Setting up stereo Rel subwoofers….

I started with 1 REL sub, which I set up as perfectly as I could...when I added the second, placement was relatively easy, one of the benefits of dual subs...the key to placing the second was asymmetrical placement ,  guided by Duke L (AK Sub Swarm)...some depends too on bass of main speakers...mine are large floor standers with good bass...adding the second sub was even more beneficial than I had hoped...

If you have room, REL recommends putting each subwoofer just outside of each main speaker.  If that doesn't work, set them just inside of the mains.  I emailed them and asked them when I was setting mine up. 

For 2 subs, REL recommends placing the subs to the outside (or inside if there's not enough room) of each main speaker. Also, slightly behind the front of the speaker.

Hook them up as you said above. Follow REL's instructions for making adjustments to the crossover and volume on one sub at a time (disconnect or turn off the other sub).

That's how it's done according to the manual for my pair of T5x and it worked perfectly. Not sure if the procedure is different for other models.

Connect Rel stereo subs with one to Right and one to left channel. You will need to tie the red & yellow together for the + and the black to the -.. If there is a ground hum you may need to float the ground(s). If you can't adjust the sub volume past 1/2 way you can untie one of the + (Red or Yellow). You can find this info on Rels website

Connect it to one channel only.  I don’t think there is any reason not the connect both subs following the placement suggestions from REL though and then moving subs if needed.  The original placement of the single sub might not be optimal once you add the second anyway.

First, are you using high level inputs?  If so easy to connect the R to the Right amp inputs and the Left to the Left amp inputs using high level wiring, which I recommend.  As said, this is all on the REL website.  Different amps (class D) require different wiring.  For my class A/B Audionet amps, I use the Red and Black to the inputs on the amps and float the yellow wire.  For the crawl testing of only one sub (maybe this is what you are asking) I don't think it matters much and I would just connect it to one side as this will be the final wiring.

@jastralfu

If he sets it up the way REL states like I posted above, the subs won’t need to be moved, the only thing he may have to do is adjust the subs volume down slightly.

REL will have you moving the sub around during set up if you only have a single unit, to take advantage of boundary reinforcement because of the lesser output.

@newfzx7 i agree, that’s why I was questioning setting up a single sub then adding the second.  Do both at the same time as REL, and you, recommend.  I did end of moving my REL subs arrangement though into an asymmetrical placement that works better for my room.

Thanks for all the replies. I did the crawl and found 2 spots for the a T 7x’s. It was noticeably louder and bassy. One was in the corner, one to the left about midway between listening position and speakers. I may try both out side and behind the main speakers just to compare but that defeats the purpose of the crawl. 
2 questions: how

may “clicks” on the crossover do you have?

And did anyone disconnect the yellow wire for less output ? I have plenty of bass (sounds great/ Mofi Sourcepoint 8 btw)

th and!

I have two REL, easiest setup for subs, have to be inside speakers as I have Klipschorns.

Clicks or crossover point will be highly variable per speakers and room. I disconnected yellow on both, excessive bass with both red/yellow/signal wires. I also have monoblocks so this may have role in this.

["Been moving my sub about to the right or left of rig for months. Still not happy turn it up and midrange gets smeared turn it down and punch just drops. So finally broke down and did the floor crawl thing with sub in listening position. Son of a biscuit it worked. Really didnt want it in this position but it sounds so much better.

How many people end up with it here?

128x128jbuhl11-30-2024 11:33"]

["REL subwoofers (I still like our original term Sub Bass System for its more complete description of what we do)"]

Locating and positioning a subwoofer within a rooms standing wave bass modes using the subwoofer crawl is the first step with actual subwoofers. Despite REL using Richard Edmund Lord's term in the above clarification that their products are actually (-6dB) Sub Bass Systems, jbuhl11 clearly benefited from bass mode positioning.

In my short time with a large REL I found it also benefited from the bass mode position as well as using the preamps direct L+R low level XLR connections.

