Distributed Bass Array configuration

soundspectacular:" Please correct me if any of my comments here are incorrect as I don't claim to have any expertise. I do believe you are misinterpreting the "term" - "stereo subwoofers". It is a "term" not a sonic phenomena or an implementation in any recording process."

Hello soundspectacular,
 
     You are correct, "stereo subwoofers" is just a term, perhaps only used on this audio forum, that does not represent an actual phenomena or an implementation in any recording process. 
      I consider stereo subs a misnomer since I don't believe stereo bass even exists below about 80 Hz, iwe all perceive it as mono.  But others on this forum believe stereo bass below 80 Hz does exist. 
     The whole stereo bass subject on this forum, unfortunately, only gets more complex and polarized from there, as well as too involved to easily summarize.

Hope this helped,
Tim
     

A lot of the challenge is that while there is no stereo bass in the bottom octave or two, it does sound as if it is stereo. The drum whacks in Bird on a Wire, each one has a definite location. The hall ambience and cannon on Tchaikovsky 1812 are all incredibly precise. When people think of mono they think of Beatle's and other mono records where the sound all seems to be coming from a sphere in between the speakers. That is NOT what we are talking about! This bass does not sound as if it is mono. Not at all.  

However, rest assured, it most certainly IS mono! Anyone harboring any doubt whatsoever is welcome to come and hear, I am happy to demo, and you will hear absolutely zero difference when my DBA is run mono vs stereo. Zero. Nada. Zip. None. Because it is all mono! 

This actually even makes sense, because when you think about it, how else could it be? The wavelength of these low frequencies are so long, that in order to be picked up as stereo the microphones would have to be located a hundred feet or more apart. Even then, our hearing simply is not sensitive to timing at this degree of precision at this low a frequency. We don't even hear less than a full wave! Don't even hear it! 

This is where I think a lot of this comes from. Everyone is familiar with midrange and treble. Everyone knows the importance of phase, timing, etc. This is all goes right out the window with low bass.  

Also by the way with ultra-sonics. Super-tweeters, 40kHz, 60kHz, we cannot even hear. Yet they affect the sound in such a big way it changes our perception of even low bass!  

The mind is a strange and endlessly fascinating thing. Hearing is not just mechanical. We like to use a microphone as a metaphor for how we hear. But that is not all there is to it. The phenomenon of hearing is far more complex. The mind plays a vital role. Try and get your mind around it. 

One thing to keep in mind: if you are using a sub (or four) with---I would certainly hope ;-) ---a low-pass filtered signal as its/their source, well, what is the slope of that filter? If only 6dB/octave (1st-order, as with the Vandersteen subs), that sub reproducing a, say, 80Hz signal, will be reproducing 160Hz (an octave higher) at only 12dB down. Who thinks a 160Hz wave cannot be located in space? How about 320hZ (24dB down)? Naturally a higher-order filter will change those figures.

If you run your sub(s) in mono, that mono output will extend further up in frequency that the frequency at which the x/o is set, the degree to which is determined by the slope of the filter. It is for that reason that some prefer employing higher-order filters (both high-pass and low) to integrate speakers and subs.

Doesn't surprise me at all 60ish khz effects bass perception...at that level, it becomes a 'physical' thing that likely vibrates your body hair...:)
Since you exist daily in an atmosphere soup, the reproduction of those fq adds to the 'reality' of the program....the suspension of disbelief...

I'll agree that L/R bass exists until the 'mono-ization' occurs, and it's all one motion due to wavelengths.  I like the concept of SWARM; smaller drivers quick enough to follow an amt...or a walsh. ;)

The thought of 'off the floor' placement in a smaller space (or a problematic one) has appeal...esp. looking forward to a new and improved place to hit 'reset' on my 'equipment'...*S*

(No recommendations, please. I agree with your selections; mine would likely bore or abhor but please me Enough.)

No, this is not occuring over this weekend.  I have important sloth to indulge in....plenty of time to run simulations.. *S*

-26db....*damn*  If fans bug you, your heartbeat and breathing are next..
Just teasing...don't stop. *g*

Happy 4 to all, play loud enough, J

Based on my experiences running a sound system, years as a bass phreak and a lifetime's work on my domestic rig, i can state with certainty that the ultimate bass is achieved by realising that bass is a part of the music, and should emanate from the same location, travelling in the same direction.

Sound is a pressure wave, and humans are capable of discerning the source of frequencies well below 20hz, let alone 80.
 Place one powerful subwoofer, crossed over below 40hz asymmetrically in a decent sized room and you will clearly, undeniably feel a difference in pressure coming from the side of the room with the sub.

I have enormous respect for the dba as a means to achieve excellent bass operating within parameters like cost , space and waf. 
But the ultimate, and most natural-sounding bass will be achieved from using main speakers with sub 20hz output, and stereo bass stacks sited alongside your main speakers, and firing in the same direction.( I go with a span's width between sub and main speaker.)
Furthermore subs need to be outside the main speakers if you plan on listening from the centre, and for most genres of music i bring the subs in at 40hz. Some dub reggae or deep house tracks get 54hz, but this can sound too thick with other tunes even of the same genre.

 In a nutshell, you have done all of the hard work deciding the best place to put your main speakers. In an ideal world, place your subs next to them. In a compromised world use the distributed bass array, and experience the enjoyable but artificial three dimensional effect described elsewhere.

In terms of using stereo or mono bass, i generally continue to fall into the same trap of imagining that bass is part of the music and should be treated the same as the main signal. By the time you are adding four or more subs you will have output to spare so there's no advantage to quadrupling a mono signal. However i am sympathetic to using mono bass to cope with imbalances caused by triggering room nodes.