I was looking for wall composition for my home theater project to be able to make a budget. I wanted a decent level of noise reduction so I needed information.
I found this site [http://www.stcratings.com/assemblies.html] that gives STC ratings for different wall composition. It is very interesting to see how you can reduce sound going in or out of your theater.
Note that these STC ratings a estimated for 125hz and up…they don’t count for low frequencies (bass). I read that the best solution for bass is to decouple the walls from the rest of the house.