Well I am going to purchase a D2 15" monday and I needed some help on building an enclosure. On the website it says that SI reccomends the box be 4 cu/ft vented to 28 hz. I was reading around on the forums people doing like 2.1 cu/ft boxes ported to 30 hz. Whats the deal with this? I love deep deep bass but also like a bit of SQ in the mix. I will be running the sub off a hifonics bx1500. What do you guys recommend I build? Thanks