a tube having an entrance port, an exit port axially displaced from the entrance port, an axial flow channel extending from the entrance port to the exit port, a plurality of expansion chambers each extending radially from and in fluid communication with the axial flow channel, and an outer wall enclosing the axial flow channel and the expansion chambers;

each expansion chamber enclosed by an inner surface of the outer wall and by a plurality of internal walls that each extend from the axial flow channel to the outer wall;

wherein the outer wall is integrally formed to each of the inner walls; and

wherein the expansion chambers comprise a plurality of groups of axially stacked expansion chambers, each group of axially stacked expansion chambers axially offset from and overlapping an adjacent one of the groups of axially stacked expansion chambers.