Wool Blankets as Room treatment

My friend has a giant American Flag. I suggested he put 1/2" thick textured carpet pad behind it.

example, search Bed Bath and Beyond, many exist

Mohawk Home Felt Rug Pad 1/2" Inch Thick Plush Comfort Cushion - Grey - 5' x 7'

As @kijanki said above, they will only help with a very narrow range of problems.

Quite a few materials, that are thick and heavy, that we can barely blow air through, are completely transparent to entire ranges of audible frequencies. So, those ranges of frequencies, will just reflect off the wall as if the wool is not even there.

But it is possible (and probable), that absorption is not all that is needed.

Diffusion in the right places is just as, if not more, important.

I would suggest posting your question over on the DIY Audio forums, in their room acoustics forum. Many very knowledgeable people over there, with the expertise.

Wow some great suggestion here. Thank you.

One of the things I did that helped was use QUIK-TUBE® Building Forms and covered them with dimpled fleece fabric and put those in the corners. You can see them in my profile system photos.
 

Made 4 pf them for <$100

I have done this is my ultra high end listening room a blankets or throw rugs work wonders for a room or speakers  that are bright. I found that it is helpful to reduce the energy from the bass vibrating the dry wall ( which is what sound waves are, energy)  I used a foam mattress pad behind some of the ones I use.. 

let us know and don't believe the BS.