Three-microphone two-cavity method for measuring sound transmission loss in a modified impedance tube

Authors

  • Yacoubou Salissou GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC J1K 2R1, Canada
  • Raymond Panneton GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC J1K 2R1, Canada
  • Olivier Doutres GAUS, Department of Mechanical Engineering, Université de Sherbrooke, QC J1K 2R1, Canada

Keywords:

Acoustic impedance, Loudspeakers, Microphones, A-plane, Acoustic materials, Finite length, Impedance tubes, Normal incidence, Sound insulation property, Sound transmission loss, Step discontinuity, Test samples, Two microphones, Two-cavity

Abstract

The normal incidence sound transmission loss (nSTL) is an important indicator to assess the sound insulation property of acoustic materials. The apparatus consists of a finite length rigid walled impedance tube with circularly shaped and uniform inner cross-section. The tube features a loudspeaker at one end and a movable piston at the other end. The loudspeaker is used to generate a plane wave field in the impedance tube. There are two microphones flush mounted upstream the test sample and one microphone flush mounted on the rigid end. Next, a 20-mm thick step discontinuity seeing as a non-symmetrical sample is tested and compared to the standard 4M2L method and 3M-TMTC method. One can note that similar results are obtained between the 3M2L and 4M2L methods, however 4M2L is noisier compared to 3M2L.

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Published

2011-09-01

How to Cite

1.
Salissou Y, Panneton R, Doutres O. Three-microphone two-cavity method for measuring sound transmission loss in a modified impedance tube. Canadian Acoustics [Internet]. 2011 Sep. 1 [cited 2021 Oct. 16];39(3):16-7. Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2388

Issue

Section

Proceedings of the Acoustics Week in Canada

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