Distributed Bass Array configuration

mapman: " What measurements establish the “improved bass”?  Improved in what way?

Just  wondering.  Is it just more? More  extended?  Flatter response ?  Different frequency curve?    What exactly is different than prior?"

Hello mapman,

     I agree with soundspectacular, that the bass in a room or system does not qualify as improved just because it's louder or there's more of it.  I consider more bass an improvement in an audio system only if it manifests itself in the capacity to accurately reproduce large and natural bass dynamics contained on the source material, whether the source material is music or LFE channel information for HT. 
     My goal for my combo system has always been improved bass quality, which I define as bass that is accurate and natural in tone, pitch and intensity as well as powerful, detailed and textured without any exaggeration.  
     I believe a flatter in-room bass response curve and deeper bass frequency extension capacity definitely represent improved system bass performance.  However, I've never utilized any in-room bass frequency response measurement equipment, tools or room correction hardware/software.  I do believe such gear and tools are generally very convenient and helpful once competent skill at their usage has been attained.
    Since I bought and installed my AK Debra 4-sub DBA system about a decade ago, my criteria for evaluating and gauging its effectiveness in my room and system has been purely done by ear and subjectively.  I'd be interested in measuring its in-room bass performance but, unfortunately, I currently lack the gear and skills to do so
    But I'm not very concerned about attaining the gear and skills for accurate room measurement since I know without any doubt, based on how it subjectively sounds and feels, that it represents the best bass system I've yet to experience in my room and system.  I honestly believe my system, formerly with the AK Debra 4-sub DBA and 2.7 mains and currently with 3.7i mains,  has performed so well that I consider it a somewhat miniature version of Magnepan's $30K, 30.7 4-Panel Dipolar Planar Loudspeaker System, click the link attached below for a description and review:

http://www.hifiplus.com/articles/magnepan-307-four-panel-dipolar-planar-loudspeaker-system-revisited...

     About 3-4 years ago or perhaps more, I attended an in-person, Wendell Davis led demonstration of the 30.7 system at Ovation Audio in Indianapolis.  Of course, the 30.7 was very impressive being auditioned in about a 30'x20' room with 8' ceilings and being driven by a single, very large ss Anthem amp (I forgot the model).  The overall system was very impressive.  Natural and powerful sounding with full range and powerful dynamics, very much like how acoustic music played live and unattenuated, sounds and feels when experienced live and in-person.
     But the most surprising and disappointing impression I heard and felt from the 30.7 demo came from its two very large, 6.5'h x 2.5'w each, what they call bass/ mid bass panels.  To be clear, the bass and mid-bass reproduced by these very large dipole speaker panels sounded and felt very powerful, dynamic, natural and seamlessly integrated with the system's two equally large midrange and treble panels.  But I could clearly notice that the 4 modestly sized, 2'hx1'wx1'd, subs of my AK Debra DBA system inconspicuously positioned around my 23'x16' living room,  roughly equaled the 30.7 system's performance in sounding and feeling powerful, dynamic, natural and seamlessly integrated with my system's two more moderately sized, 6'hx2'w, 3-way and full range 2.7 dipole panels, had a bit deeper and more realistic bass extension. This is proven accurate by the difference in the rated bass extension between the two systems: 20 Hz  rated bass extension for the AK Debra system vs 24 Hz rated bass extension for the Magnepan 30.7 system.  
     Not a huge difference but it was obvious to me the AK Debra DBA system. overall, outperformed the 30.7.  After the demo during a Q&A session, I described this difference I perceived and asked Wendell if he ever considered just paying a royalty fee per unit sold to Audio Kinesis for adopting their much less obtrusive, and more effective, bass array concept using 4 small subs instead of the two very large and dipole bass/mid-bass panels. 
     Too blunt and pointed a question? Perhaps, but he's a big boy so no big deal, right?  He responded with a confused look. a hesitant look around the 20 person audience and a rather quick point for the next question.  I like and respect Wendell but everyone could tell he was awkwardly avoiding the question.  I still wonder why?

Tim

Interesting. I have no doubt more subs set up well is better.  I have 1 Klipsch  sw308 I set up manually with kef ls50 metas using  a sound meter app and white noise to initially set things up to extend the bass to be roughly in  line with all the rest then fine tuned including phase by ear.   Simple and effective. Would never have arrived at the right settings by ear alone.  The bass is just right.  

Hello mapman,

      Funny, I have no trouble optimally positioning my subs in the room by ear, when utilizing the sub crawl method on each one sequentially, but I do have trouble optimally setting their phase by ear.
      I found it was much easier to optimally set the group phase on my subs once I turned off my main speakers.  The proper setting became much more obvious to me once I did this, I just set phase at the position at which the bass is slightly louder, more solid, more detailed and the most natural. 
     Another tip, which makes setting the proper phase on subs even easier to discern, is to temporarily invert the polarity on the main speakers (simply by reversing the positive and negative connections on each speaker's terminals), optimally set the phase control on the sub(s) and then swap the main speakers' connections back to normal. 
      This made a lot of sense to me once I learned that the phase and timing of sound waves are almost irrelevant on deep bass frequencies but critically important on midrange and treble frequencies.  Humans are much less sensitive to sound wave arrival times on deep bass tones than we are on tones over about 80 Hz.

Later,
 Tim

@noble101

I set it by ear initially based on what I thought the rolloff of the ls50 metas would be based on specs and reading and thought it sounded good. But I did not achieve my goal which was to fill in the low octave and leave what the mains delivered fine alone. There was a big bass bump from ~ 40-60 hz that was audible on most all tracks. The sound meter app clearly showed this. Room is not large, only 12X12 with lots of furnishings to help break things up naturally.  My crossover was way too high and the level way too low. Now things sound like full range speakers with extended bass. Much better though that is a subjective assessment despite the fact that the setup measures better now! You can only tell there is a sub on the tracks with extended bass to start with. I have full range speakers running in the next much larger room off the same system (no sub) to compare with.