Car headunit / amp / speakers question

[andy-xr]

Want to replace the speakers in my car, has 2 x 10cm and 2 x 6x9's that I've got replacements for.

I want to add an amp to drive the speakers and also add a sub for a little extra bass. I've found some decently priced speakers that'll replace whatever's in there now, and won a small sub that came with a 2 channel amp on eBay.

I've also bought a 4 channel amp that has outs for l/r front and l/r rear

What I'm thinking of doing is running new wire to each speaker back to the 4 channel amp, then running the leads to the head unit and wiring up to the battery etc

For the sub, I'm a bit unsure what to do - I've got a separate amp for that and I'm fine with electrifying it, but I dont have any additional outs on the back of the head unit

I could upgrade the head unit to 2 x RCA outs, would that be a better option than trying to do anything wiring related?

[lufbramatt]

Would have thought your 4-channel amp will have a pre-out for the subwoofer amp. This means you can set the crossover frequency between the sub and the midrange drivers via the 4 channel amp.

[andy-xr]

Thanks for that, just coming back to it after actually buying the amp now with a false start slowing me down

I've got a 4 channel amp, it has specific speaker wiring for FL/FR/RL/RR speakers. I've got a head unit with 2 x RCA outs.

If I wanted to get sound coming through all the speakers would I be OK with just one set of RCAs going from the head unit to the amp? It doesnt appear to give only front or only rear as an option on the head unit, and I'm guessing the amp will push out whatever comes througb it to all speakers?

Or am I missing something?