Room Treatment experiment

I have a listening room that is big and accoustically live. It is also the main living space for my family including a very esthetically sensitive wife. (see my system). I would like to start working on room treatments but before investing the $$ for something such as echobuster system, does anyone have any cheap or free ideas for getting a sense of what acoustic absorption would do for me? I have tried puting blankets over windows and over TV but don't notice much compared to changes in equipment. My guess is where I now suffer is in the area of a clear soundstage with precise instrument placement.
Thanks
Joe