need recommendations for sub for music

Thanks, folks. I will be able to seriously consider any brand (if second hand) including Velodyne, JL Audio REL or Revel.
I'd appreciate specific models you recommend that are truly musical. Most of my music is from the cable channels. I think I may need something larger than a 12" woofer, though. It is a large area I want to fill. From your responses, I realize I may also need a unit with room correction for sure, so that helps.

The RELs use 10" and work fine. Try to get a Strata or Storm. Stay away from the T series for music. The RELs have a great deal of room adjustment.

jl audio f113.... should be more than enough

Martin Logan makes a nice little 10" sub called the Dynamo. It can be configured to either fire out or down and its sealed, which i would recommend if your room is smallish and/or if you are limited in where you can place the sub.

If you can swing $700-800 you should be able to get a used James EMB-1000. This is a terrific musical sub that will just blend in.

I replace my sunfire true sub mark II with the EMB-1000 and the difference was so obvious....suddently the bass was just a smooth clean extension of my other speakers. The sunfire was always a little boomy and a little muffled. The EMB-1000 is a 10". I then replace the emb-1000 with their 12" emb-1200 just because I found one at an irresistable price. Honestly, there is almost no difference, but that's probably because of my listening preferences.

Admittedly, it's very hard to find a James dealer to listen to these speakers...but I am comfortable recommending them, even if you haven't heard them first....they are that good.