4 speakers + 1 sub 1 AMP, options?

[CoolBreeze]

Hello,
I'm a bit of an audio noob so thought I had better ask for opinions.
I've just completed a reinstall of my sound system. Completely rewired everything from amp to speakers as the previous 'professional' install was pretty horrible (completely stuffed up front / rear / left right connections when they soldered the new speaker wire from amp straight into factory radio harness), it sounded terrible
My set up is a bit mismatched:

Head Unit - Pioneer X8750BT
Front - Alpine SPR60C splits
Rear - Pioneer TS-D1602R
Amp - Some Sony Xplod 4ch 600W from Japan (old) - IN THE BOOT

Wiring as of today:
RCAs from head unit to 4Ch Amp in boot which then runs new cable directly to each speaker. 2 short wires for rears and 2 long to the front.

My question:
I would like to add a nice little sub to the system in the near future but I am currently using all channels of the amp. I hear people traditionally run the front splits off the amp, rears off the head unit and bridge the remaining channels for the sub.
I would like to avoid running new wire from the head unit to the rears if at all possible.
Can I run 2 amps from the set of RCAs somehow? keeping the Xplod for speakers and run an additional Monoblock for the sub?
or would it be better to upgrade to a 5ch or 6ch amp?
What would people do?

 

[rockerpeller]

What your after are rca "Y" splitters. Splits a single rca into 2 rcas. That would let you run a monoblock preferably with a controller to turn it down when you don't want it so bassy (sp?).

I've always run front and rears amped, with a monoblock for the sub.

 

[steveP]

Just run the rear speakers off the head unit and bridge the 2 channels for the sub. You say you don't want to rewire the rear speakers, but it's way less work than your other options.

 

[CoolBreeze]

Thanks for the replies.
I'm going to have to run another RCA for the head unit sub output anyway, bit of an oversight on my behalf unfortunately.
Looks as though I currently have a 10 or at best 8 gauge power lead feeding the original amp. Either a new 5 ch or additional monoblock will necessitate a new power lead.

I'm going to have to run a sub RCA anyway. Looks like it's all coming apart again.

 

[aiwasaki]

A few years ago (like over 10) I had a 4 channel amp that I'm pretty sure I had 4 speakers running in parallel from 2 channels and then the other 2 channels bridged for the sub.

Not sure your (as you put it) old amp will be able to handle this setup, but assuming it will, this would require the least amount of rewiring.

What you should do though is change the connection of the RCA (at the HU) from channel 3/4 to sub. Assuming its a single sub RCA coming out of the HU get a single male to double female Y connector, to connect this to the existing RCA.

If your amp won't handle this then I would suggest you get a 5 channel amp. IMO (unless you want the system really loud/powerful) a 5 channel is a fair amount less complicated and takes less space so easier to install etc.

I think I bought my 700 watt RMS amp for about $300 (off Gumtree) and has more than enough power for my taste. The other advantage of going with a 5 channel is you could reuse all the wiring you have. You wouldn't even need to run an additional RCA if you were happy to have front and back left channels running off the same channel at the HU (same goes for front and back right channel), with just a Y splitter going into the amp. This would mean though you would have no fader control (from the HU) for the mid/high channels.

I've got photos of my stereo install on my members page. It doesn't show a lot of the actually wiring setup, but it does show where I mounted.