混响室中混响时间测量偏差的研究

Research on the fluctuation of reverberation time measurements in reverberation room

在混响室中测量吸声材料的吸声系数时,需要进行混响室中有吸声材料时混响时间的测量和没有吸声材料时混响时间的测量,两者的可重复性和可靠性直接影响到所测材料吸声系数的准确度。通过统计声学和波动声学的基本原理对混响室中混响时间测量的空间偏差和重复偏差产生的原因进行了分析,并且在多组不同的实验条件下,在南京大学混响室中实测了空场时的混响时间和有吸声材料时的混响时间。通过比较、分析混响时间测量结果的空间偏差和重复偏差,总结出了混响室中混响时间测量的空间偏差和重复偏差较小的测量条件。

When measuring the absorption coefficient of a certain material in reverberation room,the reverberation times of the reverberation room both with and without material need to be measured.The repeatability and reliability of the two measurements in reverberation room affect the accuracy of the measured absorption coefficient of this material.The cause of the spatial variance and ensemble variance of the reverberation time measurement is analyzed with the principles of statistic acoustics and wave acoustics.The reverberation times in the reverberation room of Nanjing university have been measured under different conditions,and the results are compared and analyzed.In the end the measurement condition under which we can get less spatial variance and ensemble variance of the reverberation time measurement is concluded.