Floor carpet and maybe a 5 foot thick mattress along the back wall and you're golden. The more homogenous all room boundary acoustic properties are the better.
Guess you replaced your back wall treatment with a 5' thick mattress since your suggesting it ... I'm sure that must of been a upgrade from the furnace filters and fabric stuffing you had there previously ... anyway most of the stuff I read on back wall treatment suggest that diffusion works well in most cases ... an experiment for sure ...
Actually Mojo, I'm looking for carpet ... any suggestions on what type I should look at ...
