Bistafa S R, Bradley J S
Institute for Research in Construction-Acoustics, National Research Council Canada, Ottawa, Ontario.
J Acoust Soc Am. 2000 Oct;108(4):1721-31. doi: 10.1121/1.1310191.
By varying the sound-absorption treatments in a simulated classroom, experimental results were compared with analytical and computer predictions of reverberation time. Analytical predictions were made with different absorption exponents, which are the result of different weighting procedures involving room surface areas and the sound-absorption coefficients. Sound scattering was found to influence measured reverberation times. With the amount of sound scattering provided, more accurate analytical predictions were obtained with absorption exponents that give reverberation times longer than those obtained with the Sabine absorption exponent, which consistently underpredicted reverberation times. However, none of the absorption exponents could be singled out as more adequate because of similar average accuracy. Computer predictions of reverberation time were accomplished with two commercially available ray-based programs, RAYNOISE 3.0 and ODEON 2.6, with specular and calibrated diffuse reflection procedures. Neither type of procedure, in either program, was more accurate than the best analytical predictions. With RAYNOISE, neither the specular nor the calibrated diffuse reflection procedure could be singled out as more adequate. For ODEON, the calibrated diffuse reflection procedure gave consistently more accurate predictions than its specular reflection procedure, with the best accuracy of the computer predictions.
通过在模拟教室中改变吸声处理方式，将实验结果与混响时间的分析预测和计算机预测进行了比较。分析预测采用了不同的吸收指数，这些指数是涉及房间表面积和声吸收系数的不同加权程序的结果。发现声散射会影响测量的混响时间。在所提供的声散射量下，使用比赛宾吸收指数得出的混响时间更长的吸收指数可获得更准确的分析预测，而赛宾吸收指数一直低估混响时间。然而，由于平均精度相似，没有一个吸收指数能被单独挑出来认为更合适。混响时间的计算机预测是使用两个市售的基于射线的程序RAYNOISE 3.0和ODEON 2.6完成的，采用了镜面反射和校准漫反射程序。在这两个程序中，这两种程序类型都不比最佳分析预测更准确。对于RAYNOISE，镜面反射程序和校准漫反射程序都不能被单独挑出来认为更合适。对于ODEON，校准漫反射程序给出的预测始终比其镜面反射程序更准确，具有计算机预测中的最佳精度。
