Document Type

Thesis

Date of Award

2011

Keywords

Differential microphones, Mems microphones, Ormia ochracea, Plane wave prediction, Second-order gradient, Sound field

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Ronald N. Miles

Second Advisor

Mark L. Fowler

Third Advisor

Bruce T. Murray

Subject Heading(s)

Microphone -- Testing; Directional hearing -- Testing; Acoustical engineering

Abstract

The focus of this thesis is the testing and characterizing of directional microphones, designed based on the ear of the fly Ormia ochracea. The response of these microphones is modeled as a linear combination of the gradients of the sound field. A least squares approach is employed in order to determine the transfer functions between the response and these gradients. Knowledge of these complex transfer functions is crucial in understanding the nature and quality of the response of these microphones.

Once determined, these transfer functions are used to simulate the plane wave response of differential microphones. This process is invaluable to acoustic research groups that do not have access to an anechoic chamber because the plane wave response is a standard by which acoustic devices are measured. This process was validated by comparing the true plane wave response of an industry standard differential microphone with its simulated plane wave response.

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