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.