Free-field calibration of measurement microphones at high frequencies

Salvador Barrera Figueroa, Knud Rasmussen, Antoni Torras Rosell, Finn Jacobsen

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

    Abstract

    Measurement microphones are typically calibrated in a free field at frequencies up to 50 kHz. This is a sufficiently high frequency for the most of sound measurement applications related with noise assessment. However, other applications such as assessment of the noise emitted by ultrasound cleaning machines, and fail detection in aeronautic structures require that the sensitivity of the microphone is known at frequencies up to 150 kHz. Such a high frequency can only be reached using small measurement microphones with very low sensitivity. Thus, in order to extend the frequency range of free-field calibration the measurement system, and measurement methods must undergo a series of changes and adaptations including the type of measurement signal, methods for eliminating unwanted reflections from walls, cross-talk, etc. Furthermore, the properties of the measurement microphones used in high frequency calibration are relatively less known, and must be determined either from experimental methods or numerically. This paper presents the results of an initial investigation of the calibration of measurement microphones at high frequencies. A strategy for the changes and adaptations to the existing measurement methodologies, and the determination of the microphone parameters is outlined.
    Original languageEnglish
    Title of host publicationINTER- NOISE 2011 Proceedings
    Publication date2011
    Publication statusPublished - 2011
    EventINTER-NOISE 2011 : 40th International Congress and Exposition on Noise Control Engineering - Osaka, Japan
    Duration: 4 Sept 20117 Sept 2011
    Conference number: 40

    Conference

    ConferenceINTER-NOISE 2011 : 40th International Congress and Exposition on Noise Control Engineering
    Number40
    Country/TerritoryJapan
    CityOsaka
    Period04/09/201107/09/2011

    Keywords

    • Free-field reciprocity
    • Microphone calibration

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