On determination of microphone response and other parameters by a hybrid experimental and numerical method

Salvador Barrera Figueroa (Invited author), Finn Jacobsen (Invited author), Knud Rasmussen (Invited author)

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Abstract

Typically, numerical calculations of the pressure, free-field and random-incidence response of a condenser microphone are carried out on the basis of an assumed displacement distribution of the diaphragm of the microphone; the conventional assumption is that the displacement follows a Bessel function. This assumption is probably valid at frequencies below the resonance frequency. However, at higher frequencies the movement of the membrane is heavily coupled with the damping of the air film between membrane and back plate, and with resonances in the back chamber of the microphone. A solution to this problem is to measure the velocity distribution of the membrane by means of a non-contact method, such as laser vibrometry. The measured velocity distributions can be used together with a numerical formulation such as the Boundary Element Method for estimating the microphone response and other parameters such as the acoustic centres. In this work, a hybrid method is presented. The velocity distributions of condenser Laboratory Standard microphones were measured using a laser vibrometer. This measured velocity distribution was used for estimating the microphone responses and parameters. The agreement with experimental data is good. This method can be used as an alternative for validating the parameters of the microphones determined by classical calibration techniques.
Original languageEnglish
JournalAcoustical Society of America. Journal
Volume123
Issue number5
Pages (from-to)3229-3229
ISSN0001-4966
DOIs
Publication statusPublished - 2008
EventAcoustics'08 - Paris, France
Duration: 29 Jun 20084 Jul 2008
http://webistem.com/acoustics2008/acoustics2008/cd1/data/index.html

Conference

ConferenceAcoustics'08
CountryFrance
CityParis
Period29/06/200804/07/2008
Internet address

Bibliographical note

Copyright (2008) Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.

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