ATS is great place to get affordable panels or DIY for most economical. Knauf Ecose with FSK facing (white poly on one side) is best for taming bass and room nodes. Not sure ATS offers the FSK version. I found at insulation supply store. Built frames of wood from box store, thick cardboard or 1/4 plywood backs that come 2x4'. Fabric wrapped. Made 6 2'x4' for about $300. Very effective. Corner bass traps prob better but in my modest room would be too intrusive, visually. I didn't have a first reflection problem.
What room treatment product have transformed your room or audio system?
I've been researching and looking more into room treatment products. Wondering what product really worked for you?