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Application of the Local Plane Wave Method for In-Situ Absorption Measurements Using a Spherical Microphone Array

Conventional absorption measurements require an impedance tube or reverberation chamber. The Local Plane Wave (LPW) method enables in-situ measurements in arbitrary fields. In this ICSV publication, the authors apply this method to a spherical microphone array (SonoCat).

In-situ absorption measurements using a spherical array

The Local Plane Wave (LPW) method models the sound field locally as an incident and reflected plane wave to determine in-situ sound absorption, independent of the global field. The authors apply this to a rigid spherical array consisting of eight digital MEMS microphones (the SonoCat). By analytically modeling the scattering from the sphere using spherical harmonics, the undisturbed field is reconstructed using the least-squares method. Validation using FEM and laboratory measurements on melamine foam shows strong agreement with ISO 10534-2 impedance tube measurements from the University of Twente.

Citation for the publication

  • Authors: Niels Consten (SoundInsight BV), Anne de Jong (SoundInsight BV / ASCEE), and Ysbrand Wijnant (SoundInsight BV / University of Twente)

  • Publication: Proceedings of the 24th International Congress on Sound and Vibration (ICSV24)

  • Location & Date: London, United Kingdom (July 23–27, 2017)

  • Keywords: In-situ absorption, Local Plane Wave (LPW) method, spherical microphone array, SonoCat, MEMS microphones

  • Download the conference paper (PDF)

  • View the publication on the University of Twente Research Portal

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