Now put the cab direct to the hardwood and see what happens. If you are on pier and beam the whole floor will become a soundboard and probably give you yet more bass (but possibly induce some extraneous noise into your recording). If you're on concrete slab you might get a bit more treble or it might just remain neutral. Regardless, I always like a rug in front of the amp to reduce some of the sharp, biting acoustic reflections coming off the floor. What's weird is my floors are straight concrete slab, no flooring, but my ceiling is vaulted so I don't have those harsh reflections even without a rug.