yeah the free air idea went out in the 90's , if you want a little boom and not take up alot of space do one of the pioneer shallow 12's box is the size of a briefcase , takes 1200 watts and the box is only 5 inches deep , and take the deck lid apart and take the little 4 inch speakers and let the sub breathe through and you will be surprised , works great for my jl 15w3