Static pressure and temperature coefficients of laboratory standard microphones

Knud Rasmussen

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    Abstract

    The sensitivity of condenser measurement microphones depends on the environmental conditions due to the changes in the acoustic properties of the enclosed air between diaphragm and back-electrode and in the cavity behind the backelectrode. A theoretical investigation has been performed based on an extended lumped parameter representation of the mechanical and acoustical elements of the microphone, assuming the velocity distribution of the diaphragm to follow the zero-order Bessel function. The extension involves the frequency dependency of the dynamic diaphragm mass and stiffness as well as a first-order approximation of resonances in the back cavity. It was found that each of the coefficients, for a given type of microphone, can be expressed by a single function when the coefficients are normalized by their low-frequency value and the frequency axis normalized by the individual resonance frequency of the microphone. The static pressure and temperature coefficients were determined experimentally for about twenty samples of type BK 4160 and BK 4180 microphones. The results agree almost perfectly with the predictions for BK 4160, while some modifications of the lumped parameter values are called for to make the results for BK 4180 fit the predicted values.
    Original languageEnglish
    JournalAcoustical Society of America. Journal
    Volume100
    Issue number4
    Pages (from-to)2671-2671
    ISSN0001-4966
    DOIs
    Publication statusPublished - 1996
    Event3rd Joint Meeting of ASA and ASJ - Honolulu
    Duration: 1 Jan 1996 → …

    Conference

    Conference3rd Joint Meeting of ASA and ASJ
    CityHonolulu
    Period01/01/1996 → …

    Bibliographical note

    Copyright (1996) 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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