INVESTIGATION OF SOUND ABSORPTION COEFFICIENT BY DECAY OF STANDING WAVES IN THE IMPEDANCE TUBE


Determination of absorption coefficient in materials, in a condition of wide consumption, is a very difficult problem and in majority cases may be said it is impossible because of requirements of special laboratory, apparatuses and measured devices. Moreover, by the existing methods, the accuracy of measured coefficient depends on a method of measuring and fixing of a sample. The wide spreading of modern digital technique and software give the ability that the material acoustical features, in particular the sound absorption coefficient were determined in a wide consumption. According to the presented method, the sound absorption coefficient is measured directly i.e. by the relation of reflected and incident waves but not by bypass ways as it is done in the present, so the presented method ensures more exactness and stability of measuring.