I am new to the forum and looking for help. I have upgraded the sound system in my RAM 3500 and am having problems getting the best quality sound from my amp. I am using the head units 4 channel speaker outputs to drive an Audiocontrol LC6i. Using the LC6i's internal channel summing I get 6 preamp outputs 2 front, 2 rear and 2 the summation of front and rear. These 6 preamp outputs drive my 6 channel Nakamichi NKTA75.6 amp. I have 2 powered subwoofers tapped into the LC6i so I can drive 3 sets of 4-way speakers from the Nakamichi. I get a ton of sound from the setup, however there are setting on the amp that most likely are not optimized for the 4-way speakers. Can someone help me with how to set the HPF, LPF, crossovers, etc for the 6 channels? A pic of the input side of the amp is included. Thanks in advance.