UBC Undergraduate Research

Acoustic measurements using a microphone array Smit-Anseeuw, Nils; Zimmer, Aaron

Abstract

A microphone array is designed, built and used for analyzing the radiation of a single test instrument, an oud. Two analysis algorithms are implemented for this purpose, radiation mapping and delay and sum beamforming. Radiation mapping is used to determine the spatial radiation intensity of the instrument, while beamforming is used to map the source locations on the instrument’s soundboard. In this report, the mechanical design history of the microphone array is presented, as well as a detailed overview of the finalized design. The development and testing of the beamforming algorithm is then summarized, followed by a detailed description and analysis of the final algorithm. Radiation maps for the 5 largest vibration modes of the oud are produced and presented, as well as beamforming results for various frequencies. Some investigations are subsequently made into the validity of the results, and recommendations are given for their further verification and improvement. It is concluded that beamforming can consistently and successfully locate single monopole sound sources. While the results of beamforming for the more complicated sources found in the oud soundboard remain far from conclusive, their consistency and intuitive placement suggest that they hold some valid results. In order to fully support this hypothesis, it is concluded that modal analysis should be performed on the oud, comparing the results with those produced by beamforming.

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Attribution-NonCommercial-NoDerivatives 4.0 International

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