GLOBAL ATTENUATION OF BROAD-BAND NOISE FIELDS USING ENERGY DENSITY CONTROL

The performance of the energy density control algorithm for controllin g a broadband noise is evaluated in a one-dimensional enclosure. To av oid the noncausality problem of the control filter, which often happen s in a frequency domain optimization, analyses presented in this paper are undertaken in the time domain. This approach provides the form of the causally constrained optimal controller. Numerical results are pr esented to predict the performance of the active noise control system, and indicate that improved global attenuation of the broadband noise can be achieved by minimizing the energy density, rather than the squa red pressure. It is shown that minimizing the energy density at a sing le location yields global attenuation results that are comparable to m inimizing the potential energy. Furthermore, unlike controlling the sq uared pressure, the energy density control does not demonstrate any de pendence on the error sensor location for this one-dimensional field. A practical implementation of the energy-based control algorithm is pr esented. Results show that the energy density control algorithm can be implemented using the two sensor technique with a tolerable margin of performance degradation. (C) 1997 Acoustical Society of America.