I currently have paradigm mini monitors v1, looking to upgrade and need help. These would sit on bookshelf just above the TV. For movie watching mostly. These also sit too close together for center channel, so I set the Yamaha v630 non-center which routes the center channel signal to the left and right main speakers. If the receiver sets the speakers to small, do I need to worry if the speakers are rear ported? I have an old paradigm PDR-10 (also need to upgrade). Room is 15x18x12 feet high. How do you know the bookshelf speakers can "fill the room with sound"? Thanks!