bestbang4thebuck, I was going to order another clock but Geoff Kait, the seller of these clocks, told me that two clocks are about as much improvement as you can get with these before the diminishing returns start kicking in but one person is using three of these clocks, audiogon and audio asylum member Wellfed, this is the person I talked to before buying these clocks. Room size, from what Geoff told me these clocks will work in very large rooms with great effect, they have not tested these to see what the room max is yet. They do not work outdoors at all but they do work in your car really good.