Subwoofer for Dunlavy SC IV's

Does anyone have any experience or recommendations on subwoofers to complement the Dunlavy SCIV's?

You have not specified a price range for the subwoofer(s), so you will probably get the usual suggestions for the better-known subwoofers: REL, Velodyne, etc. Among the subs you should consider, include the Vandersteen 2Wq (or V2W if you are going to use the sub solely for home theater).

I recommend you audition the Vandersteen 2Wq sub, preferably in a stereo pair, for the following reasons:
1. the Dunlavy speakers are time and phase accurate, as are Vandersteens, so you will preserve this important aspect of your main speakers performance (the 2Wq has a 6-db, first order crossover);
2. the 2Wq crossover connects between the preamp and the power amp (whereas the V2W is driven from the LFE outputs on the pre/pro), so the subwoofer receives the signal from the power amp, thereby giving the entire system the characteristics of the main power amp;
3. the 2Wq allows you to adjust the "Q" (damping) characteristics, thereby making it easier to tailor the output to match your room and main speakers;
4. the 2Wq represents an excellent value (price vs. performance).
Can't remember the name, but there is a company that bought the remaining stock & parts from Dunlavy. You might want to check and see if they have any of the Dunlavy subs. These were all pretty big though, so don't know how that would work into your situation if you or your significant other is worried about cosmetics. Then again, if you've already got SC IV's, ... : ) Sean