Deciding between two potentials setups:

1) 2 amps: One 4-channel running front components and rear coaxials, and one 2 channel bridged pushing my single 12".

2) 1 amp: One 4-channel running front components with 2 channels and other two channels bridged pushing 12". Rear coaxials would run off head unit power (pioneer FH-P5000).

If I went with option 2, can I double the power to the rear coaxials by bridging the head unit? Is that possible?

 

No it is not.

 

You may find that head unit power is sufficient for the coaxs. I did

 

Headunit is 50X4. If I'm running a 75 watts or so per channel to the components via the 4-channel, think I'll have a good balance between front and back?

 

Your using 2 channels of the amp for the components and bridging the others to a sub right? IMO that would be best, and use head unit power for the rears..or at least try it out and see if it suits your taste. HU power is 50W max most likely and only 15W or so RMS..still enough IMO because it is so close to your head and you want your quality mid-high signal coming from in front of you not behind..

 

Yeah, 2 channels to the components and 2 bridged for the sub. I already have a 2 channel pushing the sub, so the decision is to replace it with a 4-channel or add the 4 channel and have it run fronts and backs, keeping the 2 channel on the sub.

So only real advantage of going 4-channel only is simplicity and weight savings of only one amp, since I already have the 2-channel. Maybe drain on the battery. Question is, do these benefits outweigh the loss of power to the rears.

Sounds like you would say yes, dannichols. Thanks for your help!

Any other opinions on the matter?

 

If you're worried about weight consider each amp. You can find some moderate power 2 channell and Mono amps that are pretty light weight. My suggestion would be 2 amps, one for the components, one for the Subs, and run the rear 6.5's from head unit power. As a third option you could pick a component set that allows for RAF speakers. Diamond Audio Hex for instance, has a third hookup on their crossover that sends full audio to a set of rear speakers at about 20% power..

 

Or he could choose an amp that has passive outs for additional channels. My xtant x603 (3 channel) has 2 additional passive outs for running other speakers at an attenuated level.

 

Get a five channel amp.

 

Aren't the passive outs low level RCAs meant to be run to an additional amp? How would those hook into rear speakers? The RAF outs from the XOVER are attenuated by 80%