What are we talking, crossovers, gain settings, mono block's, or multi channels, you need to be more specific with your question.
turn amp gains to nill , deck volume 3/4 bass and trble flat . gradually bring up gains and adjust hi or lo pass filters as required untill you achieve best sound. if 4 ch or multiple amps set 1 amp or channel at a time. if running subs then turn hi pass filter on for front and back but dont set too high a freq . adjust to your own taste. don't push gains higher than 4/5 or h/u above 80% as you will get system distortion.