question about head unit settings (Alpine)

I just installed a bluetooth adapter for my Alpine CDA-9886M head unit. As I was messing with the head unit settings to get the adapter to work, I discovered a bunch of other settings I've never really adjusted. My unit has a subwoofer setting, which can be set from 0 to 15. It was on zero, which I guess is the factory setting. When I started to turn it up, my subs started to come alive. I've never really felt like they were as strong as they should be, and maybe this is the reason why. From some research I've done, I now believe that the subwoofer setting (which is different from the bass setting) controls volts to the amp, and should be set at 15 to provide full voltage to the sub channels. So, I think I'm supposed to set it to 15, then readjust the gains on my sub amps, presumably turning them down a bit. Does this sound right? I just wanted to run it by everyone before I start messing around with my gains. And, I'm printing out my head unit's user's manual to go through all the other settings. Unfortunately, it doesn't seem to address this issue.

Adjustments to your amplifier's gain setting should be made with all settings on the head unit set to "0" or flat. Don't forget to turn off the loudness setting on the head unit as well.

Originally Posted by 99ProAir

Adjustments to your amplifier's gain setting should be made with all settings on the head unit set to "0" or flat. Don't forget to turn off the loudness setting on the head unit as well.

That's the way I did it originally, because that's what the directions for my distortion detector recommended. But, a bunch of dudes on the car stereo forums (in threads I've looked at, not started) say that the subwoofer setting on an Alpine headunit controls preout voltage, so in order to get the max preout voltage it should be set to 15, and then the gains should be set.

I went ahead and set the subwoofer level to 15 and then readjusted my gains with the DD1 and it made a HUGE difference. Probably doubled the output. I can't believe I've been tapping into about half of my subs' capability for the last two years. So, for all those with an Alpine headunit, check your settings!