Homemade sound panels

While I have the ones that Goheelz mentions, I happen to like the ones from this company a lot better.

http://www.acoustimac.com/

I second Duke: in my experience all the so called anti reverberration acoustical panels make the sound dead. Diffusors do work but in the majority of cases you should use bass traps. There is one caveat though: bass traps are bulky and you'll need lots of them to get significant reduction of room modes. If a room sucks, you'll never get good sound, even with extensive acoustic modifications.

Chris

OC703 is the material of choice for many DIY panels. It comes in 1" or 2" and maybe even thicker 2'x4' sheets, usually in '6 packs'.
You Tube (no kidding) has a couple vids on such constructions.

My plan is to treat '1st reflection' points and the back wall of my listening area. This will reduce the echo type effect while leaving the rest of the room fairly live.

Don't overdo it!

What kind of panels are you talking about? I've made some membrane panels and my only regret is that I didn't make them bigger. 6X3 instead of 4X2 would have doubled the material cost but that's insignificant to the labour and result. Membrane panels are more specific solutions for a narrower band problem.

I guess the catagory would be 'broadband absorbers' or some such. certainly NOT tuned, i would use panels such as I describe to treat excess 'liveness' in any listening area. Placed on the wall between speakers, you may be able to modify the image.
My use will, again, be to damp out the first reflection point of each speaker, Magnepan 1.6s.
My first pass effort will be to make some panels on stands to move around and see....listen actually! If I can make a few specific improvments in image/staging while damping out the back part of the fairly long (25' or so) room, I'll call it quits. When I decide on location....maybe a 4 month project, I'll do a permanent mounting.
Owens Corning 703 is some kind of boiler insulation which has gained a decent DIY reputation in the audio catagory.
I suppose with only a little ingenuity, you could make panels in any desired shape or size. I'll stick to the 'as issued' 2'x4' and multiples of that.

Next step is to find some accoustic fabric....maybe a trip up to the fashion district in LA and see the sights. Since I share the space with spouse, I must consider WAF and even make new drapes part of the negotiations. You can't be too careful!