Multi-channel active noise control using parametric array loudspeakers

In this paper, a multi-channel active noise control (ANC) using parametric array loudspeakers (PALs) is proposed to solve the noise problem in a factory. The PAL is a type of directional loudspeaker making use of the nonlinear acoustic effects. There are two advantages when PALs are used as the secondary sources in a multi-channel ANC system. First, noise levels can be reduced at the targeted locations, while the sound pressure levels at the other locations are not affected. Second, the cross-talk secondary path models can be removed, because the sound field reproduced by one PAL has negligible interference with the other PALs. When the proposed ANC system is implemented with fixed coefficient noise control filters, the computational complexity is further reduced. Based on a real-time implementation in a digital signal processor (DSP), experiment results are obtained to demonstrate the performance of the proposed ANC system.