Ka7Nig, for room treatments, start with bass traps, then is first reflection points. It will make a HUGE difference. You can make your own or use RealTraps or GIK. Both are excellent products.
FWIW.. When I was going to make some panels out of rigid fiberglass, I stored the materials in the family room corners till I got around to it. I finally got around to making the panels and taking the stuff out of the family room. The next day my wife told me something was wrong with the stereo in the family room and "it sounded wrong". It was just that the fiberglass was acting as bass traps.