Here are some pics of the sound baffles that I made. Really nothing to them. 2' x 4' fiberglas panels come finished on one side. You take 2 of them and put the unfinished sides together, then run some wide gaffer's tape around the sides, and you're done. There are ways to mount them to a wall using metal construction studs (the kind that are used instead of wooden 2x4's) as channels to hold them, but for now, I have just leaned them against the walls.
The case holds 8 pieces; enough for 4 baffles.
Here are two pieces back to back. Note the big roll of wide gaffer's tape and the pair of gloves. Although this stuff is pretty well formed, you don't want to handle fiberglas without gloves.
Run some tape around the sides and you're done:
Believe it or not, just placing 4 of these puppies around the room has improved the clarity of sound in the room. I can hear the nuances of my voice better, and the guitar sound is clearer too. The harshness is gone from the sound in the room.
Here are the sound absorption properties of the tile I used (3155). Note that the 3155 is relatively uniform in absorption across the frequency spectrum and that foam is represented in the last column, and that it has a narrower range of being effective:
Could the same results have been achieved by stapling carpet all around the room? I don't know. Haven't done an A:B comparison. These baffles are lightweight and easy to move around or take out of the room, if I ever want to.
Such a long, long time to be gone, and a short time to be there...