PROBLEM TO BE SOLVED: To provide an active type noise controllable SLIP type muffler and its control method and in particular, a device for analyzing a frequency of exhaust gas and reducing noise by analyzing frequency of exhaust gas and its controlling method.SOLUTION: This invention relates to a muffler for reducing exhaust noise of a vehicle showing a feature that it comprises at least two or more guides connected to an inner wall of a housing storing exhaust gas in the muffler and having a pipe form in a length direction of the muffler and baffles positioned as plane forms parting an inside part of the housing, having electromagnets on its plane of which spacing is adjusted by a moving signal with current applied to the electromagnets in response to a frequency calculated in view of exhaust gas, the number of wavelengths corresponding to the frequency is adjusted to adjust the spacing of the buffles and the exhaust noise is reduced.SELECTED DRAWING: Figure 1
展开▼
