Acoustic properties test of materials by the dual-microphones broadband impulse method

Paper presents the dual-microphones broadband impulse method to measure sound characteristics of acoustic materials. Based on the basic composition and process of sound pulse propagation in impedance tube, the pulse wave propagation model is respectively proposed, and sound pressure at any location of the tube can be expressed. Broadband impulse is generated in the tube and motivate the tube with a sample in the terminal. Sound pressure signals at any two location are acquired. Convert this two signals in time domain then the complex reflection coefficient and absorption coefficient in continuous band range are obtain Sound characteristics of the sponge sample and the porous glass sample have been tested by the dual-microphones broadband impulse method. Test results are coincided with which measured by impedance tube method. This method has improved the traditional impulse method without requiring impulse signal complete separation and has a value of application.