Thank you Tim, 'Copy' to all you say....
I think a mistake I make in responding to measurement questions, is taking for granted that folks understand common limitations , and reply as if their only question is about best technique. (limitations such as being able to align to only one place unless subs are adjacent to mains)
I mean, I barely even try to align subs to mains indoors in the small rooms I see...I'm almost always far more concerned with how the subs interact with the room and stage.
Placement and cutting out modal boosts with eq get most my attention. If any tuning time is left, I might try to align, but most often I just wing it with a ball park guess based off known 'stacked' timing.
And in fairness to the video that started this thread, he was talking about inside.......and doing more than I usually do !
Ivan, I really concur with the multiple mic learning experience. I had the opportunity to build a fairy large audio room (11,000 cu ft) and spend several years measuring it with bunches of speaker/sub placements. (I still remember the joy in learning what corner stacked labhorns could do hehe.) I set up multiple mics, and used both pink and sine waves. Pink variations were of course large, but the sines blew my mind...could not believe the variations even foot by foot. Ultimately, apart from the fore mentioned attention to speaker/sub placement and cutting room modes with eq, the real gains came from acoustic treatment. Taming early reflections, getting an even RT60, and a few other acoustic techniques made for a great sounding room.
Never could get smaart to work for aligning inside haha....had to go outdoors to learn how to do it!
On the reality of being not able to align to more than one place when subs and mains are separated...
I've found very good alignment with speakers right on the sub, but with subs on the ground and speakers on a stick 14ft in air, alignment of course loosens up moving away from 'aligned to' location.
OK, that's just the way it works..critical xover region will suffer some as you move around.
But what I'm thinking is why not at least minimize the critical region of xover overlap...more than typical....
Why not run as steep a x-over as possible between the subs and mains?
I'm toying with 96db right now @100Hz , and it's kinda cool how bass sounds like it stays with the main despite moving the main around. This is inside, so no real telling till I get outside....and there's also the added delay issue from steeper xover to contend with....so a lot of dunnos still ..
Any experience here? Pitfalls beyond delay?