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
4425
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.)
I would imagine there must be a phase adjustment on my REL's.  However, I would not know where to start.  It would be nice if someone could teach us more about phase and how to set up subwoofers.  Now I wonder if I have mine set up correctly.  All I did was to make sure the volume on my subs were not too high.  When I began to be able to detect them I lowered the volume.  Mine are set at about 40% volume.  

Where can I read about this?  Even phase is a bit complicated.  I am sure it must be related to sound wavelengths and to be able to detect when the sound waves cancel each other out.  When do you know sound waves are canceling each other out in the first.

I am new to this hobby for about 2 years and am anxious to learn.  I have a feeling my system might not be set up at its peak performance.  How do you know when sound waves are cancelling each other out in the first place?

A dealer in town specializes in master setting.  Wonder why people in this group are not discussing this?  Perhaps they don't believe in master set?
The phase difference matters ONLY when it is compared to ANOTHER driver in the acoustic vicinity. It does not matter if the speaker is on its own, or it closely matches the OTHER speakers. In the absence of those, or when the sound from anything else is not significant enough with respect to the subwoofer, the phase angle does not matter.

It is all relative basically :-)