Does a REL subwoofer make the speakers' job easier?

Rel hi level is incredible. Using Rel for over 22 years still have my Rel stentor 3,s with Extremas. In bedroom using two real 9x with Tannoy mini,s incredible

+1 @hilde45

It continues to blow my mind that big sub manufacturers like Kef and Rel don’t even have a phase dial for exact phase matching. Only two opposite settings? It’s simply bizarre to me. Apparently there’s consensus out there there only the tiniest percentage of people are actually aware of how impactful precise phase adjustment is for integration with loudspeakers, having learned through experience with using precision phase adjustments.

@gladmo I hear you and @bdp24  has written a post on subs for the Ages. Really fantastic.

REL is clearly a good product and they have a very vocal and earnest fan base. As I said, I love my REL sub. BUT, as mentioned in bdp24's post, the ability to adjust phase in a variable way is an absolutely crucial feature for anyone without a dedicated listening room and the dozens of hours it takes to get a sub without variable phase placed. I agree it is just ridiculous for REL not to include this feature.

@hilde45 Thanks for the note! It seems there is a lack of common knowledge on how phase adjustment is performed with a variable phase adjustment.  Maybe I'll write one up on that too.

If I were the type of person to give for-profit businesses the benefit of the doubt regarding what seems to be neglectful, I might think there could be something related to the high level connections that Rel likes to include. I'm not an electrical engineer with expertise in audio electronics design, but maybe there's something innate there with matching phase? In other words, if you use the option for your sub to tap into your power amp outputs or your speaker wire signal, does that automatically align the phase of your sub to within 180 degrees of your speaker woofers, thereby providing some justification for the two position phase switch they use? I highly doubt that is the case, but it's something that has crossed my mind as to why Rel and others others have lacked variable phase adjustment controls for so many years, and still do, even on some really expensive products. Even if that were so, there's a lot of people that want to use the line level inputs, and they should be able to have variable phase adjustment like Rythmik provides... And these companies themselves should provide education on how exactly to perform the adjustment process.

@gladmo: I time after after time see and hear people laud REL for their high-level connection design. Well, Brian Ding provides both high-level AND line-level connections in the non-XLR/Standard Size versions of the plate amp of his Rythmik Audio subs (the face plates of which are clearly pictured on the company’s website)..

But he also includes a continuously-variable phase control, which he labels "DELAY". It provides from 0 milliseconds of delay (0 degrees of phase rotation) to 16 milliseconds (180 degrees of rotation), and anywhere in between. The phase switch included on other subs (providing either 0 degrees of rotation or 180 degrees)---including on all RELs’---is a complete joke, of very little practical value. And is in fact an insult to one’s intelligence.

The notion that a sub doesn't require a continuously-variable phase control because a sub is either in phase or is not is a bizarre one. If your cross-over frequency is centered at, say, 100Hz, both sub and main speaker are reproducing that frequency (the high-pass and low-pass filters creating a slope---a decline in output---of the drivers involved). If the wave from both reaches the listening position at the exact same time, their combined output creates a flat frequency response (when well designed and implemented ;-). If a 100Hz tones reaches the lp with the waves from the sub and main speaker completely out-of-phase (180 degrees of phase rotation, or delayed in time 16 milliseconds, commonly referred to as opposite polarity), the two waves will combine to create a deep null in the response. A smaller degree phase mis-alignment will create a shallower null. This is not opinion, it is a fact, one of course well known for a century by all loudspeaker designers. Speaker designers have to provide the same phase alignment between the bass woofers and midrange drivers in their full-range loudspeakers, so as to create a flat frequency response. The alignment between a sub and a loudspeaker is no different. Why WOULD it be?!