Active Noise Control with a Moving Evaluation Point

Abstract

Active noise control (ANC) in 3-dimensional sound field, e.g. an office room, is investigated in this paper. Since the size of the controlled area normally depends on the wave length of the target noise, it is difficult to control in the whole room using ANC technique. Instead, around-head-control is investigated in this paper. To realize the around-head-control, an evaluation point is required to correspond with the head movement while controlling. However, the evaluation point movement while controlling has not been considered in a conventional ANC. Against this problem, a new algorithm is proposed in this paper. The algorithm updates filters by using Time-Delay filter and Distance-Attenuation coefficient. Time-Delay filter and Distance-Attenuation coefficient are calculated from the position of the evaluation point. The computer simulations are carried out, and the validity of the new algorithm is shown.