There is one way of separating the system from the room and know for sure "is it system or room?" Set the system up outside in your driveway, far from any walls or boundaries. Set up your seating position in the same place. Repeat your tests and see if you get the same audible effects with level. Its a simple test but an effective one and always a dramatic experience to hear what your [nearly] boundary free system sounds like! Now you can better identify what is a system problem vs a room problem. It's much easier to find a fix when you can clearly identify the problem. Audio problems are so often solved via a process of elimination.
Like Geoffkait said, there are so many different problems affecting system + room behavior that most of us cannot figure out where to start or where to end. It's usually beyond us as the science of it is truly complex and overwhelming. Just from the myriad of answers above it is easy to see that almost any place you start applying a fix yields a difference. But is this difference better or just different? That's the real question that is very difficult to answer without some kind of a baseline, a reference of some sort.
Brad
Lone Mountain Audio
TransAudio Group
ATC USA
Like Geoffkait said, there are so many different problems affecting system + room behavior that most of us cannot figure out where to start or where to end. It's usually beyond us as the science of it is truly complex and overwhelming. Just from the myriad of answers above it is easy to see that almost any place you start applying a fix yields a difference. But is this difference better or just different? That's the real question that is very difficult to answer without some kind of a baseline, a reference of some sort.
Brad
Lone Mountain Audio
TransAudio Group
ATC USA