Wow, you guys actually listen at reference levels??? That is waaaay too loud for my ears!
The problem with a 1600 ft^3 well-enclosed room is that there may be some frequency response anomalies that may not be present in a deeper room. So even if a single subwoofer can fill the space easily, one may get a significantly better result with multiple subwoofers...
The problem with a 1600 ft^3 well-enclosed room is that there may be some frequency response anomalies that may not be present in a deeper room. So even if a single subwoofer can fill the space easily, one may get a significantly better result with multiple subwoofers...




















He actually has a couple VTF-3 HO's and a couple MBM's. and is just expressing interest in wanting to listen to many different subs.
That said, maybe later down the road you can accomodate one or two more ULS-15's instead 

