which subwofer is better?

All fine subs. REL units in general are excellent and many dealers will say particularly good for music. I don't think you have any downsides with any of these options you mentioned. Just have fun with the process :-)

probably get more head-room and punch at high volumes with the JL subs. I sold Rel in past, which are very musical subs - Not so much slam and power with HT rocking, though.
Personally, I like the combo of musicality and HT slam factor of the Paradigm Servo 15 for cheep money, in a large room. The Earthquakes also fill a huge space, take lots of power, and are pretty tight when setup correctly.
As with ANY sub, however, your main issues are getting the subs set up in the room properly, in relation to the seats and speakers. Get phase wrong, or sit where there's big suck out in the bass, big bass humps and imporperly mated coherence with the mains and it is all a moot point! You'll never have great bass performance...just a big sonic mess of over-bloated bass engery, that's got lots of issues, and negatives, rather than fast, tight, dynamic, extended, coherent bass with slam and seemless integration.
I'd say 3/5ths of the performance is acoustics and setup with the sub (EQ'ing?), and the rest is design of the sub itself. That's bass for you....

Avgoround wrote:

I'd say 3/5ths of the performance is acoustics and setup with the sub (EQ'ing?), and the rest is design of the sub itself. That's bass for you....

I'd say 80%, but that's really just me agreeing with AVgoround and adding a little nitpicking for fun.

If you use Audyssey (or equivalent DRC) in your HT electronics, I'd go for the JLs. They go clean and loud better than most. If you do not have DRC in your HT electronics, I'd go Velodyne DD, which includes the same functionality in the sub's set-up software.

BTW, the Velo DRC is IME rather primitive and MUST be set up manually.
Marty

You need to take the power delivery to your system into account. If your system is on (1) 15 or 20 amp circuit, you'll need another (as in dedicated) line if you want (2) subs like the Fathom 113s - they are 2500 watts each.
I sold my Fathom 112 to a friend and went to (2) James EMB-1200s, because I wanted stereo subs without adding a dedicated line.

"BTW, the Velo DRC is IME rather primitive and MUST be set up manually.
Marty"

Primitive, really? Don't you find it odd that professional reviewers use the Velodyne software to show the effects of JL Audio's auto EQ system and even use the Velodyne software to further EQ the JL and many other brands of subwoofers being reviewed? I've done this myself.

Velodyne DD Plus has three methods of one touch optimization: Self-EQ, Auto-EQ, and Manual-EQ Optimization. There is a major degree of auto optimization within the Manual-EQ program by simply accepting the adjustment. The Manual-EQ also offers actual manual adjustments with eight bands of parametric adjustment between 15 and 100 Hz as well as parametric filtering.

There are also provisions for six different preset settings for things like Games and Theater, etc. But most importantly is the ability to make many of these adjustments remotely from the listening position as well as a simple volume with a numerical readout.

If there is another subwoofer that offers more sophistication and the ability to fine tune to integrate more seamlessly musical with a variety of main speakers please let us know.