Are all the main speakers running off the amp and none from the deck itself? Front fade should quiet the mains and rear fade should quiet the subs due to that you have two full pairs of RCA that you ran. When I said the fade would not work, it was for the fade control of front main speakers from the rear main speakers only. As for the volume level and the amp shut down. The gain control on the amp may be way up. Most amps to keep from distortion....the gains need set down to maybe 1/4. How do you have the subs wired? + from ch3 to + on 1 sub...that subs - to + on other sub...that sub - to - of ch4 amp? IF you have quick connects on the sub box for each sub...this can be done quickly from the box connects.