测量吸声系数的多传声器脉冲响应方法

An impulse response method with multi-microphones for investigating the absorption coefficient

脉冲响应法是测量吸声材料或吸声结构吸声系数的一种简单易行的方法 ,但使用单个传声器难以排除被测对象散射效应的影响 ,因此不能测量具有不平整表面构件的吸声系数。针对这一缺陷 ,本文提出了一种用多个传声器同时测量反射脉冲的实验分析技术 ,可以排除被测对象的反射与散射指向性对吸声系数分析的影响 ,故可用来测量具有不平整表面吸声结构在各种不同入射方向下的吸声系数。用该方法在半消声室内分析了一种表面呈锯齿形的声屏障斜入射吸声系数 ,结果表明本文提出方法可以满足工程应用的要求。

The Impulse Response Method (IRM) is widely used in investigating the absorption coefficient of some acoustical absorptive materials and structures. However, the IRM with single microphone usually fails to be applied to an un smooth absorptive surface, since the scattering effect interferes with the measurement. A multi microphone impulse response method is presented to study the absorption coefficient of the structures with various surfaces, by which the orientation effect of reflection and scattering can be eliminated in measuring absorption coefficient. The absorption coefficient of a sound barrier which absorptive surface consists of some triangle units is studied in multi microphone IRM in a semi anechoic chamber. The results show that the new technique can be applied to engineering.