Seems a little slow and rich even when properly set up by trained installers.
I have never listened to the JL's but I do own a Rel B3. I thought the same thing and finally replaced the stock Rel cord with Nordost baseline (custom made by Nordost to rel specs). That made a huge difference. I hear things that the stock cable didn't reproduce like more information and decay. Speed got better too to blend in better with my Dynaudio C1's.
I have not heard the REL, but I have had great success matching the F113 to my B&W 800 speakers without using an active crossover. I run my B&W 's fullrange and crossover the sub around 50 hz. This sub is so fast and powerful that even in my 40'x25' room, I have yet to find it's limits. BTW, the digital calibration with supplied microphone is a breeze to use. If you
I had the F113, and thought it was fantastic; deep, very very fast and woderfully built. But I switched to another sub and eventually ended up with the Rel B1. I have never found it slow at all, could just be my set up, but I think it's the fastest sub I have ever had. It could be the crossover options are just so much better with the high level amp input. I played with that for a long time to get it right, and I have the Rel set a the lowest crossover point I have ever used with a sub, and it just integrates beautifully. I think the Rel is the best of the many subs I have owned. It's even faster than the Vandersteen 2wq, and that was always my standard for fast bass respose.
I'd be worried that adding one sub, let alone two subs to your wonderful system might overwhelm things. I have a room, almost identical in size as yours, and when I tried to use just one REL Storm sub with my previous full range speakers (Dyn C4's) the bass overwhelmed the room and muddied things up. However, I had good success in the same room incorporating the same sub with other speakers that where not quite full range. I recommend you get an in-home trial or 30 day money back deal before you commit.
I have a REL Stadium III and have only heard the Fathom in a dealer's HT setup. More than likely, The REL will **ultimately** integrate better with your main speakers, but the Fathom will probably work better for "plug and play" and should help improve issues with problematic room modes without resorting to acoustical room treatment.
It takes a LOT of work to get the REL located and setup right and Xti16 is correct that replacing the REL hi-level cable with a better aftermarket one (I like the Synergistic Research Tesla Rel Spec) will greatly improve its speed and transparency. The right power cord is needed too.
However, in my situation, bass traps were necessary with the REL to minimize the "slow and rich" characterisic you describe. Prior to adding the bass traps, I migrated to the REL's lowest crossover setting (A1=22hz) to minimize undesireable bass enhancement (just to get the improvement in soundstaging and ambience). With the traps in place, I can actually tune the rooms bass response surgically with the crossover settings to get significantly improved bass linearity. It was all worth it for me.
The REL will amaze you with its ability to enhance "recorded ambience". When switched off, the soundstage shrinks and the overall sound seems anemic. Don't know if the Fathom does this as well.
Bottom line: If you are open to a lot of tweaking (including acoustical room treatment), go with the REL. If not, get the Fathom.
Hopefully, Teajay will jump in with his thoughts before the end of the day. If you want a quick subwoofer, check out his review: http://forum.audiogon.com/cgi-bin/fr.pl?rspkr&1239128112
I've currently got one Fathom 113 and love it. It was a breeze to set up and integrate. Although the manually says an external Xover is better, I do use the HF trim and cut it off around 40 hz with very good success with my Avalon Indras. I also remove some of the lowest bass frequencies as it can overwhelm my 14x18.5 room. I don't know how much better it would be with an external Xover, but it integrates perfectly with my Indras without one.
I have 2 --JLaudio F113 used in stereo with my stats--have tried summed mode and not as good as stereo --they are fast and are seemless with the stats--sound like real bass and are the best subs I have ever owned --I am sure the Rel subs are quite good--just becomes a matter of preference --good luck--note I do have an active xover
I use 2 Stadiums in my 12.5' x 35' room. I have replaced the cables and power cords but the biggest improvement was using Ready Acoustics panels. They are reasonable and good looking, even my wife likes them. The corner bass traps are essential in my opinion.
I owned a REL Stentor III prior to buying two Fathom F113's for my room which measures 20'Lx15'W. Loved the REL as it has been mentioned blends seemlessly once the proper setup has been obtained. Both are great products. My plan originally was to buy a second Stentor III but had a problem with the internal amp.I called Sumiko who shipped out a replacement and it was fine after that incident.
I have lived with the Fathoms for awhile now and have no desire to return to the REL. Not saying it was a bad sub but with the sheer output of the Fathom's amplifiers alone sold me. Musically they are similar with the nod going to the JL due to it's ease of setup and the ARO feature that helps tame the nasty peak most subs emit in some rooms.I also feel that the Fathom's are faster than the REL. But now we're back to the sealed vs ported debate!
Interesting and timely thread as I just replaced a REL studio III with a pair of Fathom F113's. I was ready to go to stereo subs and had to decide what route to take. I loved the REL and felt it was the most musical bass that I had heard. My challenge was that it was very large, thus more of a challenge to get a second one. I also never was quite sure I had it set up correctly as it related to the amplifier connection (no place to ground it). I also had the synergistic cables which are active and thus required electrical outlets. I ultimately grew weary of the funky connection and I perceived the ability to use room correction would be a benefit. Plus I have speakers going down to 30Hz easily anyway. I also like the smaller footprint. The Fathoms have been in for just a week and they are fantastic. I am able to cross them over very low (40hz) and turn them up pretty loudly. They provide a very solid foundation and my bass is nothing short of astonishing. Great pitch and slam. I'm a believer. The REL could be better, but it may take more than I was able to give to get it there.
I see your system is tilted towards home theater rather than 2 channel. Movies must sound great.
I would hope the JL's would blend into your HT system a lot easier and better than the REL Stentor's which are designed primarily for 2 channel audio.
I have owned a dual Rel, Stentor III. I my room they sounded nicet and roomfilling. The pitch definition was utterly pleasant to listen, but many times it seemed artificial to me. So. I plunged into JL and I now have dual f113. To me they sound more natural, more cotrolled and when, I say when really the score demands it the JL delivers with aplomb more so than Rel. I Never looked back. JL in my room is way better.