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 Sep 20117 Sep 2011
Conference number: 40

Conference

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

Keywords

  • Free-field reciprocity
  • Microphone calibration

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