无顶空间内混响感特性的研究

A note on the reverberance in unroofed spaces

混响时间是反映时间域内声能衰变率的参量,它大体上可反映扩散空间内的主观混响感。但是,对于庭院等无顶空间而言是否适用,值得研究。因为在这些空间内,声能衰变过程中缺失了大量来自顶面的反射声,虽然混响时间可能变化不大,但会显著影响主观听觉上混响的感受。本文通过模拟声场的主观试听实验,发现反射声的方向性因素不可忽略,其对混响感有明显影响。由于混响时间是以单声道收录为界定的,因此,它不能充分反映无顶空间内的主观混响感。

The reverberation time in an enclosed space is denoted by the parameter of the sound energy decay rate in the time domain. It can be well represented the reverberance in a diffused sound field. But it is questionable for reverberance evaluation of an unroofed space such as a courtyard, with the absence of reflections from the top. Series of subjective comparison tests in our laboratory showed that the perceived reverberation might be also affected by tile spatial situation, especially noticeable and unneglectable in an unroofed space. Therefore the conventional reverberation time based on monaural receiver is not adequate for describing the reverberance in a courtyard space.