Here'* the low down. There'* one channel of wiring going into the door for cars with the factory components. The 5.25"'ers hook up directly to that.
It was my tweeters, the actual speakers I blew, not he crossover. I tested that because I wanted to give my brother the tweeters, but they were history.
The rear 6x9'* have two sets of wires. One is for one coil (mids and whatnot) and the other is for the 2nd coil, the "bass" from the "amp" that delco made for GM. I forget which is which. In fact, I just guessed and checked with my car when I installed.
Okay, the "gain" slider deal, that'* a variable resistor. Properly wired, between the output of the HU and the amp inputs, it works. It can't damage a thing if connected properly (as in, dont' hook up the illumination wires that make it glow orange/red to your amp or some dumb thing like that!). However, it might not give you the results you expected.
Scenarios: A) it works perfect, which won't happen. B) the output is always lower than you'd expect, C) the relationship between slider position and sub volume is NOT linear (it all of the sudden gives tons of bass with little movement, and vice versa) and then there'* D) a combination of B and C that most will experience.
Give it a shot, if you like the results, super! Otherwise, if enough people bug me, I'll desing a simple circuit that will convert the slider into a useful tool for most subs. But not until January...finals are coming up!
'95 SSEi, few electronic mods (and a stupid coupler)
HU (Sony MDX-CA680, European Ver; Sony 4x3-ways; 91, 93dB)
Yup, that'* ISU