反射声位于同一半平面时，随着直达声与反射声夹角的增大，早期反射声的可听阈值降低。（3）不同个体的早期反射阈值存在较大的差异，尤其是在早期反射相对于直达声有较大的角度偏差和时间延迟时。
Early reflection is an important component in an enclosed sound field. Due to the precedence effect, the early reflection may not be the dominant factor in sound source localization; however, it still has obvious influences on spatial position, loudness, timbre, and etc. Till now, there have sparse studies on evaluation of the audible threshold of early reflections with lacking of general and quantitative results. This work investigated the audible threshold of early reflection with a simplified sound field model under various experimental conditions including the combination of eight incidence angles and five time delays. Three-down-one-up adaptive strategy with three-interval three-alternative forced-choice (3I-3AFC) paradigm was used due to its efficiency and robustness. Results indicate that (1) the audible threshold of early reflections decreases monotonically with increasing time delay relative to the direct sound. Furthermore, a linear equation between early reflection threshold and time delay is established with correlation coefficient higher than 0.9; (2) When the direct sound and the reflection locate in the same half-plane, the audible threshold of early reflections decreases with increasing angle deviation between the direct sound and the reflection. Moreover, a front-back symmetry of early reflection threshold is observed for stimuli below 5 kHz; (3) Considerable variations in early reflection threshold are found among individuals, especially at large angle deviation and time delay of early reflections relative to the direct sound.