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Advances in Acoustics and Vibration
Volume 2011 (2011), Article ID 697108, 9 pages
http://dx.doi.org/10.1155/2011/697108
Research Article

Analysis and Optimal Condition of the Rear-Sound-Aided Control Source in Active Noise Control

1Department of Electrical Engineering, Technical University of Darmstadt, 64283 Darmstadt, Germany
2Department of Mechanical Engineering, Faculty of Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan

Received 14 March 2011; Revised 3 May 2011; Accepted 18 May 2011

Academic Editor: Arnaud Deraemaeker

Copyright © 2011 Karel Kreuter and Yasuhide Kobayashi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An active noise control scenario of simple ducts is considered. The previously suggested technique of using an single loudspeaker and its rear sound to cancel the upstream sound is further examined and compared to the bidirectional solution in order to give theoretical proof of its advantage. Firstly, a model with a new approach for taking damping effects into account is derived based on the electrical transmission line theory. By comparison with the old model, the new approach is validated, and occurring differences are discussed. Moreover, a numerical application with the consideration of damping is implemented for confirmation. The influence of the rear sound strength on the feedback-path system is investigated, and the optimal condition is determined. Finally, it is proven that the proposed source has an advantage of an extended phase lag and a time delay in the feedback-path system by both frequency-response analysis and numerical calculation of the time response.