[adogand6kids]

Wes,

I looked at your pictures and I would suggest that if you go with the four 15" drivers in a rectangular manifold that you consider making your manifold opening into your theater room a bit larger. A guide I have heard quoted is to try to have the area of your manifold opening be equal to the combined area of your IB drivers. I stole the following quote from the "cult of the infinitely baffled" web page.

How big should I make my manifold/outlet?

"This is a situation where bigger is always better. If you don't want to make structural changes, then you must work within the existing framing. This means adapting the design of the manifold. For example, let's start off with standard 16" OC joist spacing. This limits the opening to 14.5" in one direction. One can make a 16" cube and mount 4-15"s in it. This is absolutely the smallest opening possible without detrimental bandpass effects occurring. If possible, a better choice is a rectangular manifold, that's external dimensions are 17.5" X 32", with a corresponding 14.5" X 30" opening".

Also, if you can get away with it, try moving your main speakers off the front wall and out into your room a foot or so. Try to get the face of your drivers in front of your TV and stand.