This is not rocket science or, if it is, it's not all rocket science. Of course covering cement is going to make a difference. If you have raw cement and go to wood covering you will notice a diff and it usually will be perceived as "warmer". If you have carpet and pad over the cement and then to go to wood the diff will be much less. Especially if the rest of your room surfaces are "warm."
Do you play an instrument? Take an acoustic guitar and and play 18" in front of tile, glass, concrete poured walls, plasterboard, your living room sofa and the sound board of another guitar. What do you like? Surprisingly many people like bright resonant sound. That's why we all sing in the shower - but that's another story. Anyway, it's not a perfect example of a room at higher volume but it will give you the general idea.
There is a difference in trying to add a "shade" to the sound created by your system with room treatment (floors or walls) and trying to extend frequency response of your system using the room. The later is almost always disasterious because it cannot be controlled (the frequency response curve would be anything but straight.) I repeat, if you do not want a speaker that rolls off at 50Hz buy a speaker that does not roll off there! Then treat your room in a manner so that it will effect all bass and treble frequencies somewhat equally and too your liking.
I remain,