Isotropy in decaying reverberant sound fields

The Journal of the Acoustical Society of America, vol. 148, pp. 1077–1088

Abstract

A method of evaluating sound field isotropy in decaying reverberant sound fields is presented. The proposed method extends the experimental framework outlined in [J. Acoust. Soc. Am. 143(4), 2514-2526 (2018)] and analyzes the decaying sound field in a reverberation room. Spatio-temporal measurements of the sound field are obtained, and a wavenumber decomposition is performed as a function of time, which serves to examine the directional properties of the sound field and its angular symmetry. Experimental results are obtained in a reverberation room in four different configurations (the empty room, with an absorber on the floor, with panel diffusers, and without them). The results demonstrate how isotropy tends to increase or decrease as a function of time, depending on the disposition of the diffusing and absorbing elements. Diffusers are found to effectively redirect the energy in the room, although they do not succeed in generating a uniform incidence on the sample. The proposed approach makes it possible to analyze the specific processes occurring in a reverberation chamber and can provide valuable insights in the process of standardization to verify the directional properties found in each reverberation room.

Authors 3

1. Mélanie Nolan Aachen Institute of Technical Acoustics

   RWTH Aachen University · Technical University of Denmark

   Affiliation as printed

   Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark 1 , DK-2800 Kongens Lyngby, Denmark

   Institute of Technical Acoustics, RWTH Aachen University, 52074 Aachen, Germany

2. Marco Berzborn Aachen Institute of Technical Acoustics

   RWTH Aachen University · Technical University of Denmark

   Affiliation as printed

   Institute of Technical Acoustics, RWTH Aachen University 2 , 52074 Aachen, Germany

   Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark

3. Efrén Fernández-Grande Aachen Institute of Technical Acoustics

   RWTH Aachen University · Technical University of Denmark

   Affiliation as printed

   Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark 1 , DK-2800 Kongens Lyngby, Denmark

   Institute of Technical Acoustics, RWTH Aachen University, 52074 Aachen, Germany