Provided is an acoustic loudspeaker comprising an enclosure and at least first and second loudspeaker drivers. The enclosure comprises at least one tubular sound channel of a substantially constant inside dimension acoustically coupled to the at least first and second loudspeaker drivers. The at least one tubular sound channel comprises a first opening disposed at a first end of the at least one tubular sound channel, a second opening disposed at a second end of the at least one tubular sound channel and a third opening disposed on the at least one tubular sound channel between the first and second ends. The second opening comprises a sound outlet for outputting sound conducted through the enclosure. The enclosure further comprises at least one tuning section disposed within the at least one tubular sound channel between the second and third openings.