I could be wrong but according to my calculations it comes out to a tuning frequency of just a butt hair over 21hz. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gifOriginally posted by 85ss the box is 2.5 cubic feet. The port is 4 inches diameter and 27 inches long.