How to wire single channel to 4 channel
Sorry I have most this figured out already but I'm not a sound system guy at all. I already ran the single channel a few weeks back and then Got a good deal on a 4 channel. I already figured I'd need to split the power, ground, and signal so now problem there. I guess my question is mixing the 4 channel into the current set up for the speakers. Not sure on the rca cable type or getting the speakers hooked to it either. I've attached pictures of what is installed and what I want to add. Thank you so much in advance.
Existing head unit back side
4 channel im wanting to add in
And single channel already powering my sub








