JL F112/Velodyne DD12/Thiel SS1

I have Thiel SC6s powered by Classe mono Blocks.I want to add a sub to enrich the sound stage.Can anyone tell me which sub would add the most musicality to my system.My listening room is 25x22x11.5,due to windows doors and WAF there are very few placement options.I am considering the JL F112 and the Velo DD12,I do like the Thiel Subs,particularly for placement,however they seem to be quite a bit more money.