Subwoofer insight.

Hi Ric,

I believe what Mr. ieales is trying to tell you is that REL subs are more difficult to integrate into a system than other brands of subs because they do not have variable phase adjustability. Phase in this case basically means that the output signal of the sub starts (or maybe I should say arrives at the listening position) at the exact same time as the output signal of the other speakers (including any other subs) in the system. In a single box speaker this is all controlled by the internal crossover. With a sub woofer and satellite speaker setup that crossover does not exist so that phase/time relationship between the sub and the main needs to be controlled in a different manner. One of the easiest and probably most economical ways to achieve this is by adding variable phase control to the sub amplifier.

REL's phase control allows you to vary the start of the signal in two increments where as other manufactures allow you to vary the start of the signal in as many as 360 increments.  It's kind of like using a ruler with markings at 0", 6" and 12" rather than using one that breaks down each inch into 1/32" segments.

Why REL does not include variable phase adjustability with their subs I do not know, I have a couple of guesses, but ultimately I do not know. OTOH there are a lot of very satisfied REL owners. So what does that mean? Who knows and for that matter who cares. I do know that you don't always need to measure to 1/32" to get the job done but if you can usually the end result will be better.

The bottom line is, do you like what you are hearing? If you do, that is all that matters.

MiniDSP could be employed to integrate the subs if one wanted to get more involved than a simple setup. https://www.minidsp.com/

That is a big room, you got anything smaller, you can treat without getting the partner upset? Does it have to be that room? There is no fix without room treatment of some kind, or just use part of the room, Can you use partitions? Fold out while in use and back when not. Servo bass? OB servo bass, pressures the room a whole different way.  If I had a room that big, there would be at least a 1000 lb of speakers, just for the mains and another 1000 pounds for bass units. That put it in better perspective...BIG room, BIG speakers, more work...

Regards

A lot of overly complicated, unnecessarily redundant information being spread around here.  MORE IS NOT BETTER!  Insanity may dictate otherwise, but keeping it simple makes it easier to control the Q in your listening room.  Quality, fewest connections possible and patience with the setup will go far.  REL Speakon connections are THEE best way to add a subwoofer to your system for 2 channel quality sound reproduction.  Use “LIVE” recordings to dial in the presence and atmosphere that your system can deliver.  REL has very good placement advice, but experimentation is key...corners are bad!  Mine faces front and is roughly in line with the mid driver on my main speakers.  Your room will dictate which is best.  Use bass heavy acoustic music to dial the sub in, repeating familiar tracks till you are satisfied.  It’s actually not that hard and fun to do when you have some extra time to tweak:)

I did not say REL are junk. They have moved into the HiFi Jewelry market adding things which do nothing for the sound and leaving out things that would.

Phase
=====
To get low end out of a small woofer requires adding EQ to the amplifier which adds phase shift and group delay. Sound has magnitude and phase. This is why an out of phase pair of mains sounds the way it does. The amplitude is the same, but the phase is 180° out. The VECTOR sum is zero except for driver and room anomalies. So to integrate a sub, one needs both level and phase controls for the best VECTOR sum. A 180° polarity inversion is the equivalent of moving the sub ≈14 feet @ 40Hz. And a different distance for every other frequency.

Note that a phase control is not a perfect solution, it's just that it's next to hopeless without it.

See http://www.ielogical.com/Audio/SubTerrBlues.php for further explanation.

Tube Amps
=========
The REL instructions are either written for or by someone with ZERO understanding of output transformers.

Google stereophile phase in Images. Notice how the impedance rises in the low end of most speakers. With an output transformer, when the load impedance rises, SO DOES THE OUTPUT VOLTAGE. Since the REL SpeakOn input is high impedance, the sub output will increase due to the increased voltage even though the amplifier input signal does not change in level.

For the gazillionth time, roll the low end from the mains with a simple 6db/oct passive xover about ½ to 1 octave above the mains -db frequency  and drive a sub with multiple XO slopes, phase and polarity controls into the LINE input.

Follow the interface guidelines under Setup at  http://www.ielogical.com/Audio/SubTerrBlues.php.
There are links to model your room, main and sub placement. REW https://www.roomeqwizard.com/ also has good modelling.