Application of wave field synthesis to active control of highly non-stationary noise

Active Noise Control (ANC) methods have been successfully applied to the cancellation of stationary noise. Classical ANC systems use adaptive filtering techniques to produce a waveform that is opposite, or counter-phase, to the signal noise we would like to cancel. However, when the noise is of short duration, adaptive filtering cannot be used since convergence is not achieved. In this paper, a novel active control technique for non-stationary noise is presented. The method uses wave field synthesis (WFS) for the construction of the canceling waveform. The system is tailored for an outdoor environment. The noise acoustic field is acquired by microphones and processed by a WFS engine to pilot a linear array of secondary sources. Experimental results, obtained from both simulations and true tests, demonstrate that the proposed method is able to diminish the overall noise perceived in the area covered by the system.