I have made rectangular and triangular panels out of 2'x4' fiberglass ceiling tiles and covered them with muslin fabric and a hot glue gun.I also made tube traps out of 4' metal fencing like the type you would put around a garden.I filled the inside with fiberglass insulation,but didn't pack it tight.I left a hole down the middle and then also covered it with the muslin fabric.Not only are these effective but they are also cheap.Good Luck.
Room Treatment
We have all talked about the best amp, best pre-amp and the best audio components to buy at a certain price. I would like to find out what material is the best room treatment available. Is is a hard material like a styrofoam product or an absobtive product like rubber or sponge? What has worked for you and why? Do you use fabric to hide these treatments or have you found something better? Room treatment has very little discussion. I would like to find a DIY project that can improve the overall dynamics of a very difficult room. Let me hear your comments.....