Performance improvements on MEFX-LMS based noise cancellation system in vehicle cabin

Multiple Error Filtered X (MEFX) LMS (Least Mean Squares) based booming noise or engine noise cancellation system has been implemented in the automobile and the reciprocate engine airplane cabin to provide practical solutions to improve the annoying noisy environment. The noises are well known in that they behave as resonance noise of the fuselage. A significant difference in noise level or power spectrum between control points is often observed. For the cabin noise cancellation system, all passenger areas are expected to be quiet. Because the MEFX LMS algorithm minimizes the total squared power of the error signals, degradation of increase in the noise level is observed in certain situations. In this paper, we demonstrate such behavior of the algorithm and propose a method to improve the practical performance of the system