A method of configuring fixed coefficient active noise controllers for traffic noise reduction

© 2017 Institute of Noise Control Engineering. All Rights Reserved. In practical applications of Active Noise Control (ANC) systems on traffic noise reduction, the noise sources to be controlled are usually far away from the system and are continuously moving, hence there are no fixed noise sources for configuring the controller. This paper proposes a method to configure fixed coefficient ANC systems for the scenario of traffic noise reduction. In the tuning process, a pseudo noise source is proposed to be placed near a single channel ANC system to adjust the controller. After the optimal coefficients of the controller are obtained for this situation, the coefficients are fixed and the ANC system is utilized to cancel the actual noise source in the far-field. Simulation results showed that when the noise source is a point source located very far away from the ANC system, moving the pseudo noise source farther away from the single-channel ANC system can effectively increase the noise reduction. However, if the noise source is closer to the single-channel ANC system than the pseudo noise source, the performance deteriorates quickly. When the primary noise originates from a line array of incoherent point sources far from the ANC system, moving the pseudo noise source farther away from the system can effectively increase the noise reduction; however, the performance of the single channel ANC system decreases with frequency and deteriorates when there are many noise sources present simultaneously as in the traffic noise scenario. Experiments were conducted in a laboratory environment for one noise source and three noise sources, and the results are consistent with the simulations