Comparison of feedforward, feedback and hybrid structures on an ANC headphone

Feedforward, feedback and hybrid structures are three main structures used in active noise control (ANC) systems. This paper aims to compare their effectiveness on an ANC headphone implemented on a floating point digital signal processing platform. Detailed performance of the ANC headphone with three structures is tested respectively in an anechoic chamber. Experiment results show that the feedforward structure is more sensitive to the primary noise coming directions, but provides better performance than the feedback structure. The hybrid structure can remedy partly the sensitivity of the primary noise coming directions of the feedforward structure and achieves the best performance. With the optimized parameters, the hybrid structure can have more than 20 dB noise reduction in the frequency range from 100 Hz to 400 Hz band and 5∼15 dB noise reduction from 500 to 800 Hz band