Multichannel feedback control of interior road noise

Abstract

Active noise control systems offer a potential method of reducing the weight of passive acoustic treatments and, therefore, increasing a vehicles’ fuel efficiency. The active control of engine noise can be implemented cost-effectively by using the car audio loudspeakers as control sources and an array of low-cost microphones as error sensors. Such systems have been commercially implemented, but without also controlling road noise their subjective benefits may be limited. The active control of road noise using a feedforward control strategy has also been practically demonstrated, but these systems require a number of accelerometers to be mounted to the vehicle’s structure to obtain a coherent reference signal and, therefore, lead to a significant implementation cost. This paper proposes a multichannel feedback system for the active control of road noise, which uses an array of microphones and car audio loudspeakers, which is common to a feedforward engine noise control system. The design of the multichannel feedback controller is described and its performance is validated using offline simulations employing data measured in a small city car.