Polk Audio Psw SUBWOOFERS: Velodyne Impact 12 Or Klipsch Synergy 12 Or Polk Audio PSW 505. Help Me To Choose Please.?

SUBWOOFERS: Velodyne Impact 12 or Klipsch Synergy 12 or Polk Audio PSW 505. Help me to choose please.? - polk audio psw

For use with Denon 889-7.1 (100 watts per channel) My room is about 5x5 meters. Wats How should I feel and hear a hollow well. Please respond. Thank you.