Just a quick note to add: a couple of years ago we have installed plastic laminate flooring on the main floor of our house. It works fine looks and durability wize, but the acoustics is terrible, even though we used high quality underlayment. There is a lot of sound reflection, making everything more muffled: the TV has to be turned way louder than before just to be heard 12 feet in front, and yet in the rest of the house the TV sound is way to loud. The same with the music.

I would suggest that any smooth surface floors should be covered for better acoustics. It won't matter if all you are doing is recording yourself play directly from the keyboard, but if you are using any sort of a microphone, either for vocals, or acoustic instruments, the acoustics will make at least some difference.

Regards,
Alex