The causes for the muffler attenuation trough was analyzed by the sound modal analysis and the sound pressure map analysis, and the improvement was put forward with the control measure of the long duct standing wave.

• 用声模态分析和声压分布图分析的综合方法分析了消声器产生消声低谷的原因，并利用长管道驻波的控制方法加以控制。