窄脉冲声用于大样品的吸声测量

本文利用逆滤波器原理,在空间产生了波形可控、长度在毫秒量级的窄脉冲声信号,分别采用脉冲分离法和脉冲叠加法,对一种毛毡材料和三种不同厚度的海绵材料进行了吸声系数的测量。实验证明,基于窄脉冲声信号的吸声测量结果与ISO13472-1:2002中的MLS脉冲法及阻抗管的测量结果基本吻合。采用窄脉冲进行吸声测量,可以减少样品边缘和周围环境对测量信号的干扰,提高现场测量的准确性。

Sound absorption measurements of a large sample based on the short impulse method

Based on inverse filter principle,a controllable sound impulse with short duration (about 1ms) is generated and used as incident wave in the sound absorption measurements.A large sample of rock wool material and three sponge materials with various thicknesses are measured using the impulse subtraction method and the impulse superposition method, respectively.Compared to the standard MLS impulse method(ISO 13472-1:2002) and impedance tube method,good agreement of measuring results can be observed among these methods.It also indicates that the accuracy of the proposed method would be improved only if the shorter sound impulse is employed as an incident wave since there is less interruption from environment and sample edges during the measurements.