The thin, foam things may help a little, but barely. Anyone can make really cheap but really good looking panels. OC 703 is good to use in those. Ideally, you want the panels installed so the absorption parts are an inch or two off the wall. This allows absorption on the way in, to bounce off the wall behind it, and absorb it again on the way out.
Focus on first reflection points to the MLP. Side walls and ceiling and floor (thick carpet). Diffusion can be just as important.