Best Speaker "Flooring" Material for the house ?

I have been reading some different things and might call Rives or someone, but what is the best floor to have in your listening room?
-For example you start with a concrete slab, Do you Pad and carpet...
-Or first lay some floor boards(Plywood, Mdf?) and lay the pad and carpet.
-Also have heard about CORK being used and most effective, if so How?
-Pergo/Floating fake floors?
-Hardwood?
-Mainly I have heard most rooms that I like with bass fairly heavy, mostly thick carpeting, but what is the best way?
-Just comment on how you would build from scratch a dedicated room floor the layers, order, and materials used.
Thanks