Advice for Sub to match with Martin Logan Monolith III


Looking to add a sub to my Monolith III's,  like to keep it around $1,500 new or used.

Thanks,

Steve
stevepa
Old school is hard give up!  I've haven't made the jump to digital movie.  Having a degree in audio  engineering, I still go for  straight music. If I had the budget I would love to listen and watch movies in killer sound.  Knowing myself I would spend way to much money, so I kept it to music only.  An addiction I have to control! :), as you know. 
Yeah, me too. Like I said, I'm 95% two channel music. Maybe having a pair of nice subs will allow me to consider horns or panel speakers next as well. 
A lot of panel speaker owners use Vandersteen 2Wq subs.  New list is around your price range, although I bought two of them used a few years back for under $800 each here on Audiogon.  I don't have panel speakers, but I love these Vandy subs.  A great value IMHO.