I do hope you are able to come to an acceptable solution. I use a REL B1, one unit, and it blends beautifully with my Sf Cremona Auditor Ms. A true sw should be felt before being heard, part of the room pressurization they are designed to do.

Yeah, it’s a bit strange, I get plenty of very deep low bass as well as the “pressurization” that REL is known for using the low level inputs. It’s just that they insist that the high level input is the way to go so I really want to try it to see how well it works, I just always chalked it up to not having a “ big enough “ sub. Well with the 212SEs that’s definitely not the issue, so I know now that something else is going on.

- Buck

BUCK, here's more info from REL in case you didn't see.......https://relsupport.zendesk.com/hc/en...ced-Monoblocks

Ron

With 2 B2s you should have ample bass/sub-bass support regardless of input. This sounds like a crossover, amplitude or possibly phase issue. I've tuned in lots of RELs in my time and have owned B1s (having demo'ed B2s as well). You can definitely find a batch of settings that will work. Also, make sure the B2 is set properly to expect high-level input....the Mode selector switch for high-level input should be set to '1' or '3' for Line 0 degree or Line 180 degree phase depending upon your setup. It's also important to determine whether you need to go into the High-Level Balanced or Un-balanced Neutrik connector input. The volume setting is also a different dial (I'm sure you know this) for High-Level as opposed to Low-Level inputs on the B-series.

Sometimes there are connection issues with REL when connected to fully balanced, or dual differential amps. The issue is finding the correct place to ground the sub. Try connecting the blk. wire to chassis gnd. or to the gnd. side of your amp's RCA input. If these two locations don't fix the issue leave the blk. wire disconnected and run a separate wire from your amp's RCA gnd. to the sub's RCA input gnd. .

I know this is a bit of an older thread, but here's what happened......as soon as I got the D'agostino stereo amplifier in the setup, I hooked up the RELs the exact same way using their neutrik speakon cables. Clean powerful bass ensued! Absolutely no problems. I can only chalk it up to the McIntosh MC 402.......this is the only amplifier I have ever had (up until the S250) used with REL subwoofers and all of them had the same issue. They only think I can't figure out is that I've spoken to 2 dealers and other users who have never had any Mac issues with REL subs so I have no idea what the deal was. All I know is that with the Dag amplifier, there is no issue. Weird.

- Buck

For REL setup experts
 

Buck - not all McIntosh amps have the same output configuration. Your 402 like my 602 has fully floating transformer outputs that aren’t referenced to chassis ground anywhere.

So the REL speaker level hookup just doesn’t work in this case. It’s a REL design defect.

REL needs to use balanced differential inputs for their speaker level connections which would solve the problem completely and simplify user hookup. Other sub manufacturers do exactly this.

You’ve found a pretty high class way around the problem! :)

Tom

I'm not familiar with the grounding scheme of your new amp. Hope I wasn't too technical, simply put grounding is the key to proper operation. Some amps, like my Levinson, have two ground circuits, chassis gnd. and signal gnd.. Signal gnd. is 10 ohms above (higher) chassis to prevent noise from degrading the input signal. So I had similar issues. This is not a defect, just requires a different solution.

I would argue against a design fault. The fault is not including comprehensive grounding instructions in their manual. I'm confident a REL sub can operate correctly with a Mac. 402 using an alternate ground connection.

+1..

Call REL, they can walk you thru it...(to OP)