Well, this is a tough one. I would also recommend 2 smaller subs for speed and balance in the room.
The JL Audio f110 is -3db at 25HZ, so if you go the JL Audio route I think you would at least need the f112 which is -3db at 19HZ, since your Maggies are already -6db at 31HZ, according to your measurements.
I would think two JL Audio f112's would be the right size for you in this particular setup, however I'm not saying that they will keep up with Maggies, actually nothing probably will, but at least they'll have a chance.
However, I'm thinking of going another route. How about the Wilson Benesch Torus Infrasonic Generator?
http://www.avguide.com/review/wilson-benesch-torus-infrasonic-generator-subwoofer
http://www.wilson-benesch.com/2005/02/torus-infrasonic-generator.html
I've never heard these myself, but you must admit they do sound interesting.
Although, not as fast as your Maggies, I have a pair of Kharma Mini Exquisites, and sometimes I would like a little more bass, however I live in a Condo, so I don't think my neighbors would agree, but if I did add a sub; the Wilson Benesch, Kharma (for my purposes only), JL Audio, and REL would be on my short list too.
I've owned a REL Storm in the past with a pair of Sonus Faber Speakers, and although the REL's are musical, I also didn't think that the bass was fast and tight enough for me. Possibly, the larger, more expensive ones are better.
Martin Logan also has a pretty decent less expensive Sub, that has three fast 8" subwoofers in one box, that have to keep up with their panels.
.
The JL Audio f110 is -3db at 25HZ, so if you go the JL Audio route I think you would at least need the f112 which is -3db at 19HZ, since your Maggies are already -6db at 31HZ, according to your measurements.
I would think two JL Audio f112's would be the right size for you in this particular setup, however I'm not saying that they will keep up with Maggies, actually nothing probably will, but at least they'll have a chance.
However, I'm thinking of going another route. How about the Wilson Benesch Torus Infrasonic Generator?
http://www.avguide.com/review/wilson-benesch-torus-infrasonic-generator-subwoofer
http://www.wilson-benesch.com/2005/02/torus-infrasonic-generator.html
I've never heard these myself, but you must admit they do sound interesting.
Although, not as fast as your Maggies, I have a pair of Kharma Mini Exquisites, and sometimes I would like a little more bass, however I live in a Condo, so I don't think my neighbors would agree, but if I did add a sub; the Wilson Benesch, Kharma (for my purposes only), JL Audio, and REL would be on my short list too.
I've owned a REL Storm in the past with a pair of Sonus Faber Speakers, and although the REL's are musical, I also didn't think that the bass was fast and tight enough for me. Possibly, the larger, more expensive ones are better.
Martin Logan also has a pretty decent less expensive Sub, that has three fast 8" subwoofers in one box, that have to keep up with their panels.
.