Are big subwoofers viable for 2 channel music?

I have a pair of REL 212s, main speakers with their own powered subwoofers. So far the best sub position has been to place them just a bit beside the listening position, slightly to the rear. Without one of the various room measurement programs everything seem like a crapshoot. 
Not to say they haven't improved the bass and overall presentation, but there remains questions as to whether they are optimized. 

" Tim would you go for 4x rel 812, swarm or dual rs2 / s7012?"

Hello smodtactical,

     I'd recommend the Swarm because:

1.  It'll be simpler to setup since you'll only need to properly set the volume, cutoff frequency and phase controls once on the included 1K watt class AB amp/control unit for all 4 subs, rather than individually for each sub with the other options.
2.   It'll be much more aesthetically pleasing in your room than the other options.  Each sub is relatively small at 12"wx14.5"dx28"h, is supported by 3 conical spiked metal footers, have the speaker wire terminals hidden by being located on the bottom and are positioned with the 10" driver facing, and about 1-2 inches away from, the wall.  Once properly positioned, the subs look like attractive wooden pedestals in the wood of your choice.  You can also utilize them as small end tables if you'd like.
3.  It would probably be the least expensive option, unless you know of a seller who offers large discounts on REL subs.

     Overall, four subs will also perform about twice as well as two subs in terms of bass power, speed, smoothness, dynamic impact as well as the levels of detail and seamless integration with your main speakers.  I'm not certain but believe the 4x REL 812 option has the potential to marginally outperform the Swarm but would be more expensive and require the setting of the volume, cutoff frequency and phase controls individually for each sub.

Tim 

OP must have missed the very first post. Tim and I are on the same page. In fact we have almost identical subs. https://systems.audiogon.com/systems/8367 Main difference is I built mine, with help from him and Duke, while he bought Duke's Swarm. Also I have an additional 5th sub, the Talon Roc. Which is how I know the more the better.

Like the first post said, its not a question of which, its how many, and the more the better. 

Subs in a system are like horsepower in a car- more is always better.

Tim would you go for 4x rel 812, swarm or dual rs2 / s7012?

Hello smodtactical.

     There are many advantages to using 4 subs in what's called a distributed bass array (DBA) system.  Using 4 subs, that are each rated to have a capacity of outputting bass down to 20 Hz, results in no single sub being required to operate anywhere near its limit, the cumulative bass produced will effortlessly and accurately reproduce whatever the music or HT source content demands down to the deepest audible bass frequency of 20 Hz and the bass will be fast, smooth and detailed enough to seamlessly integrate with any pair of main speakers you choose to utilize. This high quality bass will also exist throughout your entire large room and not just at a single designated listening seat.
     You have the option of either creating a custom 4-sub DBA system with 4 subs of your choice or buying a complete 4-sub DBA system kit such as the Audio Kinesis Swarm system for $3K reviewed below by the Absolute Sound:
https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

     Due to the large size of your future room and your desire for high quality deep bass performance, I suggest you utilize a minimum of 2 good quality subs, if you're mainly concerned with high quality bass performance at a single designated listening position and 4 good quality subs if you prefer even higher quality bass performance throughout your entire room.

Best wishes,
     Tim

There was a recent discussion about this in another thread where the OP was an owner of a Gotham V2 SW:

https://forum.audiogon.com/discussions/jl-gotham-f212-v2-vs

Here’s a link to a YT video featuring 2 line arrays of the baby brother in the REL performance lineup which is the 510 and an introduction to the REL philosophy by John Hunter REL CEO.

https://youtu.be/I4KPfVu3toU

REL lineup goes

Reference series
1. REL 25 Reference
2. G1 v2

Performance series
3. 212se
4. 812se (replaced the S5 SHO which replaced the REL S5)
5. 510se (replaced the S3 SHO which replaced the REL S3)

T series

Be sure to listen to the part of the Demo @ 10:45. It’s a quite impressive demonstration of the REL’s ability to integrate with the main speakers.

I have a single S5 SHO which was recently replaced by the 812se. It’s a fantastic performer and I would say the value champion in the REL lineup is the 812se.

Based on my experience with REL, I’d think you’d be elated with the 2 channel performance and also quite satisfied with home theater as well.

I am thinking of 2x 2 stack of REL 812se for your room.
You can call REL directly and they will help you with recommendations.

Besides eliminating room nodes with multiple subs, you also want to integrate seamlessly with mains in both presentation and speed. Your mains will determine where you need to be in terms of sub-woofer sizing.

GLHF!

I'm sorry I mean the 4-10 sub, couldn't edit.

Stack 'em high like the Tekton 2-4 sub maybe?

Ask big greg what he thinks of his Rythmik’s...his SVS SB 13’s are beasts too.  Note that he is using 4 subs.  Seems more is more better!

I've been super happy with the Rythmiks.  I like the servo system and Brian and Enrico have been helpful when I've had questions, even though I bought mine second hand.  I've had a few SVS subs and they are great performers also.

Using 4 subs is great.  At first I only used all 4 in my home theater system, but since setting them up for 2 channel listening I find the music more enveloping and engaging.  On many music pieces where the bass isn't prominent, all you hear is clean tight bass that doesn't draw attention to itself.  When playing something with a lot of bass in it, they come alive and give you the feel of listening to live music.

The mass/speed issue is not real.

What is real is the integration with the room.  Smaller sub = less bass = less problems.

Otherwise, bigger is better. :)

A well treated room, including bass traps, is the best place to start.  Talk to GIK Acoustics for advice.

I had an S3 SHO and returned it.  Had a T9i before that.  RELs are awesome in that they play low and have crazy finesse but they don’t really hit you in the chest.

Check out a pair of Rythmik F18’s for $3700.  

Another interesting option would be to buy 4 Tekton 4-10 subs and do a swarm.  That would be $3200 and you’d have 16, yes, 16 10” subs 😵

Ask big greg what he thinks of his Rythmik’s...his SVS SB 13’s are beasts too.  Note that he is using 4 subs.  Seems more is more better!

@b_limo  which rel are you using?
@millercarbon so you would do rel 6 pack 812s over say dual JTR RS2 or S7201 ?

RELs play really low from my experience.  I’m going to try Ryhtmik next time and see if they offer more punch.  

It's good to have headroom, and with a space that size, having multiple subs will help with that as will using larger more powerful subs. I have two Rythmik F25 subs and two SVS SB13 Ultra subs in my system. I'm really happy with the quality/ quantity of bass in my system. 

I dont have any experience with either sub you mentioned. Both look like beasts! The PSA sub appears to be geared more towards home theater. Which doesn't necessarily mean it can't do music well, but it might not be optimized for music. 

You might get more feedback on subs like those on avs forums or audioholics.

With subs it is not a question of which. It is a question of how many.
https://systems.audiogon.com/systems/8367

Get whichever ones float your boat. Just be sure to get four. Or more.