Dayam George.... that's some heavy shit...
Yeah, I had to compromise because I don't have a purpose built "listening" room.
I was able to:
1. Run frequency sweeps of each individual driver and precisely calculate the crossover points. These points were way different from the original points and what I thought they would be. The measurement graphs don't lie.
2. Precisely time align each individual driver to each other. Can't stress enough how important this is. The ability to set the delays digitally is a powerful tool Using the Deer Creek Audio method of time alignment that's aimed at Home Theater, my subs time aligned easily. Surprising, they were very close in time alignment to the drivers in the JBL boxes. Reason being, they're front and center, and not in a corner, beside, or behind my listening position. I got best results running the subs as individual drivers in "stereo" mode and not summed.
3. The final measurement was the "room correction" filter. This is where room sweeps for each channel are taken. Getting the crossovers and timing set precisely beforehand must be done. Calculating it for a flat response and not using a room curve worked best for me. Others state the same in some YouTube videos showing advanced use of REW and DSP.
There were additional setup considerations prior to taking benchmark measurements, such as checking individual driver, speaker cable, interconnect, and amp channel polarity, and running amp gain sweeps to balance the gain.
Right channel and left channel must be consistent through all the components to each driver.
Haven't touched a setting in a long time.
And, it sounds great at very low volumes as well as high. Sometimes I really like those low volumes and ability to hear dialogue for home theater.