Muffler device

The invention refers to a muffler device for installation within an exhaust pipe (2) connected to an engine, said exhaust pipe (2) having a cross-sectional inner area (A 1 ). The muffler is arranged to shift a resonance frequency carried by engine exhaust gases passing through said exhaust pipe (2) in a flow direction. The muffler device comprises an obstruction device (7) placed within the exhaust pipe (2). The invention is characterised in that the obstruction device (2) has a projected area (Ap) in relation to the inner area (A 1 ) such that the standing wave frequency for an open pipe is shifted into a standing wave frequency for a closed pipe with a minimum back pressure.