take volume from the box?

It is a sealed box, there are no ports.

  You definately need to take volume out of your box .......If your box is 9-10 cubic feet, Your box is about 3 times to big.........I would build a smaller box, fosgate recommends 0.6 cubic feet per driver ,giving you a total of 2.4 cubic feet net for 4 of those speakers..........Your speaker displacement calculations are WAY OFF , displacment for 1 of those subs is .074 , so for all 4 of the speakers your total speaker displacement is .296 for All 4 speakers . The correct sealed enclosure volume recommended by fosgate for 4 of those speakers needs to be 2.696 TOTAL cubic feet.........If you put those subs in a 9-10 cubic feet sealed enclosure the woofer will likely reach its mechanical limits much quicker than in the correct sized enclosure , resulting in lower power handling ................not good .......hope this helps.

frankthetank81 wrote: I am just about finished on a fiberglass box i am doing for my Grand Am. It is rather large as it replaced my whole back seat. It will be holding 4 Rockford Fosgate P3D210. My Volume on the box is around 9-10 cubic feet. Each sub required airspace is from .5 to .75 cubic feet. From my calculations the subs will take a total about a total of 3 cubic feet away from the box. So in a nut shell i will have about  6-7 cubic feet in my box. So my question are: 1.) Do i need to "take" Volume out of the box? 2.) If i do have to take Volume out of the box, what is the best way to do it?

Good Lord man...... make a smaller box!