We've owned our 2006 Hummer since it was brand new. I keep it spotless it's our pride and joy and have done lots of maintenance through the years to keep it in tip top shape. A few years ago I noticed a audible buzzing noise from the passenger side rear door speaker, naturally I read online these speakers often need replaced. So I replaced them was a nice high quality aftermarket speaker. The buzzing noise went away for about 2 weeks and then returned again only to the passenger side rear door speaker. Thus sent me out on a firing of the parts Cannon, I replaced the front speakers and the tweeters and the head unit and I even replaced the subwoofer. Still to this day the passenger side rear door speaker has a very annoying buzzing sound that comes and goes. Some days it's not so bad other days it's very annoying. I've even traced back the wiring as far as I'm willing to take it and I don't see any wiring issues. Tried adding extra grounds and even making sure any accessories we have plugged in are unplugged and even disconnected the onstar. Do the monsoon apps ever take a dump? Our vehicle has always been garage kept since it was new. It's never gotten wet on the inside and I even made sure and disconnected and clean the pins and I didn't see any corrosion or issues. Anybody have any smoking guns that they're aware of? Thanks again

 

Use oscilloscope to check for random spurious signals on both rear door speakers. Compare signal from each.

 

Suggest removing speaker wires from cone when testing. The test with cone attached.

 

If it is not vibration from improper installation, then you may have the speaker wire being compromised by rubbing on something and making a short/ground?

 

I just solved a similar issue. It was a wire in the signal path from head unit to amp. I did everything backwards also. I was convinced for a long time the problem had to be in the boot going to the driver door. Anyhow you can use a sine wave app on your phone to send out a signal and backprobe with a $10 kit like I did. My journey is documented in the link. It's an H2 but this works for any vehicle. https://www.hummerforums.com/forum/h...09/#post414273