A study on acoustical design criteria of the balcony configuration in auditoria

阳台悬挑是经常设置在科洛尼亚。阳台下空间的截面形状是室内良好声学效果的重要因素之一。然而，悬挑下的声学特性尚未得到澄清，迄今为止还没有普遍接受的阳台配置的声学标准。本研究的目的是弄清阳台的形状与声学特性之间的关系，其次，通过心理声学实验考察了阳台的延迟时间（DELTAt）和上反射声的强度（L）的主观影响，因为阳台的存在影响了早期上反射声的结构，是造成观众厅阳台下音质缺陷的原因之一。模拟音乐声音与一个或两个反射被用作刺激。结果表明，声像的听觉尺寸随着DELTAt和L的减小而减小。接下来，将具有来自水平方向和来自上方的早期反射的模拟音乐声音用作刺激。结果表明，在横向能量分数一定的情况下，反射能量垂直分量越大，反射波的衰减越大。这些事实表明，缺乏来自主乐团上方天花板的早期反射是干扰阳台下良好声学效果的一个因素。

A balcony overhang is frequently set up in auditoria. The sectional shape of the under-balcony space is one of the most important factors for good acoustics in auditoria. The acoustical properties under the overhang, however, have not been clarified yet and there is so far no generally accepted criteria for acoustical of the balcony configuration. The object of this study is to make clear the relation between the shape of the balcony and the acoustical properties.As the second step, the subjective effects of the delay time(DELTAt) and the level(L) of reflections from upside is examined by psycho-acoustical experiments, because the structure of early reflections from upside, which is affected by the presence of a balcony, is regarded as one of the causes of acoustical defect under the balcony in auditorium. Simulated music sounds with a single or two reflections are uesd as stimuli. The results show that auditory size of sound image becomes smaller as DELTAt and L are smaller. Next, simulated music sound with early reflections both from horizontal directions and from upside are used as stimuli. The results show that envelopment becomes stroger as vertical component of reflected energy increases when lateral energy fraction is constant. These facts suggest that lack of early reflections from ceiling above main orchestra is a factor for disturbing good acoustics under the balcony.