I have been tossing around the idea of doing an IB enclosure but I have one problem, Im renting my house currently. The good part is my landlord is pretty open to me doing things to the house as long as I don't do damage or as long as I repair any damage I may cause. Aside from this I most likely will be buying the house from him but it wont be for at least the next year or so. Any way my question is I was wonting to do a set up using 4 15" Dayton IB subs, the only problem is I don't wont to have to make such a large hole for the manifold. Im guessing using these four drivers the manifold would need to be around 18" square & that makes for a pretty good hole in the ceiling. So is there any way I could taper it down so to speak the opening to say around 12" or so without affecting performance to much. I'm thinking that the worst that could happen would be to get a chuffing noise like with a port but I'm not sure. Any ideas would be great. And don't worry I do intend to get full permission from my land lord before I do try anything. I would just like to keep patch work to a minimum if I should decide to not to buy the house. But as its looking I'm going to be here for awhile so I figured what the hell.