Impedance estimation of a finite absorber based on spherical array measurements

Antoine Philippe André Richard, Efren Fernandez Grande, Jonas Brunskog, Cheol-Ho Jeong

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


A method to characterize the surface impedance of materials is presented. The estimation is based on pressure measurements with a spherical microphone array. These measurements are used to reconstruct the sound pressure and particle velocity on the sample’s surface, from which the material’s impedance is inferred. The accuracy of the reconstruction is improved by using compressive sensing, where the wave field is represented with only a few components, ideally an
incident and a reflected wave. However, at low frequencies, diffraction from the edges contributes considerably to the sound field. This leads to a deterioration of the impedance estimation, which is clearly visible in initial experimental results. The proposed methodology makes it possible to characterize the edge effect, and subsequently compensate for it in the processing, emulating measurements on an infinite sample.
Original languageEnglish
Title of host publicationProceedings of the 22nd International Congress on Acoustics
Number of pages10
Publication date2016
Article numberPaper ICA2016-506
Publication statusPublished - 2016
Event22nd International Congress on Acoustics : Acoustics for the 21st century - Catholic University of Argentina, Buenos Aires, Argentina
Duration: 5 Sep 20169 Sep 2016


Conference22nd International Congress on Acoustics
LocationCatholic University of Argentina
CityBuenos Aires
Internet address


  • Impedance measurement
  • Spherical array

Cite this

Richard, A. P. A., Fernandez Grande, E., Brunskog, J., & Jeong, C-H. (2016). Impedance estimation of a finite absorber based on spherical array measurements. In Proceedings of the 22nd International Congress on Acoustics [Paper ICA2016-506]