[bpape]

The 175 kg/m3 will work for bass control but is overkill. Something in the 40-80 range will work fine. Also, the thicker you use, the less density you can get by with.

As far as the cost/Sabine, that works to a point. However, doing the 8" thick will yield better control at the bottom end. So, you'll get more 'targeted bottom end' Sabines with the thicker material vs 2x the surface area. All depends on what part of the room you're addressing, what else is in there, what it's to be used for, etc.

Bryan