Sound Transmission Loss Measurement for Sound Isolation Sheets by Two-Microphone Impedance Tube Method

두 개의 마이크로폰의 부착된 임피던스관법을 이용한 차음시트의 음향투과손실 측정

  • Lee, Dong-Hoon (Department of Mechanical Engineering, Seoul National University of Technology) ;
  • Yong, Ho-Taek (Department of Mechanical Engineering, Seoul National University of Technology) ;
  • Lee, Seung (Department of Mechanical Engineering, Graduate School of Industry and Engineering, Seoul National University of Technology)
  • 이동훈 (서울산업대학교 기계공학과) ;
  • 용호택 (서울산업대학교 기계공학과) ;
  • 이승 (서울산업대학교 서울산업대학원 기계공학과)
  • Published : 2002.01.01

Abstract

The main objective of this study is to propose a practical two-microphone impedance tube method to measure the sound transmission loss for flexible sound isolation sheets without the use of the time-consuming and expensive reverberation room. This method was based on the sound decomposition theory developed by Seybert using the spectral density functions of the incident and reflected sound waves. In order to verify the validity of the experimental results, the measured sound transmission losses from the proposed method were compared with the measured data from the reverberation room method and the calculated data from the theory satisfying the mass law of sound isolation material. The resulted trends of the sound transmission losses versus frequencies for several different sound isolation sheets were almost same for each other and agreed quite well in both methods except at some low frequency region. From the experimental results, it was found that the accuracy of sound isolation capability obtained by two-microphone impedance tube method depends upon the microphone spacing, the distance from the first microphone to the test sample surface and the test sample location.

Keywords

References

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