yes, sorry I missed the word gauge.

it depends on the crossover you use. normally you would set the rear pre-outs to subwoofer and run the front stage off of the front and the sw off the rear if you only have two pre-outs.

if you need three inputs for the crossover you can use y adapters on the rear channel. if you use an eq it will take your front output and give you three outputs. one for rear, one for front, and one for sub.

 

Well I'm building this system piece by piece so right now i don't have the money for the crossovers or anything really I just want to go step by step and get research done before I do this, by the way thank you for helping me I don't want to have a system composing of a sub and an amp with tons of bass where you can't hear the music and the bass is distorted, all that mess is how people in my town do theirs I want to really do it right.

Anyway, would it be possible to get something that would split my rear pre-out into two pre-outs? Kind of like splitting them then I could plug my front pre-out and one rear pre-out to my compact that pushes my 6.5s and 6x9s then have that extra rear pre-out to my subwoofer amp.

 

y adapters would split the signal. fairly cheap. and some amps have an out on them. I didnt think about that, but if your 4 channel has an out you can run your front to the front and the rear to the rear, and just use the out on the 4 channel amplifier to feed the mono block a signal.

 

That clears that up the out would still be pre-amp right becasue I was told that an amp couldn't be fed a amplified signal as it would be too much for the amp to handle is this true?

 

it is a pre-out on the amp.

an amp can be fed an amplified signal. that is what a line driver is. you just have to set the gains accordingly. now you would not want to run wires from the output on the the amp to the high level inputs on the other amp.

 

four outputs (front and rear/sub) is common on cheaper head units.

the rear/sub is switchable in the head unit to be fading (rear) or non-fading (sub). this allows you to still power rear speakers from the head unit while having front speakers and a sub are powered by an amp. depending on the sub selection and amp selection, you can power front speakers and a sub from one 4 channel amp.

you don't really want to feed-through to the sub amp because you want to keep the sub amp on the rear/sub output on the head unit (especially if the head unit also offers sub level control). you want the ability to adjust levels from the head unit.

using a fused distribution block to feed both amps is common. the amps can share a ground or ground to the chassis separately.