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Modal Analysis of Rigid Microphone Arrays using Boundary Elements

Authors Kaiser, F.
Year 2012
Thesis Type Master's thesis
Topic Audio Signal Processing
Keywords boundary element method, microphone arrays, acoustic scattering, singular value decomposition, modal array processing
Abstract This thesis deals with compact rigid microphone arrays and their acoustic modal representation for sound field reconstruction and beamforming. A method for obtaining surface modes of arbitrarily shaped rigid microphone arrays based on the boundary element method (BEM) and the singular value decomposition (SVD) is introduced and an analysis of spherical and cylindrical arrays is presented. The modal functions are found to be frequency dependent except for frequencies below kr ≈ 1. This indicates that a simplification of the array signal processing can be applied for low frequencies. Further, the spatial resolution properties of different rigid spherical and cylindrical array shapes were analyzed. The different configurations simulated using the BEM were found to have similar vertical and horizontal resolution.
Supervisors Zotter, F., Fazi, F.