Journal of South China University of Technology (Natural Science Edition) ›› 2015, Vol. 43 ›› Issue (4): 126-132 137.doi: 10.3969/j.issn.1000-565X.2015.04.018

• Physics • Previous Articles     Next Articles

Analysis of Nonlinear Distortion in Impulse Response Measurement of Spherical Microphone Array

Liu Yu Xie Bo-sun Mai Hai-ming Chen Jia-yan   

  1. Research Institute of Acoustics,Department of Physics,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2014-08-21 Revised:2014-12-03 Online:2015-04-25 Published:2015-03-03
  • Contact: 谢菠荪(1960-),男,教授,主要从事电声学和心理声学等研究. E-mail:phbsxie@scut.edu.cn
  • About author:刘昱(1984-),男,博士生,主要从事电声系统与声频信号处理研究. E-mail: janworc@ gmail. com
  • Supported by:
    Supported by the National Natural Science Foundation of China(11174087,50938003)

Abstract: During the impulse response measurement of spherical microphone arrays,the scattering of the incident sound wave caused by the array geometry may change the harmonic proportion of signals recorded by the microphone.In this paper,two methods,one using the maximum length sequence and the other using the logarithmic sine sweep as the excitation source,were adopted to measure the impulse response,and the effect of nonlinear distortion on the measured results was analyzed. Moreover,a simulation was carried out for comparison. Simulated and measured re-sults indicate that (1) the proportion of harmonic distortion varies with the incident angle of sound source due to the scattering of incident sound wave on the spherical surface; (2) the microphone with a harmonic distortion array back onto the sound source slightly affects the output,while the microphone with a harmonic distortion array facing to the sound source greatly affects the output; and (3) in general,the measurement method based on the maximum length sequence is more sensitive to the nonlinear distortion of sound sources while the method based on the logarithmic sine sweep is more suitable for the impulse response measurement of spherical microphone arrays.

Key words: spherical microphone array, impulse response measurement, nonlinear distortion, maximum length se-quence, logarithmic sine sweep