Device for measuring sound absorption coefficient of acoustic material by use of pulse method and measuring method

Abstract

The invention provides a device for measuring the sound absorption coefficient of an acoustic material by use of a pulse method and a measuring method. The device comprises a sound tube, a pulse sound source, a microphone, a power amplifier, a signal conditioner, an adapter and a data acquisition device, wherein the sound tube is formed by coaxially and fixedly connecting a large-diameter cylindrical tube, a conical tube and a small-diameter cylindrical tube in sequence; two through holes vertical to the central axis of the small-diameter cylindrical tube and used for mounting the microphone are formed on the side wall of the small-diameter cylindrical tube; the pulse sound source is mounted in the large-diameter cylindrical tube; and the outer end of the small-diameter cylindrical tube is in threaded connection with a rear cover. The measuring method comprises the following steps of: obtaining a frequency response function of the whole measuring system; obtaining an excitation signal spectrum of the required pulse sound source; and exciting the pulse sound source by use of the excitation signal of the required pulse sound source and measuring to obtain the sound absorption coefficient of a to-be-measured sample. The device and method provided by the invention avoid secondary error caused by decomposing a sound field in a frequency domain in the traditional method, and also overcome the problem of phase matching in the traditional multi-microphone method.

Description

technical field [0001] The invention relates to the technical field of acoustic material testing, in particular to a measuring method for measuring the sound absorption coefficient of acoustic materials by using a pulse method. Background technique [0002] In the field of acoustic tube acoustic testing, the current measurement technology for the sound absorption coefficient of acoustic materials is based on the transfer function method to measure in the impedance tube. For example, the corresponding value is obtained by measuring the transfer function at different positions in the acoustic tube. The main problem is the phase matching between the multiple microphones. Two microphones can be used to exchange the measurement transfer function to eliminate the mismatch between the two microphones, and the single-microphone method can be used for sequential measurement, so there is no problem of phase and amplitude mismatch, but it will increase the test time and make the test w...

AI Technical Summary

Problems solved by technology

The transfer function can be measured by exchanging two microphones to eliminate the mismatch between the two microphones, and the single-microphone method can also be used for sequential measurement, so there will be no problem of phase and amplitude mismatch, but it will increase the test time and make the test work easier. cumbersome

Images