Subwoofer to match Vienna Acoustics Bach

I recently purchased a pair of Vienna Bachs. Currently I have a Harman Kardon amp/tuner..I listen to a variety of music, but also use this setup for home theatre. I am wondering what type / model subwoofer would be a good fit with the Bachs to compensate for the low frequency effects needed for many movies (in the $500-1000 price range).

Any ideas would be much appreciated.
ACI Titan II might meet your need, they have 30-day trial plan.
REL subwoofers work very well with Vienna Acoustics speakers, but I am not sure which one would match best with the Bachs.
There is a dealer in denver who advises REL subs with VA speakers. Once again, not sure which one.Like Nti75, im not sure which sub
You may find a REL Storm III for around $1100 used if you keep looking on this site. Otherwise, there are other RELs that would also work: the Strata and the Q-series, which usually go for less than the Storm III.
I'd add a pair of Vandersteen 2wq's to your short list. Fantastic blend by drawing signal from the speaker level outputs from your amp...but doesnt' draw any power because of input imedance of the sub amp..
I'm currently running a REL Storm III with my Bachs. Of course, your experience may vary, but in my opinion there was a huge difference between the Strata and the Storm. I would suggest waiting for a good deal on a Storm III--really an excellent match.
I have a pair of Mozarts, and my M&K mx350 compliments them very well. Because the Viennas are good with high frequencies, and the M&K has great deep low bass, the separation of sound makes for a utopia of high frequency sound, and that kick in the chest deep bass from M&K. I tested the Paradigm Servo 15 but found that the m&k just pleased me more. it hits hard and vibrates your chest inside your lungs.
Try the James EMB-1000 Very musical and it's very Fast.
This Sub has rave reviews,go on the James website and check it out.
This is one sleeper Sub,I don't think they do much advertising.
Thanks for all the useful options. I ended up with the James sub, which has proven to be excellent for music and movies.