Eh hem!...Subwoofers... What do ya know?

So far this turned out to be not another non sense poisoned discussion, seems subwoofers are "a thing to avoid" for the usual trolls,which is great

We are getting now into time alignment, dsp and such, keep it coming, I will take my minidsp mic and rew out of storage and do some measurements on my own system.

Thanks to the OP, I bet the short cryptic title is a deterrent 😉

@erik_squires thanks good info;

I agree the using a pre-out (or active crossover) the preferred way and so does JL audio, but in my case I am running my XLR only DAC directly into my Amp; I will need to play around in the speaker level input regime until I either get an active preamp or the JL CR-1 (preferred);

I actually sold my preamp because I found no real advantage using that vs DAC direct; So, with those funds I diverted into the JL subs and some cables (I digress); Now, it seems that plan was half baked and I would have been better off keeping the pre and stretching the budget to get the subs but I'm already way over my audio budget for the next 10 years, lol

Anyone: please take a look at my setup; do you think the subs should go on the inside or outside?

https://imgur.com/Paj46Ti

-Cheers

I would try everything. Even keeping that position and aiming at each other . You may find only one is needed there and another in the back corner . Take one of them place it on your chair and check the room for standing waves as noted before . Then place the sub where the bass was the loudest. And keep them turned down . Or the bass will sound loose . 

Good idea davekayc
Keep all options on the table!!

The JL E-112 subs have a fair amount of built in tuning so hopefully this proves helpful;

Since I am nuts about this stuff, I am going to grab our nice Oscilloscope from work and my omni mics (or use a Laptop with some USB mics) and capture the onset of various test tones;

Once I have alignment temporally (overlapping first cycles of sine wave) and magnitude wise, I can play with the sub gain setting if the actual listening test prove excessive bass or what have you. I think the sub/speakers must align time wise for max potential, at least this is what I have read and it makes sense, on paper;

I was going to place a mic directly in front of the sub 3 inches away; same for the speaker woofers mic;
Cue up some bass tracks or just a sine test tone, trigger the scope on one mic and see how they line up. I am 100% positive if I run the sub off the amp output; the acoustic rising wavefront (the first cycle) will arrive at least 10 ms after the rising slope on the woofer output, due to the delays in the sub;

I will repeat the test at the listening chair to see how the alignement changed after wave fronts traveled 9 feet;

Once the entire room "pressurizes" does this time alignment still matter that much? -- we don’t listen to successive impulse trains...we listen to music in a complex environment with lots of interference patterns;

I can, in theory adjust the JL phase to exactly overlap the sine waves but the sub woofer will always lag the speaker woofer by a whole cycle. This may mean absolutely nothing  sonically, or it may be perceived as muddy or too fat.

It’s going to be a fun few weeks figuring all this stuff out!

If I end up hating the subs / can’t get them to gel, I guess I can toss them in our home theater or sell them;

In my previous post seconds should be milliseconds.