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A single microphone capillary-based system for measuring the complex input impedance of musical wind instruments

Sharp, David; Mamou-Mani, Adrien and van Walstijn, Maarten (2011). A single microphone capillary-based system for measuring the complex input impedance of musical wind instruments. Acta Acustica united with Acustica, 97(5) pp. 819–829.

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Capillary-based systems for measuring the input impedance of musical wind instruments were first developed in the mid-20th century and remain in widespread use today. In this paper, the basic principles and assumptions underpinning the design of such systems are examined. Inexpensive modifications to a capillary-based impedance measurement set-up made possible due to advances in computing and data acquisition technology are discussed. The modified set-up is able to measure both impedance magnitude and impedance phase even though it only contains one microphone. In addition, a method of calibration is described that results in a significant improvement in accuracy when measuring high impedance objects on the modified capillary-based system. The method involves carrying out calibration measurements on two different objects whose impedances are well-known theoretically. The benefits of performing two calibration measurements (as opposed to the one calibration measurement that has been traditionally used) are demonstrated experimentally through input impedance measurements on two test objects and a Boosey and Hawkes oboe.

Item Type: Journal Article
Copyright Holders: 2011 S. Hirzel Verlag/EAA
ISSN: 1861-9959
Extra Information: PACS no. 4358.Bh, 43.75.Ef, 43.75.Fg, 43.75.Yy
Keywords: musical acoustics; input impedance; capillary technique; musical wind instruments
Academic Unit/Department: Mathematics, Computing and Technology > Engineering & Innovation
Mathematics, Computing and Technology
Item ID: 29459
Depositing User: David Sharp
Date Deposited: 14 Sep 2011 12:27
Last Modified: 24 Feb 2016 06:28
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