声管中隔声量测试的脉冲声法

Measurement of Sound Transmission Loss in an Acoustic Pipe Using Pulse Method

文章提出了利用单传声器在声管中进行隔声量测试的脉冲声方法。现有的阻抗管隔声测量方法均采用多传声器法。利用自行开发的声管吸声/隔声测试系统,通过对系统传递特性的测量,采用逆滤波器原理,消除了声管端口的反射并能够对扬声器频响在高低频进行补偿,最终在声管中获得单一的Butterworth宽频脉冲。将其作为入射波对某型号发动机声学材料的隔声量进行了测试,并和声望SW466阻抗管测试结果进行了对比。在500~4 500 Hz的频率范围内,二者吻合较好。该系统只需要单传声器进行2次测量,测量装置简单,而且测量的重复性好,可以作为一种有效的隔声测量方法。

The sound transmission loss measurement is usually executed by multi-microphone method in an impedance tube.A single broadband frequency Butterworth sound pulse is generated in an acoustic pipe by measuring the system transfer function and using inverse filter principle which can eliminate reflections from pipe exit and complement the frequency response of loudspeaker at low and high frequencies.The sound transmission loss of a kind of material is measured using the butterworth pulse as incident wave.Through comparison with the SW466 impedance tube results,it is found that the results obtained from the proposed method agree well with those from the standard method in frequency range from 500 to 4500Hz.Since only single microphone is needed and measurement repeatability is good,the proposed method is believable as an effective method for transmission loss measurement.