firing subs

im building a box for a friend using two tens in a 2003 silverado. each sub is going under each seat, but in order to keep them out of the way i need to aim them upwards toward the seats. but in order to get the correct air space the speaker woul be about 1 to 2 inches away from the cushions. will this affect the sound output by alot. all he wants is spl, and i will be porting the box.gcorrea

well in all honesty if all he wants is SPL then tell him to get a new vehicle.   Make sure that you have more then enough clearence for excursion, and yes no matter what being under a seat will effect SPL.   Notice most SPL vehicles are hatchbacks or open cab vehicles2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR

2007 USACI World Champion

2007 World Record

2006 USACI Finals 2nd Place

You need at least the diameter of the port in distance of the port opening to any object, so 2 inches won't make it.  And downfire would be preferable to upfire.