Abstract: A resonance muffler for two cycle internal combustion engines, with a rotationally symmetric resonator housing (1) into which an input pipe socket (8) is leading and which itself leads into an output pipe (4) containing a muffler, the resonator housing (1) defining consecutively in the direction of flow a diverging diffusor section (13), an optional intermediate section (14) of constant flow cross-section, as well as a converging reflector section (15), the output pipe (4) extending coaxially through the resonator housing (1) and the input pipe socket (8) leading tangentially into the diffusor section (13).