My big concern is sound getting in. R11 is supposed to reduce the ability of sound to travel through walls from room to room. the foam will reduce the echo. By the way Ive found a foam place that sells the conveluted foam in grey for 80.00 for two sheets 80"x100". It is fire treated and used in some of the local studios. I think they will sell me some for 50.00. but I want to get mine Installed before I reccomend it for others.
Can I put the foam on bare concrete in my basement? and while you are here I found an asphalt material for the outside of houses that is supposed to keep noise out, and some roofing material that may be good diffusers.