Concrete walls

[Twitch9]

I understand the theory of LF waves, i was responding to the first sentance in you post where you did not mention LF reflections, The main reason why you'd want to put up a layer of drywall is to reduce the reflections off that wall if you would have stated LF reflections in this statement i would have agreed and never posted, i was responding to reflections in general with concrete vs drywall and how just hanging drywall would make no difference in how each would reflect sound off the surface area.

It's all good and your post will help people understand how materials can capture sound. It nice to meet other geeks who appreciate sound theory and put it to use.