Muffler

Concerning its uses, there are mainly three kinds of dissipative muffler, resistance and composite impedance muffler. Dissipative muffler mainly uses porous absorption material that is fixed on the inner wall of the air flow channel, or arranged in the pipe according to certain way to reduce noise. Resistance muffler is made up by the pipe and room of mutations in the interface ,which seems like a  acoustic filter, and have attenuation using when the sound go through the pipe of mutation. And the composite impedance muffler has gathered the structures of the former two kinds with better ideal sound-absorbing effect, but the bigger size.