Bought a new home in April 2010. Have a living room that is 21 feet x 24 feet - peak height is 15 feet. The NHT Xd does not fill the room at high volume and create "Room Lock." Beautiful and pristine sound at low to normal listening volumes. (I`ve heard nothing better) But - in this relatively large room - the NHT VT-3s have NEVER sounded better! These bad boys can move some serious air. They have great "room lock" to say the least. The NHT Xds are very well built. And the best value in audio today period. But not to fill big spaces.