Measurement of in-duct acoustic properties by using a single microphone with fixed position

Yat Sze Choy, Lixi Huang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)


Acoustic properties of sound absorption materials and other acoustic structures can be measured in an impedance tube using the well-established two-microphone method to resolve the two traveling wave components of a standing wave pattern. The accuracy of such measurements depends crucially on the calibration of the two microphones placed in close proximity. To eliminate such calibration, the one-microphone method [Chu, J. Acoust. Soc. Am. 80, 555-560 (1986)] uses the same microphone to probe at two positions sequentially using the voltage driving the loudspeaker as a reference signal. A variant of this method is introduced in this study in which the microphone is fixed at one position while a rigid end plate moves between two positions to resolve the standing wave. The sound source is installed as a side branch, and its driving signal is also used as a reference in the two-step measurement. Close agreement is found with the established two-microphone method, and factors which might affect the accuracy of the new technique are discussed. As a demonstration of the robustness of the method, a low-budget electret microphone is used and the result also matches well with those obtained by the two-microphone method with high-quality condenser type microphones.
Original languageEnglish
Pages (from-to)3498-3504
Number of pages7
JournalJournal of the Acoustical Society of America
Issue number6
Publication statusPublished - 1 Dec 2004

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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