So I scoured craigslist this morning to find some 8'x4'x3" fiberglass panels for sale at $20 per. I wasn't really intending to build any in the near future, but at the price, I went ahead and picked up all 11 he had for sale (couple for me and the rest for other local polkies I gave a heads up to). This is my first venture into this arena and would appreciate any do's/don'ts or any other advice that could be shared.
I plan on putting one full sheet behind my projector screen. Another Polkie shared w/ me the mirror trick about first reflections, so I'll be doing that. Where else do I need to address? I assume I would need some directly behind the listening position? The room is 12x14.