厅堂音质中的响度评价

Criterion of the overall strength in auditorium acoustics

厅堂音质评价的各项指标中，响度是最重要和最基本的内容之一。但由于长期来缺乏合适的参量，因此迄今无法在完工后的厅堂中去测量这项指标，当然也难以在设计阶段对此参量进行估算．不少人常把仅仅适用于稳态声源和混响场的声场估算法（即以直达声加上混响声）作为厅堂内各处总声强的评价，无论从音质设计和现场测量来看，显然很不合适。近年Ｌｅｈｍａｎｎ提出以声强指数Ｇ（Ｓｔａｒｋｅｍａｓｓ）（ｄＢ）作为评价参量是一个好的建议。但根据我们的研究结果来看，鉴于早期反射声对响度起主导作用，因此厅堂内各处的声强指数应取５０ｍｓ（语言）和８０ｍｓ（音乐）的早期反射声积分值更符合实际，。以代替ｔ从０积分到∞的评价方法。因此Ｇ（５０ｍｓ）和Ｇ（８０ｍｓ）将分别用于评价厅堂内对语言和音乐的响度评价参量。

Among all the criteria used for assessing the acoustical quality of an auditorium, the overallstrength, or the loudness, is one of the most essential attributes. But little had been done on this criterion inthe past owing to the lack of appropriate measure to describe and quantify such a criterion, therefore it ishard to predict the overall strength in a hall during the design stage, and also cannot check it when the hall iscompleted. A new measure so called strength index G (Starkemsas) developed by Lehmann gives a good proposal to quantify the overall strength in an auditorium. He found that the impression of the strength is notproduced only by the direct Sound,nor by the early 'useful' sound, but all of the reflechons arriving at the listeneds position. But our experience, also from other authors, shows the direct sound and early reflections playing the main role in determination of loudness impression due to the 'licit of Perceptibility' or 'the inertia of hearing'. Therefore it is more reasonable to set an integrating time of the useful reflections for determining the strength index, say 50ms for speech and 80ms for music. The strength index G hence should be written as G50 for speech and G 80 for music.