Research On Active Noise Control Algorithm Based On Masking Effect

The traditional passive noise canceling method is only effective for reducing mid-high frequency noise,and the effect of low-frequency noise is low.The emergence of active noise control technology solves this problem.The Filtered-X Least Mean Square(FXLMS)algorithm and the Filtered-Error Least Mean Square(FELMS)algorithm are two widely used algorithms in active noise control algorithms.It has the advantages of good control effect,low cost and small amount of calculation.But they do not fully considered the subjective response of the human ear in the process of noise reduction.The masking effect is an important subjective response of the human ear.The FXLMS algorithm can be combined with the masking effect to improve the noise reduction effect while focusing on the subjective response of the human ear.In this paper,based on the active noise control technology and the masking effect,the time-domain post-masking principle of the Zwicker's four-level sub-model is analyzed,the coordinates of the starting point of masking are founded,and the post-sound masking model is designed.The simulation verifies the feasibility of this masking model in processing sound pressure signals.During the noise reduction process of the FXLMS algorithm,the postmasking sound pressure model is called,and the post-masking residual signal is sent to the controller for noise reduction,and the FXLMS(Backward-Masking FXLMS Algorithm,BM-FXLMS)algorithm based on the post-masking effect is obtained to achieve the purpose of adding the subjective response of the human ear to the FXLMS algorithm for noise reduction.Taking different automobile engine noises as examples to verify the noise reduction performance of BM-FXLMS algorithm,FXLMS algorithm and FELMS algorithm,the noise reduction performance is evaluated by MSE curve and loudness and sound pressure level after noise reduction,and the noise reduction effect of BM-FXLMS algorithm is obtained Better than FXLMS and FELMS algorithms.On this basis,the influence of the step size and order within a certain range on the noise reduction performance of the BM-FXLMS algorithm is discussed,and the corresponding suitable step size and suitable order range are obtained.Under the same step size and order,comparing the noise reduction effects of three noises in different environment under the BM-FXLMS algorithm,FXLMS algorithm and FELMS algorithm,it is concluded that the BM-FXLMS algorithm's ability to handle noise is not only superior to the FXLMS algorithm And FELMS algorithm,the improvement effect of some sound quality parameters is also above the two.In this paper,a post-sound pressure masking model is designed,which implements the post-masking process of the sound pressure signal and applies it to the FXLMS algorithm.The BM-FXLMS algorithm is obtained,and the noise reduction effect of the BM-FXLMS algorithm is verified by experiments.The FXLMS algorithm and FELMS algorithm achieve the purpose of fully considering the subjectivity of the human ear while improving the noise reduction effect.