One ting that comes to mind is that, because of the reduced reflections, you are able to hear music better and that is why you might have raised the volume? Also, are the GIK 244 directly behind your seating position? Can you try to move them to the side and then check what happens? I do not have the "Sound Blocks", but play with their placement as well. From experience I can say that placement of the panels makes a huge difference. For example, if I try to place a 244 pane on the second reflection point in my room, then it simply kills the musicality and makes it sound lifeless.
Best thing to do would be to check with GIK themselves.