Head tracking for local active noise control
Stephen J. Elliott, Marcos Simón, Jordan Cheer, Woomin Jung · ePrints Soton (University of Southampton) · 2015
The spatial extent of the cancellation that can be achieved with a local active sound control system is limited, particularly at frequencies above about 300 Hz, so that control of the pressure at fixed points in space does not give satisfactory performance as the listener’s head moves about, unless the position of the head can be tracked. The availability of low-cost head tracking systems for gaming applications opens up the possibility of such a head tracking active control system at a modest cost. In the experiments reported here, such a system was used to track the head position in a local active sound controller, implemented in a headrest. The positions of the listener’s ears were calculated from the head position. This was used in lookup tables to estimate both the responses from the secondary sources to the remote microphone positions at the ear, and also the weightings on an array of monitoring microphones mounted on the headrest, used to estimate the pressures at these remote microphone positions, using an observer. These estimates were then used to adapt the two control filters driving the secondary sources.