900 m3混响室及其声源的声学特性的工程研究

摘要

Acoustic characteristics of the 900 m3 reverberation chamber and its sound sources are studied by experiment. The reverberation time, the acoustic power and the frequency characteristics of sound sources are measured and calculated, and the experimental results are analyzed. The reverberation time is calculated by suddenly cutting off the source according to the linear relation between the decrement of SPL and time. The spectrum shaping ability of the reverberation chamber under the reference sound source’s power spectrum is also discussed with respect to the reverberation time. The acoustic power is measured by the method of reverberation chamber and the method of approximate travelling wave field, respectively. The difference and the relation between the two methods are pointed out. The frequency characteristics of the acoustic generator driven by the white noise signal are evaluated by the method of the approximate travelling wave field. The reverberation chamber statistical frequency and the horn's acoustic loss are analyzed according to the experimental data, and the evaluation methods for the statistical frequency lower limit and the horn's acoustic loss are proposed.%文章对900 m3混响室及其声源的声学特性进行了实验研究，并用工程方法测试计算了混响时间、声功率以及声源的频率特性，对一些实验结果进行了探讨。根据声压级的衰变量与时间的线性关系，利用突然断开声源的方法计算了混响时间，并由混响时间讨论了参考声源功率谱下混响室谱成形能力问题。分别以混响室法和近似行波场法测算了声功率，指出两种方法的区别与联系。利用近似行波场法，以白噪声信号驱动音头评估了其频率特性。通过实验数据分别探讨了混响室统计频率与号筒声损耗问题，提出“统计频率下限”与号筒声损耗的估算方法。该项工作还有待深入研究。