I'd like to say that I appreciate all the help and patience from individuals on this forum. My sonsosub has actually been done for some time, but I've had problems with the amp connection (hum) until recently. When I inserted a line level shifter (takes the -10dBv output to +4dBu input of the pro amp) things seem to be working wonderfully. However, the signal is still very weak, I have the amp (mackie 1400i, 1400x1 @4ohm) at full gain and it's not 'terribly' loud. The weird thing is that the mackie is barely even detecting a signal (the signal present light flickers on and off during music playback, not even to mention i have to turn the volume on my receiver (onkyo integra DTR7) to about 40-50 to get the amp to register -20dB input. That aside...on to the review: INCREDIBLE! I didn't know a vented 15" sub could sound so tight. What really surprised me is that I have, up until now, owned a Velodyne VA1215 (sealed 12 with passive 15), and this thing is even MORE musical than that! But the best part is the bass extension. I'm able to pick up sub 20 hz frequencies that were apparently not screened out when the signals were recorded. I never thought that a sub this large could integrate this well into a pair of B&W 602s as well. FYI: It's a single tempest in a 260 liter enclosure tuned to 20 hz.