Active noise control at a moving virtual sensor in three-dimensions

Abstract

A common problem in local active noise control is that the zone of quiet generated at the physical error sensor is limited in size. This requires that the physical error sensor (the microphone) is placed at the desired location of attenuation (the ear), which is often inconvenient. Virtual acoustic sensors overcome this by estimating the pressure at a location that is remote from the physical sensor and therefore, when combined with an active noise control system, generate a zone of quiet at the desired location of attenuation. While virtual acoustic sensors have shown potential to improve the performance of local active noise control systems, it is, however, likely that the desired location of attenuation is not spatially fixed. A method for generating a virtual sensor that tracks a three-dimensional trajectory in a three-dimensional sound field is summarised in this paper. The performance of an active noise control system in generating a zone of quiet at the ear of a rotating head in a three-dimensional cavity has been experimentally investigated and the results included here demonstrate that moving virtual sensors provide improved attenuation compared to fixed virtual sensors or fixed physical sensors.