一种现场测量材料吸声特性的新方法

Method for measuring the absorption coefficient of sound absorbing materials in situ

现有的材料吸声系数测量方法主要有混响室法和驻波管法,都属于实验室测量方法,不适合现场测量。使用普通扬声器的反射法可以对材料的吸声特性进行现场测量,但是对材料尺寸和测试环境有较高的要求。本文利用参量阵非线性自解调可听声的高指向性和在阵长距离内的平面波特性,结合传递函数法,测量材料的吸声系数,并与传统驻波管测量结果进行了对比。结果表明在普通房间条件下,不需要驻波管,混响室等实验环境,即可对小尺寸的材料进行吸声系数的现场快速测量,具有较大的实用性。

The measurements of the absorption coefficient of sound absorbing materials are mainly using the standing wave tube or the reverberant room. Both of them are belong to laboratory methods, which are not suitable for mea- surement in situ. The normal loudspeaker reflection method can measure the absorption coefficients in situ. However, it has limitations on the size of the material and the measuring room. Based on the high directional property and the plan wave property of the self-demodulated sound from parametric array, under the excitation of sweep frequency sound wave, the absorption coefficients of the material are measured in free field and normal room. The testing results are compared to the standing wave tube method, which shows it is able to measure the absorption coefficients in situ rapidly without the standing wave tube or the reverberant room.