Distributed Bass Array configuration

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.

I did try the Trinnov pre amp, but the Wavac pt-t1 tanned it's behind.
If your system is already correctly time aligned in analogue by having each drive unit the same distance from the listening position, there is nothing to be gained from the Trinnov's digital time correction. The dealer was crestfallen, he could clearly hear the same thing i did.

All that was left was the character of the pre amp, and my preference for a valve pre amp remained intact. Fortified, even.

< 20 - 60 hz is considered SUB BASS. It is MONO, I don't care what you do to it. BUT if there is a left and right SUB bass signal from the source that is replaying via the MIXED recording, you can't just use the left or right signal and call it good. 

I've read here on AG countless times "it makes no difference because its MONO", use either the left or the right output. NO!

You have to use BOTH LEFT and RIGHT signals to play the WHOLE bass track...

Second. BASS is directional PERIOD.. 60 - 80 hz is transitional from SUB to BASS. BASS is 80-250 hz. 

The problem is the decay rate of ALL the lower frequency waves 80 < loading the room and BOOMING.

I went to GRs OB servo system.. FIXED that problem, right NOW! BOTH sided of the cone are in the room. How simple is that? The only place and WAY OB works for ME.
It has a step baffle and a pretty well programmed firmware chip.. Rythmik plate amps.

The other problem is overshoot from 80-250 hz (where ALL the SLAM is).

THAT is where a lot of systems get sloppy from MB to MIDS, they get muddy and OVER-exaggerated low mids.. or bloated? I can't stand when the congas SUCK. or Cher's voice.. :-) A baritone girl or a Contralto (to be correct) sound bad.. 

I direct couple the MB columns to serious class d 12k pro amps.. and use an active full blown DSP XO. It Fixed the overshoot problem for the first time without a (SLOW A$$) VERY EXPENSIVE accelerometer set up.. 1/10 the cost..

There is a difference in SUBs and BASS BUT I keep seeing the TWO used as if they were the same thing.. I use two different drivers for TWO different things.. More floor space but a much bigger smile. :-)

    bdp24,
      The 4-sub Audio Kinesis Swarm and Debra DBA systems utilize a  Kilowatt class shelf-mount class AB amp/control unit with a 4th order variable lowpass filter that rolls off the bass at 3 dB per octave from 100 Hz down to 20.  
     The 4 sub modules have a gentle roll-off across their passband that is the approximate inverse of typical room gain from boundary reinforcement. Typical room gain from placement near a wall is 3 dB per octave below 100 Hz, and so the Swarm modules roll off at about

3 dB per octave from 100 Hz down to 20 Hz.  Here's a link to the system's description and specs: 

 http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

     When utilizing a 4-sub DBA in mono mode, I think it's important for everyone to understand that one is still able to perceive a deep and wide sound stage illusion in full stereo over the entire, standard and audible 20 Hz-20KHz frequency spectrum.   In other words, one is able to perceive stereo deep bass below 80 Hz and localize deep bass instruments in the stereo sound stage illusion.  

     I don't believe this bass perception, however, can accurately be classified as "stereo subwoofers" or "stereo deep bass" since the bass below about 80 Hz is technically being played back in mono.  In all the music source material I possess, the bass below about 80 Hz is also summed to mono during the recording process.

     My theory, about how this mono bass is perceived as stereo bass , is that bass sounds below 80 Hz have harmonics, or overtones, that reach beyond 80 Hz which are able to be localized.  These harmonics or overtones are recorded and played back in stereo through the l+r main stereo speakers. Our brains are then capable of associating these over 80 Hz harmonics/overtones, coming from the main l+r speakers in stereo, with the under 80 Hz fundamental tones, coming from the 4 subs in mono, and creating an overall perception of stereo bass that specifically details where in the 3 dimensional stereo sound stage the sound is coming from in a very natural and realistic manner.  

     My opinion is that this type of stereo deep bass perception is unique and deserves its own name or description, other than "stereo subwoofers" or "stereo deep bass".  I find a fairly low crossover frequency between 40-50 Hz performs best in my room and system for both music and HT.  Even though I know the bass is mono, I definitely perceive the music as high quality, very natural, very realistic and in full range stereo.

Tim

Tim yes correct. If I walk into a room with somebody bowing the low string on a cello, which is 41Hz, I can tell where it is. If the first 2 octaves can’t be localised then how is this possible?

It’s the harmonic overtones providing the spatial clues and the preservation of these overtones is vitally important to the entire spectrum.

It would not be possible to locate a signal generator producing the  same 41Hz .  as a sine wave.