A connection pipe (7), for the fluidic connection of a muffler housing (5) of an active muffler (4) with an exhaust gas-carrying pipe (3) of an exhaust line (2) of an exhaust system (1) for an internal combustion engine, of a motor vehicle, has a pipe wall (8), which envelopes a connection space (9) leading from the muffler housing to the exhaust pipe. A cooling pipe (14), through which a coolant can flow, has an inlet section (15) and an outlet section (16) and is arranged in the connection space. The inlet section (15) passes through the pipe wall (8), whereby a coolant inlet (17), through which coolant can enter the cooling air pipe, is arranged outside the connection pipe (7). The outlet section passes through the pipe wall, whereby a coolant outlet (19), through which coolant can escape from the cooling pipe, is arranged outside the connection pipe (7).

The present invention relates to a loudspeaker (1; 1; 1) with a loudspeaker housing (2; 2), a basket (3) held in the loudspeaker housing (2; 2) and bearing a permanent magnet (9), a coil (91) arranged in a constant magnetic field generated by the permanent magnet (9) and connected with a diaphragm (5), and at least one heat pipe (10) with a heating zone (Z1) and cooling zone (Z3), wherein the heating zone (Z1) is arranged on the permanent magnet (9), and the cooling zone (Z3) on the loudspeaker housing (2; 2). The present invention further relates to the use of such a loudspeaker for actively extinguishing or influencing sound waves, and a noise control system (100) for exhaust systems of a vehicle powered by an internal combustion engine with such a loudspeaker (1; 1, 1).

An exhaust system for an internal combustion engine includes a muffler, a first exhaust pipe which is connected to the muffler for sound damping, and a second exhaust pipe which extends in terms of flow in parallel relation to the first exhaust pipe and extends through first muffler in the absence of a flow communication with the first muffler. The first and second exhaust pipes originate from a common exhaust pipe. A switching valve adjusts hereby a throughflow cross section of the second exhaust pipe.

Disclosed are methods, devices, apparatus, assemblies and systems for generating and directing acoustic energy (e.g. sound). According to some embodiments, there may be provided a cyclical acoustic apparatus or generator comprising a cyclical combustions chamber adapted to cyclically generate acoustic energy. There may be provided an acoustic energy collection and guiding assembly adapted to channel sounds energy generated by said cyclical combustion chamber to an aiming and release apparatus, which aiming and release apparatus directs the acoustic energy towards a target zone.