Active noise control at a moving virtual microphone using the SOTDF moving virtual sensing method

Abstract

Traditional local active noise control systems minimise the measured acoustic sound pressure to generate a zone of quiet at a physical error sensor. The resulting zone of quiet is generally limited in size and as such, placement of a physical error sensor at the location of desired attenuation is required, which is often inconvenient. Virtual acoustic sensors can be used to project the zone of quiet away from a physical error sensor to a remote location. A number of virtual sensing algorithms have been developed in the past and these have shown potential to improve the performance of local active noise control systems. However, it is likely that the desired location of maximum attenuation is not spatially fixed. In this paper, a stochastically optimal virtual microphone capable of tracking a desired virtual location in a modally dense three-dimensional sound field is developed using the Stochastically Optimal Tonal Diffuse Field (SOTDF) moving virtual sensing method. The performance of an active noise control system in generating a zone of quiet at the ear of a rotating artificial head with the SOTDF moving virtual sensing method has been experimentally investigated and experimental results are presented here.