I place my subs right behind the seat as well, but that was only after measuring many other locations. I get a pretty good response there. Not only that, but the 'punch' is really something. Localization can be a thing with such close proximity placement, but with two of them, you may be able overcome that if you spread them apart s bit. If such a placement puts the subs near the middle of the room, you will lose much of the low-end room gain, but with two VTF-3s, you will not need the help of room gain at all. You are going to get your ass kicked, and, trust me, it will be great.