驻波管中声学材料隔声性能的修正计算方法

Algorithm for Modification of Measurement Data for Sound Transmission Loss of Acoustical Materials in Standing-wave Pipes

用驻波管四传声器法,分析了透射管中多次透射反射波对隔声量测试结果的影响,在考虑所有多次透射反射波的因素后推导了修正计算公式。通过对不同样品的测试,比较了考虑所有透射反射波的修正方法与仅考虑第一次透射反射波的修正方法的区别。实验结果表明:采用吸声性能优良的透射管声学末端,考虑一次透射反射波的修正方法可以得到正确的测量结果;而如果采用吸声性能较差的透射管声学末端,则应该考虑到所有高次透射反射波的影响。

Based on the four-microphone method of the standing-wave pipe,the effect of the multi- transmitted-andreflected waves in the transmission pipe on the sound transmission performance is discussed.The modification formula associated with the multi-transmitted-and-reflected waves is derived.By measuring several samples in the standing-wave pipe,the difference between the overall multi- transmitted-and-reflected modification and only the first transmitted-reflected modification is compared.Experimental results show that if the sound absorption performance of the acoustical terminal is perfect,the first transmitted-reflected modification is good enough to obtain the accurate sound transmission loss;while the sound absorption performance of the terminal is not perfect as the expected,the overall multi- transmitted- reflected modification should be taken into account.