Current room is open, not treated, many windows--in other words, an acoustical mess. But still I manage to mix well as I learn more about the room (past year only). I am going to build a new studio building, so it will be much better when that is completed. And at that point, but sub will most likely be a great addition. My biggest problem is always having too much bass in the mix, due to not having a sub and having small monitors, but I've learned to compensate for it pretty well finally, after a lot of practice.