Best DIY Sound Dampening Materials?


Do you have any recommendations on sound dampening materials for a DIY project? I have a wonderful system, but a not so wonderfully small space (12 feet x 12 feet), and I need to dampen the acoustics off the walls and floor.

For the walls, I'm considering taking 4 inch foam (do you have any recommended purchasing sources?), cutting 4x3 foot squares, framing it, canvasing it and hanging a series of these pictures up on the walls (painting the canvas a slight hue of the wall paint). To keep peace with the girlfriend, I need to dampen my room in an aesthetically pleasing way - yes, she's worth it. So, will this work? Are there better alternatives?

For the floor, I'd like to create a removable 16x16 inch wall to trap and avoid the Allison affect. Am I crazy?

Help ... please!

Thanks
dds_hifi
An afterthought: why not read F. Alton Everest's "Sound Studio Construction on a Budget" or his "Master Handbook of Acoustics", 4th Edition, and, along with seeing a huge list of absorption and diffusion devices, learn how to analyze your room's resonant modes--simple arithmetic, and it will tell you where your problems below 300 Hz are. The "Sound Studio" book discusses all kinds of rooms, some smallish.
Tom nice,

Thanks! I'll definitely get those two books. From my perspective, this is a relatively low cost way to signficantly improve my sound quality. I'm surprised more people don't manage this side of their listening experience.

I'll email you for your diffuser plans.

Thanks again!
I have been told by two manufactures that putting canvas in front of acoustic foam is not a good idea. Apparently the canvas prevents the sound waves from being absorped by the foam. Heard this from Sonex and Immedia-both told me I wasted my money on the foam I put behind two oil paintings.
I have a 12x14 room with 4x4x2inch Sonex on both side walls, front and back walls covered w/oil paintings. Don't have much of a problem w/reflected waves. Use a heavy rug for the floor.
Good luck!