more low end response, especially if you listen to lots of rap with thick bass lines like 36 mafia or any of the dirty south rap, ugggghhhh. My box is tuned to 33hz and man it kicks. Up in the 45+ range is just usually tuning for comps. The best thing to do is contact DD tell them what you have and what you want to do and they will tell you everything, like tuning freq, port size.