Abstract
The objective of this study is to develop an active noise controller based on optimal control approaches for enclosed Gaussian noise fields. By independent modal space control, the individual mode in the acoustic field is suppressed by the corresponding modal control exerted by loudspeakers. The formulation of the modal controller is considerably simplified because modal coupling is neglected. For the Gaussian noises considered in this study, the linear quadratic Gaussian algorithm in conjunction with the Kalman-Bucy filter is employed to perform state feedback and estimation. The developed controller is validated by simulations for a duct and a rectangular room. The results indicate that the technique will yield significant noise reduction if one uses the same number of controlled modes, microphones, and loudspeakers. Satisfactory performance is possible if one carefully avoids placing microphones and loudspeakers at the nodal points. © 1995, Acoustical Society of America. All rights reserved.