What process did you use to integrate multiple subwoofers for 2 channel listening?

https://ohmspeaker.com/news/for-optimum-sound-how-many-subs-and-where-do-you-put-em/

One other thing. I know audiokinesis is big on speaker dispersion patterns and how that affects the sound.
Seems to me that benefits of a bass array is not the same in all cases. Mains need to have good dispersion characteristics to start with to match the subs I would think for best results. If mains are highly directional, there may be only so much to gain from smoother bass response across a room. Or it might just make getting things to sound right across the room impossible to start with no matter what you do with subs.
Food for thought.

@tvad Thanks. I didn't know I could do that. Makes sense. I was under the impression that MC invented the DBA and Duke just happened to be selling it. His system page puzzled me because it seemed like I should be seeing Duke's stuff in his room but then I realized he made it himself.

@hshifi Thanks for your input. I'll try the crawl again but with three subs, I better get my knee pads. Another vote for DSP -- thanks! As for bass traps or diffusers, I have many -- 4 Mondo Bass Traps, 2 GIK corner traps, 2 GIK Q7 diffusers, 4 GIK HF limited bass traps, 2 DIY absorbers 4" thick, 2 ATS bass traps, 4 ATS absorbers. I've also made several more pillows (e.g. a giant dog pillow stuffed with R38). I've moved everything around everywhere and measured all the while. Dozens of hours or more. I've moved huge amounts of furniture and even brought in more bookshelves for more diffusion. Plus, so homemade deflectors home made from wood boards to tweak reflections.
Hiring someone may be the way to go. I understand how multiple subs are supposed to work and how bass waves move in the room. It's now a question of discovering what's efficacious, given all the factors.

@powemi Good point. I will use my ears. I'm developing a sympathy between measurement and listening. The reason I am mentioning the bass hump is that I can defnitely hear it. The problem with using one's ears for a deep null is that one may not realize very easily that there is missing information, because we tend to fill in the blanks with our brains.

@mapman -- exactly. It's the complexity that makes a sub crawl or just using my ears hard to fathom.

SO the one thing that should be gained rather simply with multiple subs no matter what is that each sub now has to work less hard to provide the proper bass level and as Duke alluded to in that original post as provided by Tvad, that alone should be a positive to some extent in that most amps sound better when they do not have to work as hard. How much better? I suspect YMMV there case by case.

So more subs are better than less, but you do have to get them all working together properly somehow. You can’t just assume well its bass so location does not matter. Nothing truly worthwhile is ever simple, right?

Also it will most likely never ever be perfect still. Just better. Something no self respecting audiophile is ever likely to find easy to accept. It can always be even better, right?

Where does it stop? You get to decide. I’ve stopped at just one when needed (only with limited range speakers) and 0 with full range. The most I see myself ever going if I convince myself I need more torture and clutter someday would be 4 based on what I’ve read to-date.

Yup, I knew I would end up with a pair of subs.  I am a big fan of the Vandersteen subs.  I think their unique design makes for excellent integration and easy placement.  They are designed for corner placement (why isn't every sub designed to sit in a corner?).  I had to buy used, so there was time between the first sub and the second.  The first went in one corner behind and outside the right speaker, the second went in the other corner behind the left.  A little tweaking of the level and Q controls (crossover is fixed at 80Hz, first order), and I was enjoying deep, tight stereo bass that sounded like it all came from my mains; these subs never call attention to themselves.  Fantastic!  I have the discontinued 2Wqs, but the newer model has a built in EQ, which should make it even easier.  

Rat-shack sound pressure meter, test LP and lots of experiments with positioning of the two dual 18” DJ subwoofers