镜面与扩散反射界面球形空间语言清晰度比较

Comparison of speech intelligibility in spherical spaces of specularly and diffusely reflecting boundaries

定量分析扩散反射界面对球形空间内语言清晰度的改善作用.研究限定在几何声学的范畴内,无指向性点声源设在易引起球内声聚焦的典型位置球心上,界面吸声系数均匀分布.分别采用解析法与声学辐射度方法获得镜面与扩散反射界面球形空间的脉冲响应.计算与比较镜面与扩散反射界面球形空间内的脉冲响应和明晰度C50.为了衡量反射界面对球形空间内语言清晰度的改善效果,将球形空间与立方体空间的明晰度C50进行对比.结果表明,在镜面反射界面的球体中,C50值较低,而扩散反射界面能够在整体上提高C50值,尤其是在接近球心的声聚焦区域,但是界面反射模式引起的改善不如形体引起的改善有效.

The performance of diffusely reflecting boundary to improve the speech intelligibility in spherical spaces was quantitatively explored.The research was limited within geometrical acoustics.Omni-directional point source was set at the sphere center,which is a typical position to cause sound focusing easily in a sphere.The boundary sound absorption coefficient was uniformly distributed.By calculating the sound impulse responses and related parameters,comparisons were made between the sound fields under two boundary reflecting patterns in spheres.Analytical and acoustical radiosity methods were used for the cases of the two types of boundary respectively.Clarity （C50） was adopted as the objective parameter to assess the speech intelligibility.The results showed that C50 is low with specularly reflecting boundary,and diffusely reflecting boundary generally enhances C50,especially in the sound focusing area near the sphere center.However,the improvement caused by the boundary reflection pattern may be still inferior to that caused by room shape.