When you are talking about 15" subs, their sole purpose is to move air. This sub does not "slap" but it will "pound". Give it 50 Hz or lower and it will sound sweet. Through experimentation to provide the best acoustics (box, ported, free air), I have found that these subs love to breathe. They love as much air as they can get, give it to them, and they will move it for you. I mounted them in plywood behind my 60/40 fold down back seat which basically turns the trunk into a large box. Hidden from view until I pull the seats down; when both seats are down I get some pretty nice bass that will make the steering wheel tremble in my hands. At 200w RMS (actual) input power each, it seems to be the sweet spot for my setup, any less and they will not sound impressive, any more and they will drown out the rest of my music. I installed a 1 fared capacitor to take the hit of the bass strikes and it certainly made an improvement in sound quality. I am driving them with a Pioneer deck with all the bells and whistles. With some custom fine tuning they can really perform. Overall they are pretty versatile in providing sharp bass for everyday listening and earth shattering lows for when you just feel like making your car rattle apart.