I have a 2006 silverado with a 'os to bose' unit interfaced. Everything works fine, except the rear speakers are muffled, they are way to low.

I even replaced the 'pac os to bose, and that is not the problem. I tried every setting, and double checked all the wiring, I even took it to cc, and had one of there installers listen to it ,and he said it did not sound right.

Doe's anyone have an Idea what could be wrong...Thanks

Do you have any of the "listening environments" turned on (studio, living room, etc.)? I know that when you turn those on it adjust the time delay of the speakers to create the envinment and the rears always sound a lot different from the fronts.

OK, the Bose system in the new GM's......where do I start? First off, before you remove the factory head unit, make sure that you have set all your tone, fader and balance controls to center. The amplifier does all the sound processing, so, even if you pull the head unit, the settings are saved, meaning, if you set the bass full upbefore pull the radio, your new system will be bass-heavy, no matter what.. The amp also fades by filtering out the mid/high frequencies out of the audio signal to simulate a front/rear balance. Unfortunately, the aftermarket interfaces do not do this, so the rear output from the rear of the factory amp gets kinda ---- stuck. I have tried numerous different methods to get around this, and short of bypassing the factory Bose amp (which kills the OnStar, by the way), nothing really worked. Thank you GM, thank you. So, if anyone else has figured this out, I, for one, would love to know.

You sure about that onstar bit. I've ripped out the bose amp in gms before and still had onstar functional.

That helps ,Thank you. Tomorrow I will reinstall the factory radio and reset everything to center and see what happens I will let you know..THANKS

The newer GM's with the BIG radio and a separate Bose amp usually have the OnStar audio as one of the amp's tasks, although you can get a line-level audio out of the OnStar brain, but I've only done this on the H2.

I set all the controls back to center on the oem radio , and it helped a bit, but not much...