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Acoustic Impedance Tube With Exponential Flare for Testing Large Diameter Samples Over a Wide Range of Frequencies

IP.com Disclosure Number: IPCOM000059836D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Nobile, MA: AUTHOR

Abstract

An impedance tube has a relatively narrow diameter at the end where a sound source is located, and it is flared exponentially to a large diameter at the end where a sample is located for a test of absorption coefficient and acoustic impedance. The flared impedance tube supports plane waves over a wide frequency range. It avoids the usual procedure of testing at high frequencies with a narrow fixed diameter tube and testing at l frequencies with a larger fixed diameter tube.

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Acoustic Impedance Tube With Exponential Flare for Testing Large Diameter Samples Over a Wide Range of Frequencies

An impedance tube has a relatively narrow diameter at the end where a sound source is located, and it is flared exponentially to a large diameter at the end where a sample is located for a test of absorption coefficient and acoustic impedance. The flared impedance tube supports plane waves over a wide frequency range. It avoids the usual procedure of testing at high frequencies with a narrow fixed diameter tube and testing at l frequencies with a larger fixed diameter tube.

A mathematical analysis has been made to show that the absorption coefficient and acoustic impedance can be obtained from the test results and that either the one-microphone standing wave ratio technique or the two-microphone transfer function technique may be employed.

Disclosed anonymously.

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