Hoffman's Iron Law states that the efficiency of a woofer system is directly proportional to its cabinet volume and the cube of its cutoff frequency. What this means is the most powerful subwoofer systems are necessarily large.You can probably match your tops with a small sub, like a direct radiating LAB12 in a 4ft3 box. It will go pretty deep, the tradeoff is efficiency for size. But if you want deep bass and high efficiency, you have to use a larger bass bin than that.