So my headunit Pioneer DEH-3200UB only has 2 sets but I plan on using a 4 ch and a mono block amp and need to know is there a way I can expand it to my needs.

Two sets should be enough for two amps. Depending on the 4 channel there could be an option on the amp to use the input from "A" for both "A" and "B" channels or you can get a splitter to use.

Depending on the amp, the 4 channel may also have a line out on it to run to another amplifier.

What amps are you running?

Kicker 350.4

Kicker 300.1 or 400.1

Kicker 350.4

Kicker 300.1 or 400.1

Where are you in Louisiana?

Best option would be to do splitters at the amp. You wold lose front/rear fade, but still have Left/Right balance.

Kicker 350.4

Kicker 300.1 or 400.1

Where are you in Louisiana?

Best option would be to do splitters at the amp. You would lose front/rear fade, but still have Left/Right balance.

L/R balance at hu but would still have fade using the gain at the amp. i believe you'll still need the splitters. u can find a cheap pair at walmart IIRC

Bridge the four channel to your fronts only and then you will have enough

Bridge the four channel to your fronts only and then you will have enough

x2

+2..