How did that W7 sound in that box...? only reason I ask is because they work at full potential in a 1.25 cuft sealed enclosure (plus speaker displacement and bracing) and I can't see that being much more than 0.75? They are really fussy subwoofers...
I can't see that JL App on an iphone giving you a very accurate analysis of a system being the iphone microphone probably costs 2p to make where as a proper RTA mic costs about £200.... But i guess it gives you a guide!
Why was a center speaker added? this is a cheating way of getting a center stage and actually ruins stereo SQ.