Recent Advances on Active Noise Control

Abstract

This paper is a review of the history of active noise control (ANC), which uses sound to control and reduce unpleasant noise, and describes recent trends in the field. ANC is a technology for controling and reducing noise from noise sources (primary sources) by using controlled sounds from loudspeakers (secondary sources). This technology has become widely known to the public through noise-canceling headphones. However, three-dimentional (3D) noise control in public spaces such as offices and event halls, as well as in traffic and residential environments such as inside cars and houses, has not yet been widely implemented. In order to realize 3D noise control in such sound spaces, there are still many problems to overcome. In this paper, three representative virtual sensing methods for moving the zone of quiet (ZoQ) to an arbitrary location are first introduced, and their performance characteristics are compared. In addition, the causality constraint that is important in feed-forward ANC systems is explained, and an ANC system using oversampling is introduced as one solution to this problem. Furthermore, an application of machine learning, which has been used in various fields in recent years, to ANC systems is presented.