Thanks, so I was doing it right on the part where I turn the subwoofer level all the way up from the head unit. I had it maxed out at +15. Since I wasn't able to get a signal directly off the head unit RCA, I tuned my headunit through my amp. Gain all the way down, crossover all the way up, subsonic filter all the way down. I distorted at 32/35 with Track 1, 40Hz -0dB.
Now I shall crank my gain at volume 31 at head unit until the distortion lights up as well right? Thanks for all the info btw!