Setup Question
 

I am just about ready to do the install on my 61 Panel trucks stereo.

I have a pair of Polk Audio 6x9s for the back and a pair of Polk audio 6.5s for the front. I have a 2 channel Orion amp for one of these sets. Should I run it on the fronts or the rears? Whatever set doesn't get run off the amp will be run off the head unit. I also have another amp for a couple subs.

Re: Setup Question
 

Use the 2channel to power the front 6.5's They are your primary stage, and will carry most of the responsibility in terms of sound reproduction. A good amp'd power source will allow them to work to their potential in terms of volume and clarity while avoiding clipping/noise.

The rear 6x9's are for bass and rear fill. You won't really hear them "over" the front speakers, just in addition. They won't be as clear at high volumes as the front set, but 6x9's in general aren't the clearest speakers, whether or not they are amp'd. If your HU has 3 outputs, you can always come back and add the 3rd amp for the rear speakers later with ease.
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If for some reason the 2channel is overpowered, you could consider running them paired as just L and R (no front or rear control)..but you would need to check the resistances and output on the amp to see if this is pheasable. Its more common on older setups that had 2 speaker control only, but it can be made to work.

Its also possible to wire the rear 6x9's off the sub-amp, but you'd have to keep the sub output set as "rear" or "rear/sub" instead of just "sub".