早期反射声时响度影响的实验研究

An experimental study of loudness evaluation of early reflection

大厅内产场强度的分布，对于稳态声源来说取决于各处的直达声和来自所有界面的反射声．但是对于语言和音乐等脉冲性质的声源，由于人耳的积分效应，只有直达声和早期反射声才对听众席上所感受到的响度起主要作用，因此作为音质评价参量，要考虑到声场的有效强度．于是在消声室内利用“干”语言录音进行一系列主观试听实验，以求了解短延时回声（早期反射声）对响度评价的作用．实验中由电声装置产生出含有原始声和单个或多个延时回声的声场．实验结果表明声场的感受响度与回声能量、入射角及其延迟时间分布有关．对多个短延时回声和超过３０－５０ｍｓ的单个回声来说，能量相加规律并不适用．在有些情况下实际感受的响度比能量相加规律要小得多．

The strength of a steady sound field in a hall depends on the direct sound leveland the level of reflections from all boundaries. But for speech and music having impulsivecharacteristics, only the direct sound and the early reflections are effective to the perceivedloudness to the listener according to the integrating ability of the ear. Therefore, a series ofsubjective comparison tests are carried out in an anechoic room, using recorded speech astesting material, and thus conducted to investigate the contribution of short delayed echoes(early reflections) to the loudness evalution. Sound fields consisting of primary sound anddelayed echoes, single or multiple, are produced by electroacoustic means. Results showthat the perceived loudness of the sound field is a function of the echo energy, angle of echoincidence and its temporal distribution. The law of the addition of energy to the echoes witha short delay is not applicable to multiple echoes as well as to a single echo after an intervalexceeding 30-50ms. In certain cases, they are much less than that can be expectedaccording to the said law.