Design of feedforward active noise canceling earphones with acoustic feedback
Almost all the existing feedforward active noise-canceling earphones use a structure in which the rear chamber of the loudspeaker is sealed and isolated from the reference microphone.This design avoids secondary acoustic feedback,but it is difficult to design the optimal controller.This paper proposes a new feedforward structure with acoustic feedback,in which the sound inlet of the reference microphone faces the ear and is located in the rear cavity of the speaker.With this new structure,we derive the expression of the optimal controller,and propose to adopt cascade Biquad filters to approximate the optimal controller.The optimal controller design is modeled as a multi-constraint multi-parameter optimization problem,and the differential evolution algorithm is used to find the global optimal solution of the parameter vector.Experiments have found that the designed earphone has a smoother optimal controller frequency response curve than traditional one,so the former requires less filter resources.The test results show that the proposed earphone achieves larger bandwidth and higher noise reduction and without any stability problems such as howling.
Active noise controlAcoustic feedbackFeedforward control
万方数据
维普
