Originally Posted by Jeff Smith

Ok your correct that the pioneer specs say that it will wk in .35-.7 cu ft of air space but that's only after you take out for .06 for the woofers displacement inside the box. Which means you need at least .41 before you put the sub in. I sell and install these subs at work and the best box for the 10" is .66 which is what pioneer recommends. In the .35 box it's we call high bass. It makes a sound like boink (85hz) peak instead of boom (50hz peak) in a car. The older JL 8W6 is a waaaay more forgiving sub that the pioneer in smaller boxes.