The 2 materials you refer to have completely different functions: paxmate for airboarne sound absorbtion and dynamat for minimizing panel vibration. The latter has little use in a low airflow (low vibe) case; the former can be judged partly by weight -- if it's heavier, it generally works a bit better.
For more into... http://forums.silentpcreview.com//viewtopic.php?t=2651
Of all the stuff meant specifically for computer cases the ones by Muffled Computing and AcoustiProducts seem best. Will know more clearly in a week. Testing in the lab.
I was just at Menards last weekend. Found a lot of heavy rubber matting that would make good sound deadeners. Only has to be 1/16" to 1/8" thick. Thicker would be OK but will add weight to the case. If thicker, then it does not need to be from edge to edge (ie 6 " strip s/b OK for 10" area). Use rubber cement to attach.
look for post by Renod in this forum for more advice.
http://forums.silentpcreview.com//viewt ... highlight=
I bought the Damping sheet. Great stuff!
I bought this stuff before my trip to Menards.
I also bought 2lb 1 7/8" foam (like they used to pack in harddrives) in transit. This is to ABSORB sounds. Still waiting for it to arrive.
http://www.foamorder.com/products.cgi?c ... m=acoustic
I am also planing on building a muffler like muffledcomputing.com, using 9.99 drawer from Kmart and aforementioned foam. Its halfway finished, then I need to glue/rubber cement the foam inside and hang with velcro.
The inner drawer (cut to 3" deep) and will face right and be stapled to outside drawer (left at 7" deep) which faces left.
The outside drawer is cut so the lip will hang onto top and one side of the case. I have high hopes.
Thanks a bunch to Renod!