Author: Prezelj Jurij Čudina Mirko
Publisher: S. Hirzel Verlag
ISSN: 1610-1928
Source: Acta Acustica united with Acustica, Vol.93, Iss.1, 2007-01, pp. : 63-72
Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.
Abstract
An active noise control (ANC) method is particularly suitable for noise control in ventilation ducts. Usually a feed-forward configuration is used. Performance of a feed-forward ANC system in an air conditioning duct depends on the quality of the reference signal, which should be perfectly correlated with the primary noise. Acoustic feedback corrupts the reference signal and is one of the main problems of broadband feed-forward ANC systems in ducts. Directivity of the secondary source reduces the acoustic feedback effect. Two highly directional designs of the secondary source were developed: the Transmission Line (TL) secondary source and the Quarter Wavelength (QW) secondary source. It has been shown that this kind of acoustic feedback reduction unburdens the adaptive FX-LMS algorithm and speeds up its convergence. An additional advantage of both proposed secondary sources is that a significant transmission loss is achieved, even when the loudspeaker is turned off.
Related content
A Travelling Wave Approach to Active Noise Control in Ducts
Journal of Sound and Vibration, Vol. 219, Iss. 2, 1999-01 ,pp. :
Active Control of Multi-Modal Propagation of Tonal Noise in Ducts
By Laugesen S.
Journal of Sound and Vibration, Vol. 195, Iss. 1, 1996-08 ,pp. :