Absorption characteristics of an acoustic material at oblique incidence measured with the two-microphone technique
暂无分享,去创建一个
The two-microphone technique has been extended to the direct determination of the specific acoustic impedance, which is one of the basic quantities in acoustics. This method can be used to determine some acoustical characteristics of an absorbing sample (such as the reflection coefficient, characteristic acoustic impedance, and sound absorption coefficient) from the specific acoustic impedance. All measurements have been carried out in an anechoic room. It will be shown that the distance to the sample and the microphone spacing are critical parameters due to the standing waves in front of the sample. Some simple theoretical models are used to evaluate the accuracy of the results. At normal incidence the results are also compared with the results of Kundt tube measurements.
[1] J. Chung,et al. Cross‐spectral method of measuring acoustic intensity without error caused by instrument phase mismatch , 1978 .
[2] Jean François Allard,et al. Measurements of acoustic impedance in a free field with two microphones and a spectrum analyzer , 1985 .
[3] E. N. Bazley,et al. Acoustical properties of fibrous absorbent materials , 1970 .