Adaptive active control of free space acoustic noise

This paper concerns adaptive active control of acoustic noise in free space. Conventional adaptive active noise control algorithms are efficient in acoustic ducts or headphones; however, they are very sensitive when being used in free space. An efficient adaptive active noise control algorithm for free space noise is developed based on analyzing noise field in a volumetric zone around the error microphone. The traditional algorithm and the proposed algorithm are fully implemented by using a high performance embedded controller. The implemented setup is then used for active control of acoustic noise in free space. Different experiments show that the traditional active noise control algorithm is not stable when being used for free space noise; however, the proposed algorithm is stable and attenuates noise in free space by about 15 dB.