PhoS

I am victorious! I got a pair of isolators but only ended up using one of them. With both isolators on my 4ch amp's f/r channels the noise was louder! The sub doesn't transmit make any noise so I left it alone.

I think crap RCA's are at fault here. I could tell from when I was moving the wires around. Should have stuck with the usual brand I thought i'd try somthing new ugh...

The metra boxes are definaltly some cheap crap as well. I'm not at all impressed with the build quality.

Finally no hissing , it was seriously making my blood pressure go up..

Lee3333

I know exactly what you mean, both about the hissing and about the Metra boxes. Lots of money for it, also. They make 2-one if you use the factory amp, which I bought first. It created so much noise that I had to keep the gain down, resulting in very low sound output. Worse, it is not usable if you decide to go with an aftermarket amp. I called Metra tech support, and they acknowledged that the wiring on the HHR creates noise and there is no solution for it. Wish I had known that before I tried using the factory amp. You need to shell out another hundred plus dollars for a different model. When I got it, I discovered that it needs to be modified. If you want to hear your turn signal, you need to buy a relay. And if you want to hear your OnStar and mobile phone, you need to buy an additional speaker just for that.

By the way, my first Metra blew up when I tried connecting it to the PAC controls for my steering wheel.

PhoS

The first box I had did not work at all (DOA). I have aftermarket amps/deck , I gutted the pioneer stuff (read crap). My new deck does bluetooth for my phone.

Everything is cool now , I was driving to work this morning wondering if something was wrong because I couldn't hear any hissing/buzzing I had some reception issues before but I haven't tested to see if its still there. I never listen to the radio anyway I have a 160gb hard drive hooked up to my deck with mp3s.

HHR was def. a pain to get setup more so then most cars I hate all this integrated crap...

Now that it's finally finished i'll post up some pics in the sticky thread.

JamesS

Old school installer trick:

The noise is caused by differing resistance on the ground points to various electronic devices. If you get rid of the resistance variations you get rid of the noise. You can normalize the resistance by running a wire between all the ground points.

Simply put run a wire connecting your radio ground point, your line out ground point, and your amplifier ground point. If you still have noise strip the outer layer of your antenna wire and attach the wire to it as well. If you really want to be sure you can run the wire all the way to the battery - terminal.

Good Luck