两端开口空间的声场研究

研究了两端开口空间中声压分布同封闭空间和长空间中的不同,比较传统赛宾公式、改进赛宾公式和声线法对这种空间的估计准确度,同时对其中出现非指数衰变曲线进行讨论,分析其产生的原因、影响因素和规律。文中使用声线法进行数值计算,并且通过实验来和数值结果比较,验证结论。研究表明:两端开口空间中的稳态声压分布与封闭空间和长空间明显不同,混响时间的计算不能再使用传统赛宾公式,声线追踪法无法完全准确地估计稳态声压;其中出现非指数衰变曲线的原因经分析为空间内各不同活跃度的小区域之间的声能量耦合造成,而能否被观察到取决于能否满足耦合空间理论中对于双斜率衰变曲线出现的要求,直观上只要观察点和声源距离相差不远,并且不都在空间中央便可观察到明显的双斜率衰变曲线。 

A study on the sound field in a vault with two open ends

This article studies the difference of sound pressure distribution in a vault with two open ends and in enclosure and long space,by comparing classic Sabine Formula,modified Sabine Formula and ray tracing method's accurate estimation on this kind of space,and at the same time discusses the non-exponential decay curve occurred in that,analyzes the reason of its occurrence,elements and rules of why it has been influenced.Ray tracing method has been used to conduct numerical simulation in this article and results of experiments have been compared with the numerical results to verify the conclusion.The steady sound pressure distribution in the vault with open ends is obviously different from that in enclosure and long space.The classic Sabine Formula can not be used to calculate reverberation time and the estimation of steady sound pressure by ray tracing method is trivial.As for the reason of the occurrence of non-exponential decay curve,it is because the coupling of sound energy between small zones of different "live" degrees within the space and it also depends on if requirements of double-sloped decay curve in coupled volumes theory can be fulfilled or not.If the distance between the observation spot and sound source is not big and both of them are not in the middle of the space,then double-sloped decay curve could be observed very obviously.