I got two jl 12w7 and two I'd 1x1000 jl jx. I will upgrade to the hd someday. First off. The subwoofers get incredibly low. Whole car shaking reiw view mirror fell off in a matter of seconds. So here is the deal. With low long bass lines it sounds great. Like three 6 mafia who run it sounds amazing. But a song with short burst bass like bow down by west side connection the sub distorts and does does not hit real hard. I quickly lowered the volume. The box is not double chambered and is about four cubic foot after port and displacement. It is tunned to 35 hrz. So need some advice. Is it the box or my settings? My crossover is set at 80 -12db. My gain is about a fourth of the way turned up along with the bass boost at 1. Any advice would be great. My past three subs have been sealed and I'm now thinking of going back to that