Resistive mufflers mainly use porous sound-absorbing materials to reduce noise. The sound-absorbing material is fixed on the inner wall of the airflow channel or arranged in the pipeline in a certain way to form a resistive muffler. When the sound wave enters the resistive muffler, a part of the sound energy is rubbed in the pores of the porous material and converted into heat energy and dissipated, so that the sound wave passing through the muffler is weakened. A resistive muffler is like a purely resistive electrical circuit, and the sound-absorbing material is similar to a resistor. Therefore, people call this muffler a resistive muffler. The resistive muffler has good muffling effect on medium and high frequency, but poor effect on low frequency.