Frequency domain adaptive algorithm for active noise control (2nd report, Investigation with an experimental duct model)

A new adaptive control algorithm in the frequency domain was propose. This frequency domain approach is an alternative to the ordinary filtered x least mean squares (LMS) algorithm in the time domain. A transfer characteristic of an acoustic path is identified adaptively in the frequency domain using the fast Fourier transform (FFT). The real time control of the noise reduction in an L formed duct model was carried out. A digital signal processor and a personal computer were used for the active noise control. The maximum noise reduction level of about 30 dB and the average reduction level of about 7 dB were obtained through the experiment. As a result, it was shown that this frequency domain adaptive algorithm has faster convergence compared to the ordinary filtered x LMS algorithm.