I installed my rear speakers and had them going just by themselves, brand-new Kenwoods so they were good quality, but they crackled a bit. Then I installed my fronts, sub and amp. And now every now and then I'll hear a pop coming from the rear's, then all sound will cut out for about thirty seconds.

I'll need to check the wiring and everything, but can someone narrow it down a bit for me, where to check. I don't want to have to check the wiring for the sub and amp, the fronts and the rears all on both ends.

i take it you are running the speakers off the factory wiring... are you running an aftermarket unit??? the crackling sounds like a dodgy joint which could be shorting which causes the pop, a short will shut down the speaker out puts of your unit as a fail safe this however will only work for so long before the output shits the bed... so check the speaker connections use appropriate female blade terminals on the speakers and make sure joints are properly insulated.

What amp and what sub? How much power (RMS not peak) are you running into the sub?

Are you amping the speakers aswell? Are you using factory wiring?

Have you tried grounding to a different location?

And lastly how is the gain on the amp set?