Which Sub. Rel B-1 or Fathom F-113

Not true, the Rel subs are more musical and also faster. They integrate better with high end speakers. If you are going 2 - channel get the Rel. Nothing loads a room better than a Rel! I dont think you will need the brute force of the JL, which is better for high SPL. BTW, there is absolutely no port noise.

You have to try them both. The Rel will win because they are fast enough to keep up with you Martin Logan's and disappear into the background.

Obeobgyn, HAVE you ever tried a Rel subwoofer???? I have tried a JL and the REL... and the REL won in MY room in MY system. Not all subwoofers are the same and integrate well in all rooms. I have a small room and the JL was too much, too sloppy and too boomy. It didnt sound good at all. The Rel blended perfectly. Have you tried some aftermarket cables as well? I'm using a Synergistic Rel spec speaker cable which works wonderful, better than any sub cable I ever tried. It really brings the performance to reference quality.

You have a big room and big speakers so I'm thinking the JL worked better for you, but you will not know for sure unless you tried a REL. Rel's biggest are the B1 and Stentor III and Studio III sub, have you tried any of them in your room????