When you say they don't "fill" the room, are you talking bass, treble, or just overall power? Are you talking music cranked up, or movies? Are you incorporating a sub, and if so, have you calibrated everything correctly?
Just trying to understand where they are lacking for you? I know you say you tested them within your enclosure and out, but speakers are reinforced by the walls around them. It appears it is open behind those openings, so in my opinion you will loose some performance.
If you have a sub, are the speakers set to small in the receiver, and are you using 80hz crossover in the receiver, and bypassed on the back of the sub?