Subwoofers

Nice speakers. This one is a no brainer to me as you can get two excellent Rhythmik F12G subs for $1000 less than one of the RELs, and the F12Gs even go significantly deeper as well. I’m sure the RELs are good, but the price differential here is pretty staggering considering that they’ll both likely be excellent in your system/room. JL Audio subs have had reliability issues, so for that reason I’d avoid them given the other solid choices available.  Hope this helps, and best of luck.

Wow, that's a nice large space.  What is your total budget and are you looking for a pair of subs?

my first sub question is always, how do you plan to hook them up and do you plan to highpass? 
 

If you can get past the looks the JTR RS1 the best sub I personally have heard that are not diy monsters. Their lowest low pass setting is 60hz… so keep that in mind if you are not using external controls. I am highpassing mine with a Sublime Acoustics K235.  
 

I am not a fan of Rel. too expensive for round rolled off bass. Their top model are probably fine if you want the looks and have money to spend. My JLs had a lot of failures and I would not recommend the brand. They do sound good though. Rythmic and HSU both look like good buys. 

My room is approximately 20 ft x 35 ft.  I'm using two REL S/510 in a stereo pair.  Using speaker level connections for two channel.  I have the gain and crossover set really low. They blend well with my full range speakers. 

If I turn them up very high, it's too much.  I can't feature needing bigger subs for two channel, but I haven't heard them. 

They don't have enough oomph for home theatre. I have a larger SVS sub that kicks in when I'm watching movies 

The S/ 510 and 812 are excellent subs

@greywolf In a room that size you are going to need two 15" or four 12" drivers at work. I design and build my own subwoofers and I only recommend the brands KEF, Martin Logan and Magico. I think what would best suite you would be two Martin Logan Balanced Force 212s. Balanced force subwoofers have matching drivers at opposite ends of the enclosure working in phase so both cones extend and contract at the same time cancelling out all Newtonian forces.The subwoofers produce less distortion. At this time REL, SVS and JL Audio make nothing like them. If you are going to do subwoofers a two way crossover is IMHO mandatory to get the best performance out of the system

Well Rhythmik has a foam surround, the Martin Logan costs to much. Still undecided.

It looks like you may be selling yourself a little short. With that nice of a set of speakers, I would think a set of REL carbon specials could do the trick properly. Plus, that way as time goes by you can save your pennies and start stacking them for a line array. Or you could just use a pair of 212/sx and be done with it. Good luck 👍 most jealous of your quest. 

Carbons are more than I want to spend. 

what do you all think of this sub 

https://www.crutchfield.com/p_265B1122WA/Revel-Performa3-B112v2-High-Gloss-Walnut.html?tp=187

@greywolf I haven't heard the Revel, but I notice that it only has line level inputs.  Maybe that works for you, but I like connecting the REL with speaker level for two channel.  It also has separate line level inputs for a LFE channel if your system doubles as a home theatre line mine does.  You can use both inputs simultaneously and it has separate gain controls for each.  

I also noticed that the crossover frequency is shown as 50 to 150.  To get my subs to blend, I'm considerably lower than 50. Not sure if that's a problem.

Thanks sls883, two channel system with a NAD M12 preamp with 2 sub outs. Used for TV, music and streaming movies.

Never had a sub with high level hook up.  

The really nice thing about having high level and the LFE input is that I can set the high level output low for music and crank up the LFE gain for movies.  If you are using the subs for home theatre, I think I'd go with the REL S812 if you like loud explosions, etc.  The S510 would work for some people, but I like a little more for home theater especially in my large room.  I don't know if other subwoofer brands will also do this. Perhaps they will.

I lucked out and got both of my REL subs new for under $4500.  You probably won't get a deal like that, but I would guess that some of the larger online resellers would discount 10% if you call them (Music Direct, Audio Advisor, Crutchfield, etc).

Why REL?  You'll get a lot more bang for your buck, and great sound with a pair of Rythmik G25HPs.  With REL you're paying at least half the price of the sub for marketing and dealer markup.  With Rythmik (and other internet direct options), there's not all that overhead. 

If you're worried about the durability of the Rythmiks, I have had my F25s for about 8 years now, and am not the original owner.  They are probably at least 10 years old.  Amps and replacement drivers are still available in the event something were to fail.  

If foam surrounds on Rhythmik subs are an issue for you, why were they even on your list in the first place?  Also, I’ve never, ever heard of anyone having an issue with a Rhythmik sub.  Crossing Rhythmiks off your list simply due to foam surrounds would be a mistake I think given the performance, value, and overall quality on offer, but that’s me.

I have heard and owned a lot of subs and the JL Audio Fathom series are super deep and powerful.  

Honorable mention to the SVS SB3000 which are app adjustable, have excellent impact and a very likeable tone.  

I didn't see that model had foam surrounds, excuse me. 

Maybe it's me but I find Rhythmiks site hard to navigate.

Maybe it's me but I find Rhythmiks site hard to navigate.

Other than adding new products, I don't think they've updated their website in the many years I've been visiting it, but all the subs are listed on the front page.  Click on one to get the specs.  Not hard.

Check out the reviews (e.g. Audioholics) of the Arendal 1723, they have both ported and sealed versions.

I have the smaller 1961 sealed version in my 2.1 bedroom system.  It integrates easily with my Magnepans but still has plenty of oomph for movies and the like.