Meh, that could be a possibility..I think while im there I will get a reading with the box rotated both directions to make sure.
And since im in NW...the rear deck is pretty much a giant hole, no carpeting and I modified it previously (theres metal cut away from the center of it...the 18 is pretty much firing straight up into the cabin)...i also will have the rear seats taken out for comps...so with no rear seats, no rear deck carpeting, and some of the rear deck missing I think that'll help me quite a bit