[BIGglaSS]

Tuning a system will vary from person to person and the acoustics of the install. This is generic, but will get you close. There are a few different ways to do this, because you have crossover control via the head unit, the amp, and the JL C5 crossovers. To keep it simple, this is how I would do it. In the end, you can tweak it to your taste.

Set channel mode switch to 4ch

Sub:
Unplug the front/rear RCAs. Plug one of the sub feed blue lines from the head unit (HU) into input sub 1. Set source switch to EXT. Start with level turned all the way down. Set subsonic about half way. This is more important if you have a ported box. But sealed box should be OK. Next switch set to LPF. Set LPF knob to about 2:00 position. Now go into HU settings and turn on SUB. Set SUB volume at 12. Set subwoofer Crossover frequency to SUB 120H. You should not need a higher setting from the sub. After you get it all installed, you can tweak the xover knob on the amp a little bit lower if the sub sounds too high pitch. Now play some music. Turn up the HU volume to about 3/4, and the remote bass knob to full. If the bass is loud enough, all is good. Otherwise, (on the amp) turn up the level knob until it is loud enough or the speaker distorts, then back it off slightly.

Next, rear speakers:
Unplug the sub and front RCAs, plug in the rear RCAs. Amp panel, lower row, left. Set switch to HPF. Set HPF knob to about 1:00. Level all the way down. Play music, HU at 3/4 volume. Turn up level until the rears are loud enough or start to distort. Then back off slightly.

Front speakers:
Unplug rear speakers and sub RCAs. Plug in the front RCAs. Since the C5 fronts have their own crossover network, no need to control it from the amp. You can set this switch to FULL. Turn level knob full down, and repeat for the fronts.

After the levels are set, plug in all the sources and play! After that, you can adjust tonally via the head unit (classic, pop, rock, bass, middle, treble). If you want to tweak the crossover slightly, you can turn the sub LPF down. Anywhere between 90-120 hz is fine. For the fronts, since the supplied C5 crossover has control, all you will be able to do is move the crossover point up. To do that, switch the front channels on the amp to HPF and adjust the frequency knob to what sounds good. Another option is change the jumper pins inside the JL C5 crossovers.

Hope this makes sense.