Abstract: Shunt loudspeaker is a new resonant sound-absorbing structure which converts sound energy into mechanical energy and then into electrical energy to dissipate finally in the form of heat energy. Reasonable design of shunt circuit parameters can obtain the desired sound absorption frequency. In order to realize the adjustable natural frequency of loudspeaker, a shunt circuit with negative resistance circuit and inductance circuit in series is proposed in this paper. The experimental results show that the natural frequency of shunt loudspeaker decreases with the increase of inductance when the internal resistance of loudspeaker is offset by negative resistance circuit, and the adjustable range is between the frequency of open circuit and the frequency when resistance approaches 0 and no inductance is added, that is 98-278 Hz; When the natural frequency of the shunt loudspeaker is matched with the sound mode of the pipeline, the corresponding sound pressure level can be reduced by 8-10 dB.