Active noise control for closed space by concentrated mass model

Abstract

Adaptive feedforward control method is achieved by adding in a reverse-phase control sound of the same amplitude to noise near an error microphone. Because this method is aimed at controlling only noise near the error microphone, the control area is inherently narrow. Here, we propose an alternative method of noise control for an entire closed space. The proposed method is based on state feedback control and modeling of the acoustic space and loudspeaker by the concentrated-mass model. The coupled system is modeled as masses, connecting springs, connecting dampers, and base support dampers. We previously reported a method for simple one-dimensional acoustic space control. In this paper, we show the design of a control system for twodimensional acoustic spaces. By the proposed method, noise in the acoustic space was experimentally controlled, with the finding that noise in the entire acoustic space was reduced around the resonance frequencies. Furthermore, the limit of the control effect are considered within the proposed system.