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

Right!
So how does it sound?

It can’t be complete  until you do the final tuning to your ears with music.  You have to jump ship on the measurements at some point.  That just gets you into the game. 

@mapman

You have to jump ship on the measurements at some point.

I’m not sure if you’re giving me this piece of advice, because I mentioned (I thought), I’m going back and forth, measurements to listening to measurements, etc. Better measurements reveal themselves in a listening experience that reveals more than I was hearing before and it has raised my standards, both as a listener and in terms of what I knew my room was capable of. It’s easier to give me advice if I’m a "measurementalist" but there’s no way that impression could be fairly assigned to what I’ve been saying. Listening is the final test, because after all, I didn't buy a hifi rig so I could run sweeps!

Are these devotions from ruler flat response something you are hearing that affects your listening pleasure or is it something an electronic piece of equipment is telling you is not correct?

@arrowheadrss Not sure where I expressed a fixation on ruler flat response. That’s not realistic and I know it’s not desirable. I’m treating the measurements as one might treat a BMI reading. If it says you’re obese, well, who knows if that’s the right word, but it’s safe to think that dropping a few pounds is to your benefit.

Did you get a response 
from  The Benzman   ?

hilde 45, relative to Sub Woofer Placement 3 Subs are IDEAL!

Here's my solution for  optimization of results, with 3 subs.  

1) Set of 12 inch, self powered 500 Watt Subs at Far Left & Right of room, set @ 70 HZ Crossover.

2) Single 15 Inch Sub Directly in Center. This Sub Woofer is Fed its signal from a dbx 234S Electronic Crossover set @ 40 HZ Crossover Frequency, & set to SUM Left & Right Channel Inputs, which signal is in turn fed to a Classe 25 in Mono Mode, putting out an honest 1,000 Watts. dbx 234S gets its signal directly from the second output of my pre-amp.

3) Combined with PS Audio BHK Signature 300 Mono Blocks, feeding a pair of Anthony Gallo Acoustic 3.0's, three way speakers.

This combination of Speakers puts out Exceptional Non Boomy Bass with Massive Slam, as the 15 Inch Sub Woofer is driving directly into one, when they are sitting in the sweet spot.

I find the "Single Very Low Bass Sub", summing both Left & Right Bass signals to be optimum for Deep Bass, while not interfering with the music that one plays.

Try it, you will like it!

JI use the DBX Driverack VENU360. It has 6 analog outs (xlr), four which can be used for subs. Each sub can be “tuned” to your liking with delay, polarity, dB gain, off/on all from your laptop, phone or iPad. You can also control your two mains with “Q” control, graphic and parametric eq’s as well as all of the above options. It also has a subharmonic control that can be very useful.
I’ve been very leased with the results.
Did I mention it also has a built-dac? I don’t use it, but it’s there if you need it.