A straight-through flow muffler (10) is shown. A cylindrical housing (11) has an inlet (13a), an outlet (14a), and a pair of axially aligned, longitudinally spaced tubes (15, 16) extending from the inlet and outlet into the center of the muffler housing. Imperforate baffles (17, 18) separate the muffler housing into a plurality of attentuation chambers (20, 21, 22) surrounding the tubes (15, 16). A pair of sonic chokes (25, 26) are mounted in series in the tubes. The baffles and a pattern of perforations in the tubes cooperate to block flow between chambers except through the sonic chokes (25, 26) while permitting fluid communication between the tubes and the individual chambers.