Danish Fundamental Metrology, Danish Primary Laboratory of Acoustics, Matematiktorvet 307, 2800 Kongens Lyngby, Denmark.
J Acoust Soc Am. 2010 Apr;127(4):2290-4. doi: 10.1121/1.3353093.
The relation between the diffuse-field response and the radiation impedance of a microphone has been investigated. Such a relation can be derived from classical theory. The practical measurement of the radiation impedance requires (a) measuring the volume velocity of the membrane of the microphone and (b) measuring the pressure on the membrane of the microphone. The first measurement is carried out by means of laser vibrometry. The second measurement cannot be implemented in practice. However, the pressure on the membrane can be calculated numerically by means of the boundary element method. In this way, a hybrid estimate of the radiation impedance is obtained. The resulting estimate of the diffuse-field response is compared with experimental estimates of the diffuse-field response determined using reciprocity and the random-incidence method. The different estimates are in good agreement at frequencies below the resonance frequency of the microphone. Although the method may not be of great practical utility, it provides a useful validation of the estimates obtained by other means.
研究了传声器的扩散场响应与辐射阻抗之间的关系。这种关系可以从经典理论中推导出。辐射阻抗的实际测量需要（a）测量传声器膜片的体积速度，以及（b）测量传声器膜片上的压力。第一项测量是通过激光测振仪进行的。第二项测量在实践中无法实现。然而，通过边界元法可以对膜片上的压力进行数值计算。通过这种方式，可以获得辐射阻抗的混合估计值。得到的扩散场响应的估计值与使用互易法和随机入射法确定的扩散场响应的实验估计值进行了比较。在低于传声器共振频率的频率下，不同的估计值吻合得很好。尽管该方法可能没有很大的实际用途，但它为通过其他方法获得的估计值提供了有用的验证。
