Global attenuation of broadband noise fields using energy density control

Abstract

The performance of the energy density control algorithm for controlling a broadband noise is evaluated in a one-dimensional enclosure. To avoid the noncausality problem of the control filter, which often happens 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 presented 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 squared pressure. It is shown that minimizing the energy density at a single location yields global attenuation results that are comparable to minimizing the potential energy. Furthermore, unlike controlling the squared pressure, the energy density control does not demonstrate any dependence on the error sensor location for this one-dimensional field. A practical implementation of the energy-based control algorithm is presented. Results show that the energy density control algorithm can be implemented using the two sensor technique with a tolerable margin of performance degradation.