Main categories of Silencer

The muffler principle of silencer is to use the appropriate combination of cavity and tube to achieve two kinds of effects of silencing:

First, the use of pipe cross-section mutation (i. e., the change of sound resistance) to transmit the acoustic waves along the pipeline to the source direction, so that the sound can reflect back to the same place;

The second is to use several interfaces of reflection, to make the original first forward wave of acoustic waves back to the original point, and again to retrace forward spreading, the point and not yet reflected the second forward wave of the waves convergence, and the two in the amplitude of equal, in phase difference 180 degrees of odd number of times, thus interference with each other offset.