Critical subwoofer tip


I assume that everyone already knows the importance of phase matching a sub to the main speakers but it’s a little more complicated than simple 90 degrees or 180. The B&W sub that I have has four choices. In every case there has been a definite correct position that can be non standard. My current setup shined at 270 degrees vs the std positions. It’s completely obvious and the other choices would not have been satisfying. 
From my lengthy experience I would want a subwoofer with several phase choices. I personally don’t see how one could seamlessly integrate the mains and the sub without this flexibility. No one asked but i thought this info might be useful to anyone purchasing a subwoofer. YMMV
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I spent over a month getting my pair of t7i's to even sound like they managed any semblance to bass response. I can assure you if they are completely out of phase with your mains it does make a difference! You want those subs pushing out and contracting at the same time your mains are. I know there's better terminology but I'm listening to Clapton while responding. It was a pain to get it right by ear but you'll be rewarded when you do. If phase wasn't important why would we have the ability to set them? why would there be mfgs designing then with servo auto driven phase adjustments? When I did what REL said and heard when it was audibly louder it was in phase and when you listen again from LP you'll know it. Still fine tuning but getting there and loving the ride!
@golfnutz, great way for adjusting the phase . I learnt it from Barry Oder .
I totally believe in adjusting the phase/timing  to the listening position for the sub and the mains . You can do the same with an av receiver by adjusting the subwoofer distance setting .
I use 2 subs jl audio 113v2 integrated with my magico m3. The rt sub is phase adjusted  to the rt speaker and lt to lt main ,  at the listening position. Changing the phase, the difference is very obvious  as the subs are placed in the optimal position using the crawl method .so the primary listening position is not a null.
I totally agree with the OP .
Don’t see how????
No imagination. Change the vertical and/or horizontal direction of the wave eminence. Avoid down firing configurations.
A phase switch is mostly a decorator option.
I am simply blown away by Millercarbon's knowledge.  He should be teaching at a university.  Fascinating conversation.  Can't believe people have more than two subwoofers.  

I did a lot of research before I purchased my subwoofers.  I was torn between a Rythmik and REL.  However, how can you buy speakers without being able to hear them.  What made sense to me was the high level connection design REL uses.  This allows the subwoofers to act more like large woofers to extend the bass of the two main tower speakers.  I think the trick is to make sure you do not play subwoofers too loud.  If you can detect them, they are too loud.  I read where subwoofers can take some of the load of the main speakers and allow them to play clearer.  Can't think of the correct terminology.  I went with two REL S2' SHO's rather than one think a pair would level out the room and create a more even sound stage.  

I have seen systems with 6 REL G1 Mark II's stacked 3 high on both sides.  To me this would mean there has got to be too much bass.  However, there must be a reason why some use 6 of these with moderate size tower speakers.  I would be curious to be able to hear what they sound like.  They must have the volume set really low.  I think in my case I think my tower speakers sound a little brighter, but I do not know why.  Someone told me adding subs help to take some of the work load off the main speakers so they can work more efficiently.  I know bass speakers draw most of the power.  Having active powered subs certainly are very efficient.  Wonder how all of this works.  Be curious to learn from Millercarbon how this works and why adding subwoofers really helps to even out the sound.  I think it must increase the size of the sound stage.  I would imagine Millercarbon must be a dealer.  He sounds extremely knowledgeable that's for sure.  So many people in this group are so knowledgeable.  However, at times some can respond rudely.  I think if they avoided the put downs it would allow people like myself to know how to ask the right questions without being criticized.

Hopes this makes sense.  It would be nice for this group to meet over a few glasses of wine and not only discuss, but be able to hear their sound systems so we could learn more in person.

Play this demo only with your subwoofer(s) 

https://youtu.be/kUT6ZhFdLkA

If you hear no difference when the phase is switched, the people who think phase does not affect LF sound are correct.

Alternatively, if you sense/hear/feel a difference, phase matters in LF too.

(Play this video full-range and phase change obviously affects spacial cues.)