So i'm building a big box to replace the 3rd row in my yukon that will hold 2 12's, amp rack for mono and 4 chan, and then also add some powered rear fill firing between captains chairs (4"s) and some rear firing 5.25 2 ways to fill mids and highs for listening out the tailgate... say when tailgating... the box will essentially be divided into 3 chambers, one on each side for each sub and one in the middle for all wiring and other nonsense, the additional speakers will be on the front and back of this middle chamber which will probably be somewhere around 2 cu. ft.... my question is do i need to enclose the area behind the speakers(like make a small enclosure inside the larger one)? or does this middle chamber act as a free air situation? if i don't enclose the smaller speakers will I have big cancellation problems even though the speakers are small(they will be about 2 feet apart firing in opposite directions)?