Technology Development for Directional Acoustic Arrays – Journal of the Acoustical Society of America Dec 2001

The need for noise source localization and characterization has driven the development of advanced sound field measurement techniques using microphone arrays; however, the cost and complexity of these systems limit their widespread use. One common application is the study of aircraft noise in wind tunnels. The arrays typically consist of moderate numbers (<40) of conventional condenser microphones and range in size from several inches to several feet. Arrays consisting of more microphones and/or the use of multiple arrays may be needed to analyze complex multipole noise sources. However, the feasibility of scaling the current technology to multiple arrays with large numbers of microphones is limited by the cost per channel, array mobility, and data handling efficiency. A reduced cost, mobile, high speed 16‐channel array has been constructed to demonstrate key technologies to address these scaling issues. The system is based on a hybrid package that combines a silicon piezoresistive microphone and amplification circuitry. Each package is socketed into a printed circuit board, providing electrical connections and structural support. High speed data acquisition and signal processing hardware is used to generate the array response in near real time. The results of the initial array calibrations are presented.

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