In-situ acoustic impedance estimation based on sparse array processing

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Measurement of the acoustic properties of materials typically relies upon idealized sound fields, e.g., anechoic, normal incidence or diffuse fields. Although approximations to these idealized sound fields can be recreated under laboratory conditions, there is no reliable way of characterizing acoustic properties of materials in-situ.

Recent findings by the applicants show remarkable potential in impedance estimation using microphone arrays, via reconstructing the sound pressure and particle velocity on the surface of the material. Additionally, recent results indicate that compressive sensing (based on sparsity constrains via l-1 minimization), is a powerful approach for determining the amplitudes and directions of the incident and reflected waves, providing accurate reconstruction. The method is also successful in estimating the angle dependent absorption coefficient, which is of significance for the numerical modeling of rooms.

This innovation project will apply the proposed microphone array techniques to real applications in enclosures: An initial validation under laboratory conditions, followed by measurements in a medium-sized room, emulating realistic in-situ conditions. The combination of expertise from the partners of the project is a strong asset; it counts with leading expertise in microphone array measurements, room acoustics, and spatial processing of sound fields.

Project participants:
DTU Electrical Engineering
Brüel & Kjlær
Bang & Olufsen

For more information contact Project Manager
Efren Fernandez Grande, DTU Electrical Engineering,