Measurement and Analysis of Sound Absorption Coefficient by the Method of Reverberation Chamber and Impedance Tube

testing the sound absorption coefficient of three kinds of materials through the reverberation chamber method and impedance tube method, materials are sound-absorbing cotton, sponge and microporous sound-absorbing panels. The relationship between the sound absorption coefficient measured by two methods is analyzed and the following conclusions are drawn: random-incidence sound absorption coefficient and normal-incidence sound absorption coefficient of soundabsorbing cotton material changing with frequency in the similar trend, the peak value of sound absorption coefficient is in 800Hz, random-incidence sound absorption coefficient is larger than normal-incidence sound absorption coefficient; random- incidence sound absorption coefficient and normal-incidence sound absorption coefficient of sponge material changing with frequency in the similar trend, the peak value of sound absorption coefficient is in 800Hz, in 100Hz ~ 630Hz frequency band, random-incidence sound absorption coefficient is larger than normalincidence sound absorption coefficient, in 800Hz ~ 5000Hz frequency band, the difference between two kinds of sound absorption coefficient is very small; randomincidence sound absorption coefficient is larger than normal-incidence sound absorption coefficient of microporous sound-absorbing panels, the peak value of sound absorption coefficient is in 1250Hz, in 100Hz ~ 500Hz frequency band, two kinds of sound absorption coefficient are basically same, in 630Hz ~ 2500Hz frequency band, the curve trend of two kinds of sound absorption coefficient is basically the same, and random-incidence sound absorption coefficient is less than normal- incidence sound absorption coefficient. The results of the study provide a basis for the different test requirements and practical application of sound absorbing materials.