Trance,
I spent about 18 months auditioning, researching and finally integrating subs into my 2 channel system. Here are some things that I learned along the way.
(Where judgements are involved, all are IMHO)
Even though one great sub may well have better deep bass output capabilities than two good subs, two good subwoofers will almost always outperform one great sub for music - simply because:
a) Placement flexibility of 2 subs allows you to site them where their room cancellations do not overlap. The result, if you take the time to do that right, is smoother bass response.
and
b) Most music will not really test a single good sub, let alone a great one. For most music, a sub that's designed for 30hz at your preferred SPLs in a space similar in size to your listening room is plenty good for music.
Usually, that means one good, solid subwoofer is sufficient to produce all the clean, deep bass you need for music, but 2 subs allow you to better deal with room induced frequency irregularities. In sum, smoothing the room trumps deep bass output capability for most music applications. Again, MHO.
Of course, your particular taste might be one of the few exceptions (also see pipe organ fans) to the "one sub is enough for clean, deep bass" rule, however, depending on your room size and preferred SPLs.
Note: The statement re: "clean output" assumes relative insensitivity to THD in the deep bass region. You don't want to see THD #s for most subs below about 30hz. At high SPLs they are almost uniformly horrible. The better models from JL, Genelec, and SVS are among the few that really handle that test. Most models from the other popular makes (REL, Velodyne, etc) produce poor test results for THD below 50hz, or so. Fortunately, as FR drops and distortion increases, I find myself less able to hear the problem. I once used two Velo 8" subs in my system. At or below 40 to 50hz at my usual SPLs, test results indicate that they were probably producing as much THD as signal, but it wasn't really distracting to me. Until I substituted superior subs into the system, anyway, then there was no going back. YMMV.
One other note, I also believe that JL makes a GREAT (not just good) subwoofer for music and that the 112 and 113 were hard to distinguish from each other in the medium large room in which I compared them.
So, IMHO...
1) go for 2 subs
2) Two 112s are almost certainly more than up to the task
and
3) When Aldavis says RELs measure notoriously poorly, he is being kind.
Some other things to chew on:
Test results are available for most models on line at HTshack.com Check them out - a little data never hurt anyone.
Given budget considerations, I chose a pair of Rythmik subs, which are great to a little below 35hz at very high SPL in a very large space. This is plenty for my taste in music. They can't match the JLs down in the low 20s (tho they will handily outperform most REL models in this frequency range), but are much less expensive than JLs. A pair of these is probably sufficient for your needs, too, but with the usual "trance music" caveat.
SVS makes a great product that is suitable for your application, more reasonably priced than JL and IMHO definitely worth checking out.
If you can hadle the cost of two 112s, go for it. If you're working to a budget, a pair of SVS (or - to a possibly lesser extent - Rythmiks) will probably outperform a single 113.
As to integrating Subwoofers effectively for music:
a) provided that the subwoofer is properly damped for use use with your main speakers (usually, tho not always, this means a sealed design)
and
b) assuming that you are crossing high enough to keepp the main soeakers in their "comfort zone"
seamless integration has less to do with the particular sub and more to do with placement, crossover characteristics, and phase matching. For this purpose a sub controller is tremendously helpful. I use a Velodyne SMS-1 (and a NHT X-2 to low cut my main speakers and keep the SMS out of the main signal path). Unless you end up with truly mediocre (or worse) subwoofers, the SMS-1 or similar device (Audyssey and SVS/Audyssey market competing models) will allow you to acheive great integration.
Good Luck,
Marty
