Abstract: For dampening exhaust gas noise a muffler contains two portions, of which one is adapted to take care of high frequency noise and includes dampening material, and the other is adapted to take care of low frequency noise and is devoid of such material. The latter portion includes an inner, perforated tube, a surrounding casing and wall means for subdividing the casing axially as well as transversely. The length of the tube is compatible with the lowest frequency of the noise to be divided, and the location of the wall means is selected as to form chambers of varying lengths compatible with other frequencies within the low frequency zone.The high frequency portion may be fitted concentrically around the low frequency portion, or may be located so as to form an axial extention thereby.The means communicating the low and the high frequency portions may include a radial diffusor.