Homemade sound panels

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!

My panels frames are 5" thick wood frames with a pegboard divider recesed 2" into the frame.The front part has a 2x4 Metro diffuser(foam)inserted in it.Then the back is a piece 2x4'-2" thick OC705 inserted,& covered with a breathable casing to keep the fibers in..They will be mounted about 4" of the wall to maximize sound waves..What do you think??

Just my opin......I would lose the pegboard. Also, foam doesnt' transmit sound. the object is to either aborb, turning sound energy into heat, or to diffuse/reflect randomly. The 705 will absorb, since it is 'transparent' to sound. If you can't breath thru it, the foam will tend to reflect.
Mounting away from the wall is a good idea, it'll give you incoming and outgoing 'treatment'.
Again, just my opin, but I'd either make diffusors or absorbers. The local fabric outlet has a real open 'fabric' which would be good for covering 703/5 doing as you suggest, keeping the fibers in. Cover the whole thing in accoustic cloth and your there.

As a sidenote, an anachoic space is NOT what you want. I've been in a very dead recording studio and it is ...funny sounding..... Many normal audio 'q's are simply gone missing. Don't do that to your listening space.