以前,大多数消声器都是被动式的。而最近对主动式消声器的研究日益多起来了。主动式消声法可分两种方式:一种是采用扬声器等做附加声源,产生与应消去噪声的声压波形反相位的声压波形,使两者相互抵消的方式。这种方式,从理论上说,在相当宽的低频带范围具有消声能力。但是,实际上存在着附加声源的耐久性及其所产生低频波等有关问题。另一种是根据声噪声的频率特性调整消声器的形状方式。本文就是研究这种方式加上控制技术的可变共振腔消声法。这是根据周期性噪声的周期变化,改变共振型消声器的共振腔容积,使共振频率跟踪噪声的主要频率,让共振型消声器的消声能力最大限度地发挥出来。这 In the past, most mufflers were passive. The recent research on active mufflers is growing. Active muffler can be divided into two ways: one is to use additional sound sources such as speakers to produce and should eliminate the noise of the sound pressure waveform anti-phase sound pressure waveform, so that the two offset each other. In this way, in theory, there is noise reduction over a fairly wide range of low frequencies. However, in fact, there are related issues such as the durability of the additional sound source and the low frequency waves it generates. The other is to adjust the shape of the muffler according to the frequency characteristics of acoustic noise. This article is a study of this approach coupled with variable cavity resonance control technology. This is based on periodic changes in the periodic noise, resonant muffler resonance cavity volume, so that the resonant frequency of the main frequency of noise tracking, so that the muffler resonance muffler to maximize the ability to play out. This