Department of Electrical Engineering, Acoustic Technology, Technical University of Denmark, Building 352, Kgs Lyngby DK-2800, Denmark.
J Acoust Soc Am. 2010 Jan;127(1):233-7. doi: 10.1121/1.3271034.
Reverberation rooms are often used for measuring the sound power emitted by sources of sound. At medium and high frequencies, where the modal overlap is high, a fairly simple model based on sums of waves from random directions having random phase relations gives good predictions of the ensemble statistics of measurements in such rooms. Below the Schroeder frequency, the relative variance is much larger, particularly if the source emits a pure-tone. The established theory for this frequency range is based on ensemble statistics of modal sums and requires knowledge of mode shapes and the distribution of modal frequencies. This paper extends the far simpler random wave theory to low frequencies. The two theories are compared, and their predictions are found to compare well with experimental and numerical results.
混响室常用于测量声源的声功率。在中频和高频范围内，模态重叠度较高，基于来自随机方向的波的叠加的相当简单的模型，以及随机相位关系，能够很好地预测此类房间中测量的总体统计数据。低于 Schroeder 频率时，相对方差要大得多，特别是如果声源发出纯音。该频率范围的现有理论基于模态和的总体统计数据，并且需要了解模态形状和模态频率的分布。本文将远更简单的随机波理论扩展到低频范围。对这两种理论进行了比较，发现它们的预测与实验和数值结果吻合良好。
