Until now, choice has been limited when it comes to in-wall/in-ceiling subwoofers. In fact, the only things those models excite are wall vibrations - not a good thing in a custom subwoofer. But now you have real choices for real bass performance. A minimum of two PCS subs must be used in each system but the more the better! Using two subs randomizes the standing waves within the room so that bass is distributed uniformly. Two or more subs also ensures lower distortion (not that you will hear much distortion with a Paradigm sub!) but at very high output levels, you will be surprised how clean and clear bass remains. A single Paradigm X-300 Amplifier is designed to power two, three or four PCS subs!