Sub recommendations - vienna acoustics Bach grands

I just purchased some Vienna Acoustic Bach grands and would like to get a sub that will match them well and not over power them. We listen to music 60 pct of the time and movies 40 pct. I will be adding a maestro as a center channel. Driving them currently with an Onkyo tx-nr 709.

What would you recommend that I consider. Room is 23 x 23 with 10 foot ceilings and we listen to a wide variety of music.

You're gonna need a big sub for that room, think 15 iinches or more. It might be best to go with something like thw Velodyne DD or Optimus Series which have room correction hardware/software.

You can find some pretty good deals on used Velodynes here on Audiogon...

Bonginator, Vienna Acoustics speakers are quite generous with their bass response. Bass response will bloom progressively during break in. I recommend that you break in the speakers completely at least up to the 1000 hours mark, and only then evaluate any requirement for a subwoofer.
Take a look at the REL sub woofers, plenty of models and price points and they can be setup to use with music and high level inputs that are adjustable separately as well as a direct input connection for movies. It is the best sub woofer I ever owned and it was a small one to boot!