I swapped out a water-damaged amp from a '73 Mercury Cougar and wired four speakers (2 frnt Door/2 rear door panel) as shown here, but did not end up installing the Sub-woofer. The way the speakers are shown gives Balance but no FADER response. Should the speaker all now be separated into their own channel? Can someone please post a best wiring solution? CustomAutosound USA-230 Head Unit, Cerwin-Vega Mobile H7653 HED Series 3-Way Coaxial Speakers (6.5", 340 Watts max); TS400X4 Taramps Amp.