Rythmik Vs REL Subwoofers - What to Buy?

I have an L Shaped living/dinning room.  The living room measures 13.5'x18.5' and the dining room measures 10.5'x13.5".  I have a pair of Paradigm Prestige 85F towers along the 13.5' wall hooked up to an ARCAM AVR550.  They are currently placed 8' apart with a 72" stereo cabinet between them leaving 45' on both sides of the cabinet.  This wall shares the outside 13.5' wall in the dinning room.  There are two 3' walls that narrow the opening to the dining room.

I am trying to decide what subwoofers to add to my system.  Three dealers suggested I add a pair of subwoofers rather than adding just one based on my room dimensions and room layout.  I am trying to decide between adding a pair of Rythmik F12 Signature subwoofers or a pair of REL T/9i's or a pair of REL S3's and locate them next to the towers.  However, because of limited space I may not be able to consider the S3 subwoofers, as they will crowd my towers more and it will most likely require moving my towers closer together from 8' apart to 7' apart.  The dealers I have talked to suggested I locate the subwoofers in the corners.    

I have an upright piano along the 18' wall to the right and I would prefier to use just one subwoofer located to the left of the piano located approximately 5' to 6' in front of the right front speaker.  This would prevent cluttering the wall where my towers are located and it would make our room look better.  If I locate just one subwoofer next to the piano, the speaker would point directly into the opening of the dining room.

Could you please advise as to whether to go with a Rythmik or a REL subwoofer?  I like the idea of the Rythmik Direct Servo technology.  The amplifier in the subwoofer has the ability to boost lower bass frequencies at lower listening volumes to prevent fall off.  However, would they sound too boomy?  I talked to a highly regarded speaker manufacturer and he told me if I went with the T/9i's, they rated them to go down to 28 Hz at -6 db.  He told me based on this, they would actually be lucky to play down to 35 Hz.  He went on to say this is woofer rather than subwoofer territory.  I have listened to both the REL T/9i and the REL S3 and I was not able to hear a significant difference in bass extension when they were played with a pair Bowers & Wilkins 702's.  However, I liked the way they blended in with the main speakers.  They were seamless and I swore all of the sound was coming out of the towers.  The problem is there are many recordings that contain bass frequencies of 24 Hz and possibly lower and if I go with the REL's I would not be able to hear anything lower than 35 Hz.  The Rythmik Signature F12's play down to 14 Hz.  The speaker manufacture I talked to makes custom Rythmik subwoofers and he told me the Rythmik subs are the most musical subwoofers he has ever heard.  Rythmik sells only direct and it would be helpful to be able to hear one before making my decision.

I listen to 70% music and 30% HT and my first priority is music.

If you were in my shoes, what would you recommend I do?
C8ae46d2 13a8 4a9e 9672 691de36f1fddlarry5729
“Just wish I could listen to his Rythmik’s before pulling the trigger.  However, he does have a 45 day guarantee“

So what’s holding you back? 
Given the L shaped layout, I would consider using the AudioKinesis Swarm.
Though I use Vandy subs, I have heard very positive things about this system.

I have a pair of F12SE subs (in a 17' x 17' living room) and am VERY happy with them. I've run them both using the speaker level and line level inputs. They have been flawless since I set them up. Can't speak to the REL, but I have no desire to change what I have now.
The F12 sounds like a very good sub and a great value. I feel bad even bringing this up and muddying the waters, but you might also consider a used Vandersteen 2wq sub. It goes down to 20Hz (-3dB) and it’s an extremely musical sub, but I think one of its major strengths is it has a very unique design that makes it easier to blend the sub with your system. Many people have been very happy with the results they get from adding one of these, especially for music. Anyway, FWIW. Best of luck.

Richard Vandersteen came up with a great idea for his subs: feed-forward. He determined the difference between the signal the sub was fed, and the sub’s output. He then created an electronic circuit that provided an inverse signal to the woofer, to eliminate that difference. So the feed-forward signal is static.

The Rythmik Direct Servo-Feedback circuit is an active, dynamic system; it reacts to, amongst other things, the changes in voice coil temperature (the temperature of the coil in ALL woofers changes in reaction to signal strength and driver-cone motion), compensating for that change in temperature so as to keep the output of the woofer consistent. You can read about that and lots of other technical information on the Rythmik subs on the companys’ excellent website.