Hope you guys won't mind answering a few questions from an audio newbie. First heres my simple set up that i have in my max:
clarion HU
audiobahn 3 way 6.5" front doors
audiobahn 3 way 6x9 rear deck
12" jl 12w0 sealed box
audiobahn 4 channel amp
PPI 1 channel for sub

Now, since the 4 channel has a crossover, should I set all the speakers on full or should I use high pass on the front and full on the deck speakers? I read that the deck speakers should emphasize the lower tones and the fronts the highs in order to maintain proper staging. But since all my speakers are 3 ways will that help?
Second, I read that in order to set gain, you should set gain at the lowest position and turn up HU volume till you get distortion then lower and then do the same thing with gain control. Problem is that it doesn't seem to work with my sub. With the gain set at min, I can turn my HU volume to max and barely hear any bass. Then, I can turn my gain almost to the max position without any distortion. Keep in mind that my amp is only 150 watts at 4ohm i think. Is that the correct way to do it or will I blow my speaker?

Sorry bout the long questions but I'd really appreciate any help.

Thanks

 

Dude, you are partially there.

First, turn the high pass filters for the front at 100-120 and the deck to 60-100.

Then, turn head unit and amp gain (for sub) all the way down. Turn head unit as loud as you ever think that you will play it. Next turn gain on amp up until you hear distortion. Lower it until the distortion is gone and you have the optimal set-up. The most sound without damage to your stuff.