A fluid coupling conduit (6 50 70 104 134) includes an inlet end (28 52 76 110 140) structured to receive a flow of breathing gas an outlet end (32 56 78 112 142) fluidly coupled to the inlet end and defining an outlet opening a central chamber portion (36 60 80 124 145) positioned between the inlet end and the outlet end the central chamber portion having an outer wall (38 62 82 116 146) positioned opposite the outlet opening. The outer wall has a plurality of exhaust gas orifices (40 64 84 118 148) extending therethrough. A number of sound attenuating structures are disposed in the central chamber portion between the outlet opening and the outer wall. The sound attenuating structures including a plurality of surfaces structured to reflect sound waves associated with exhaust gas flow through the fluid coupling conduit.