Down loading a low frequency cadence is more convenient for the crawl than track #4 on the Sneakers album. Good luck with your setup. 

In home theater setups, I placed the subs near the corners for maximum gain/bass. For audio, I placed the subs out into the room, once behind the speakers, the other times on the outside of the main speakers. I never wanted to actually hear big bass, just a better over all fullness with clean bass

Hi @jastralfu 

If he sets it up the way REL states like I posted above, the subs won’t need to be moved, the only thing he may have to do is adjust the subs volume down slightly.

REL will have you moving the sub around during set up if you only have a single unit, to take advantage of boundary reinforcement because of the lesser output.

I did not find this to be true in my basement.  With two Rel Carbon Specials just inside my main floor standing speakers, I got significant boom from right behind me (I have a wall around my utility closet right behind my couch).   For me, moving the subs well outside my speakers into the corners of the room, asymmetrically pointed, the room nodes smoothed out a lot and the booming decreased.  I also added bass corner traps in various corners of the room which also helps.  Now people can not even locate my subs, but they add significantly to air pressure and soundstage of my floor standers, running full range.  To allow me to have flexibility on placement, I run my subs with REL's wireless system which is fast and seamless.  Of course I still go through the adjustments of phase, frequency adjustment and volume.  It is set and forget.  For demonstration it is easy to click the wireless senders on and off.

If the position of the duel subs will allow, don't overlook option to make high-level connections directly to respective speaker binding posts vs amp.  REL has a YouTube video on same.

@fastfreight , using two subs, how do you connect them to the wireless sending/receiving units?  Thanks.

Here’s how it went, to this point. I just twisted both red/yellow wires together, hooked them both up, and left one off to do the process.The crawl seemed to work in that there did seem to be a couple spots where the bass seemed full, louder. That provide a lot of bass for sure. (I may go back to it, try it again). Then I set them up just outside the main speakers (Mofi 8’s which go down to about 47hz afaik).

I wanted to try the way REL suggests and see if it integrates well that way. Yes, it does sound great- I only use the system for music. I have the crossover at 13 clicks, the vol at 15 and only using one wire. I tried to get good bass but not too much, kind of integrated smoothly. One thing was: I could not tell which PHASE was better, they both just about sounded the same. Not sure how big a deal that is... I may try 2 wires again but I want to be able adjust the volume a few clicks.

And I don’t know if 13 crossover clicks is perfect for the MOFI’s or how far that is- all that I saw suggested was the lower is better.

I do think this has turned these excellent speakers into the best system I’ve ever had, easily. I run an Eversolo A8 and a Musical Fidelity M6si.

Hello @doni ,

My REL Carbon Limiteds came with the REL Longbow Wireless Receivers built in.  Here is from REL's product description page:

Finally, you can connect to the Carbon wirelessly, using REL’s Longbow transmitter, featuring the same functionality and inputs as the ones on the rear panel of the Carbon. This eliminates the long cables from amplifier to subwoofer and has a range of about 45 feet. You can read the full definition of the Longbow system here, but suffice to say it’s the easiest bit of hardware we’ve ever used. Two switches, and you’re done.

As we’ve mentioned in other REL articles, switching back and forth between the Longbow and wired connections reveals no difference in the character of our reference system’s LF performance. The receiver is built into the Carbon, but you will need a transmitter, which has a cost of $300. The Longbow can control up to four separate REL’s in mono mode, but if you want to run a pair in discrete stereo mode, you will need two Longbow transmitters.

The Longbows work great, and placement becomes imaginative instead  of limited.  I tried so hard and long to put my subs just inboard of my main speakers, and went through two brands of subs because of the boom.  Now they are way outside of my main speakers, actually along the sidewalls.  Take a peek at my system photo...those are my amps inboard of my speakers and the subs are out of view.

BTW, you can add REL wireless to most of their subs, they have a few systems, model dependent.