A comparison of two methods for measuring the sound absorption coefficient using impedance tubes

The goal of this paper is to compare the two methods for measuring the sound absorption coefficient, the method that uses the standing wave ratio and the transfer function method, on several different materials. For this purpose, an impedance tube for the transfer-function method was designed and constructed. Measurements were made on mineral wool and foam of different thickness. At the end, measurement results for sound absorption coefficient for each material are shown and compared for two tubes.