Subwoofer in my systemÂ…

Green Mountain Audio with a sub? I'm thinking I'll need something fast, but maybe not.. I've read a lot of previous suggestions in various forums, but I still don't know what would possibly match up well with the GMA first-order crossover etc. sound. Looking for some suggestions here since there's really no where around me to go audition a lot of different subwoofers.

I have a 2-channel combo with Blue Circle Audio's CS integrated(w/pre-amp output) and GMA Callistos. This combo works well in my medium sized room, but I just want something to fill in that bottom end a bit more. I mostly listen to CDs & watch music DVDs. Looking to spend around $500-$700 new or used, but could possible go as high as 1K.

I'd like to get some feedback here first. thanks!
I'd give Roy a call at GMA. He was very helpful with my integration of a sub with my Callistos. I'm in no way an audio designer, but I don't believe frequencies below ~45Hz will mess with any of the Callisto's crossover sound. My sub begins at 45Hz and rolls off at about 35Hz and I can't tell where it's located in my room. In addition to the help you get from this thread, I'd consider calling Roy and ask for advice. Feel free to e-mail me if you need further info. Good luck.
Looks like I have my answer!

Just heard back from Roy Johnson via e-mail. He suggested the DAYTON 12" Titanic MKIII Subwoofer Kit from Parts Express. He also included a very detailed description of how to hook it up, based on if my preamp outs are active or not. He even had some helpful tips on crossover/polarity settings, and where to place it in the room. How bout that! Not to mention, I gave him a budget of $500 - 1K and he recommends something that cost even less.. Sweet!!

Awesome customer service.