全数字化小尺度封闭空间音质评价研究(二)客观评价方法

Research of Full Digital Sound Quality Evaluation in Small Enclosures PartⅡ:Objective Evaluation

在小尺度封闭空间内,声波低频成分的波长与空间尺寸相当,声音在传播过程中所发生的散射、衍射等波动现象不容忽视。目前以几何声学为理论基础的音质评价方法无法直接用于小尺度封闭空间中,需要发展以波动声学为理论基础的音质评价方法。以室内声场有源Helmholtz方程及其相应边界方程为基础,分别研究基于计算机辅助的全数字化小尺度封闭空间主观音质评价及客观音质评价方法。这一部分着重研究小尺度封闭空间内的客观音质评价。首先,在声有限元模型基础上,给出了声能密度及声能的有限元计算模型。并以此为基础,提出了混响时间、清晰度和明晰度、中心时间等重要音质参数的计算模型。最后,计算了一矩形封闭空间内的声能密度及混响时间,通过与实验结果进行比较,验证了这一方法是有效可行的。

This is the second part of the paper on full digital sound quality assessment in small enclosures.Objective sound quality assessment will be studied.Firstly,based on sound Finite Element Method(FEM)model,FEM model for calculating energy density and acoustic energy is built.Secondly,different models for calculating reverberation time,def-inition,clarity index and center time are given based on that.Finally,as an example,sound energy density and rever-beration time in a rectangle cavity are calculated and compared with those given by experiment respectively.The results show that the method is effective and feasible.