I downloaded WinISD last night, and after reading the tutorial, I pretty much figured it out. I am considering either the Dayton 15" Quatro ($85 295-560) or the 15" Titanic MkIII ($200 295-420) As a theoretical box, I did 18" X 24" X 24" inside measurements and a 20 Hz. tuning frequency. A single 4" port is also included. They both show ~22 Hz. @ -3dB., but the Titanic, at RMS, had a max output of ~120 dB. while the Quatro was at ~115 dB. - I am in a pretty small room, and that is a small difference, and that $120 difference would be enought to do the project (wood, compoenets, etc.) What do you think? Am I using the software correctly? Am I in the sort of mindset I should be? Any advice? I have a pretty good understanding of audio, but I am still a novice in DIY. ALSO: whenever I do a sealed box design, my -3 dB. point seems to be in the upper 30's, is that about right? Thanks! Also, when I get some $$$ taken care of, I will probably order a pro Crown amp and a Art 351 EQ, so that will be enough to drive it.