Need some feedback on the REL 212SE Subwoofer

@bulldogger 
Yes I love the Rel. I mostly now use it for movies as I have moved to a hybrid setup doing passthrough via my 2 channel pre. I still use it for certain records etc. it’s a very musical sub and can deliver deep rich accurate bass IMO. Setup is easy and is rather transparent in the room. I’m only running one tho. I also use a Martin Logan Balance Force 212 in the same room connected to the same gear. Between the two I like the ML better to be honest but they both have their strengths. The ML is a beast of a sub and is VERY musical. The thing with the Rels is they would prob sound much Better in a two sub configuration (two Rels) in my situation because I am using autoformer mono blocks and it’s not recommended to use the Rel sound link cable on two autoformer amps. I have read where people have done it but my amp manufacturer recommends not to so I stick to that. 
My advice is to use the proprietary cable that comes with the sub as that configuration sounds better than RCA and there is no XLR inputs. Which it think would make the sub a little better with longer runs as I have. I do get a bit of a low hum (not groundloop I don’t think) when there is no signal going to the Rel before it goes to sleep. Just based on the documentation in regards to hum they seem to be prone to it even with their cable and you need to sometimes even run a ground to the chassis of an amp or to the ground on a empty rca jack according to the manual. However I find the hum not to be loud or annoying as I can barely hear it unless I’m really close to the sub. 
Overall tho it delivers great bass with the two active and two passive drivers which are positioned in the rear and the bottom. It’s a huge sub. I mean huge as the two front drivers are stacked. I get no cabinet vibration at all which is good and the sub is a solid performer. If you have the space and your room is big enough I think it’s a great buy. This is not a sub for a small room so FYI. It will be over kill. 
Hope this helps. 
Let me know if you grab it. 
-Keith 

@bulldogger 
P.S

One other thing I do like about the sub is that is has separate level control for LFE and line in which is a great feature in a hybrid setup. I can have one one output level for music s d one for movies so that is a great feature for me. I wish my ML could do that. Yeah the 212se is a winner 

Thanks. I may stick with Martin Logan. I've been happy with the brand. I recommended Martin Logan to a friend and he loves his two Balanced 210s. I'm building a new room which is not too big, 20x15x9. Front speakers are Mcintosh XR200 run by a Krell Duo 300XD. They hit bass at 20Hz with no problem. My previous room was 24x17x9 with the two Descent subs. With the new 20x15x9 room do you think 1 Balanced 212 would do it? 

Another great option is the MJ Acoustics line up.

@bulldogger 
So my room is 25x15x9 and and I need two so I would think that two will work just fine for you. Either sub you go with will work. Personally I think the ML BF212 is a better sounding sub in my room with my acoustics. However if I had two of the Rels I would probably be just as happy. My suggestion would be...if you go with a two sub setup use two of the same subs. I wish I had bought two of the BF212s but I got such a great deal on the Rel I could not pass it up. Tough call man, because I really like both. I have considered selling one and buying the matching replacement. it was a passing thought lol. Now that I have finally got things balanced out, and I have completed my acoustic treatments I'm afraid to make any changes.