Noise Reduction in an Enclosed Sound Field Using Feedback Cluster Control (On the Suppression of Acoustical Energy Density)

Abstract

This paper presents global noise reduction in an enclosed sound field using feedback control based on the affinity between cluster control and suppression of acoustical energy density. First, an enclosed sound field is expressed in terms of a state space method. This is followed by the discussion on the validity of the acoustical energy density as a performance index of a control system. It is clarified here that the introduction of acoustical energy density results in the avoidance of uncontrollability. Next, the novel cluster control which is based on the suppression of acoustical energy density is proposed, its stability being analytically verified. Furthermore, from the viewpoint of numerical analyses, the validity of the proposed method is clarified. Finally, the relation between the proposed method and orthogonal contributors in an enclosed sound field is discussed, revealing that the conventional cluster control is the special case of the proposed method.