I think that if the DBA system is integrated properly it affords one the
ability to integrate bass effortlessly, no matter the listening level,
which is highly appealing to me.
The beauty of DBA is the "integrated properly" happens almost automatically. With one sub it is impossible, the peaks and nulls are unavoidable and draw attention to the bass. With four they are so small and smooth the bass disappears, the subs disappear, and all you are left with to "integrate" is their level.
When it comes to that, there is no escape from the reality of human hearing. Equal loudness contours are a thing. DBA is no magic bullet.
It does however get a lot closer to what you described. With normal no, one, or two sub bass the really low bottom end either falls off to nothing, or else you have way too much above that. Either way you notice big changes with volume. With a DBA the contours are still there but nowhere near as big a problem due I think to the smoothness factor.
What I did, once the initial phase is done, was listen to a lot of different music at my normal levels. I abhor meters. Most of the time I listen at a nice satisfying volume level. Sometimes not that loud. Occasionally I listen Supertramp Loud. Gradually, over time, I make really small level adjustments. Really small. Like I turn the knob but about half the time not really sure it did anything. This works because the meaning of the equal loudness contours is we go from being relatively insensitive to bass at low volume to hyper sensitive to bass at high volume. The same 2dB change in other words seems completely different (a lot more) from 98 to 100dB than from 88 to 90.
Took a while, but most of the tweaking was in the first few weeks and now it is pretty close to what you said, effortless no matter the listening level. Never quite gets there, but close enough I never give it any thought any more- until it comes up like this.
