The biggest thing one can do to a room without impacting it too much visually is to treat the corners for echoslap. I own a bunch of Roomtunes corner traps, and a number of years ago, before adding Realtraps - which are amazing but intrusive - just treating the corners with those tiny Corner Tunes made even talking in the room much better.
That being said, I personally love bare hardwood floors with no rugs. I am now thinking I may try a rug just to see the effect.
That being said, I personally love bare hardwood floors with no rugs. I am now thinking I may try a rug just to see the effect.