Exhaust muffler for internal combustion engines

A muffler comprising:

• a shell defining a shell cavity, the shell having a shell longitudinal axis, a shell first end, and a shell second end opposite and spaced apart along the shell longitudinal axis from the shell first end, wherein the shell first end and the shell second end each define a shell opening extending to the shell cavity;
• and
• a tube assembly disposed within the shell cavity, the tube assembly including three or more nested tubes, each of the three or more nested tubes having a tube longitudinal axis parallel to the shell longitudinal axis, a tube first end, and a tube second end opposite and spaced apart along the tube longitudinal axis from the tube first end, wherein each of the three or more nested tubes defines a plurality of perforations,
• wherein the three or more nested tubes are disposed circumferentially adjacent each other around the shell longitudinal axis such that portions of sides of the three or more nested tubes form an open portion extending along the shell longitudinal axis.