ANC with multi-channel wave synthesis method (Phase 2: Experiments in real sound field)

摘要

It is strongly required to reduce noise at moving persons' ears in a noisy room by some active noise control (ANC) techniques. In the case of using fixed secondary sources, an ordinary feed forward ANC is difficult to apply for this purpose because it needs the online system identification of the error paths. On the other hand, Wave Synthesis (WS) method is useful because it doesn't need the above system identification, even though it is only applicable for periodic noise. In our previous paper, Multi-channel Wave Synthesis Method has been proposed and its usefulness has been proved by some simulations and simple experiments using electrical circuits. In this paper, a dual channel WS algorithm was installed to a DSP controller and its noise reducing performance was examined experimentally in a real sound field. The system could reduce periodic noise remarkably even if the error points were moving in certain conditions. However it became unstable in other conditions. The difference between these conditions is discussed in this paper.