If you decide to go active, look for a JBL PRX618xlf, Yorkville LS801P, QSC KW118.
Those are the best bang for the buck sub out there being used in the local club/bar circuit.
If you can only afford (1), it is still better then (2) crappy budget active subs.
From what I'm reading, if I'm going with subs then I can or should stick with 12" mains because the mids and highs will sound better from them.
I'm fairly certain I'm going to go with the DXR12s. You think 1 QSC KW181 (1000W) would be a better option then the 2 Yamaha DXS15s?
One thing keeping me looking at the DXS15s is the space issue. They're more manageable and easier to place since they'd go right under the mains. And I want the bass clarity as much as the bass thump which is another reason for me to consider the 15s over 18s.
Link Removed I'm not saying that there isn't any difference but sometimes it isn't practical to cluster your subs. two festivals i played at this year with PRO sound both had subs on each side of the stage. I'm talking PA set-ups worth several hundred thousand dollars.