Tonight I wrapped up the box build and did my initial installation. Everything plugged up as expected. I had a little trouble with my remote-on relay activating with the override switch (so I can turn everything on for testing without a headunit), but I finally remembered the relay's ground gets offloaded to the headunit end of things, so I had to ground one wire up front and it started working.
The initial powerup was a little tense because I always hate putting in big fuses like the 80A fuses I had for each amp. It takes a lot to blow a 80A fuse, so when they go it makes you jump at minimum. I did one more check with my ohm meter to make sure everything downstream was effectively open and not shorted to ground, then popped the fuses in without any drama.
With the power applied + my remote on relay activated, I was a little surprised there were zero indicators on any of my equipment showing it was powered up. I figured I'd made a mistake but after verifying my bluetooth adapter was discoverable and the DSP at least had 12v at its power connector I decided to try and connect to the DSP over USB.
The connection was a success and after a quick route configuration I was ready to pipe in some music over bluetooth with my amp crossovers roughly set + all my gain turned way down.
I was overjoyed with the sound of music as soon as I started playing it on my phone. Admittedly, at this stage what I was dealing with was just a big, expensive, untuned bluetooth speaker, but it sounded pretty great to me!
The only problem I found last night is that it appears my front passenger tweeter wasn't working. I'd actually spotted this problem a couple of years ago when I initially verified all my in-trunk speaker wiring. I even ordered a replacement tweeter and broke the door down to install it, but found the tweeter unplugged. I can't for the life of me remember if I went ahead and replaced it or if I just plugged up the old one. Either way, it still appears dead, so I'm in for another door explorative surgery at minimum :(
The tweeter debugging might hold me up a bit, but as soon as I resolve that problem I'll disable the amp crossovers and start tuning my DSP's crossovers, gains, time alignment, and finally my EQ with REW + my UMIK-1 calibration microphone.