Hey guys, new to posting on here. Been looking around a long time. Anyways the old velodyne hgs-12 just crapped out and decided to do my own build. I really need someone to help me with size of tube and port size as I own only android stuff and can't get any programs to work. What I have is an 18 inch sonotube 6` long, Dayton reference HP 15, and several pro audio amps. Probably will use qsc 1450 and dbx crossover. Very capable of the build but need some guidance. 60% music the rest movies. Thanks