防止空调管道的噪声,以前大多采用图1所示的被动型消声器。由于被动型消声器在低频域的消声量、压力损失及气流所致的二次噪声等方面存在很多问题,因此出现了对管道内传播的噪声利用干涉效应辐射反相位的附加声进行消声的主动型消声器的方案,但其实用化技术却成为多年来的研究课题。近年来,由于电子技术的飞速发展,许多国家在主动型消声器的实用化研究方面取 To prevent noise in air-conditioning ducts, passive silencers as shown in Fig. 1 were used in most cases. Because there are many problems in the passive muffler in the low-frequency area such as noise reduction, pressure loss, and secondary noise caused by the air flow, there is an additional sound for noise propagation in the pipeline that uses the anti-phase effect of the interference effect to cancel noise. Active muffler solutions, but its practical technology has become a research topic for many years. In recent years, due to the rapid development of electronic technology, many countries have taken practical measures for active mufflers.