Noise in front right speakers only...

[Spooner]

Ever since I bought my Vibe about 8 months ago it has had a humming noise in the front right speakers. I messed with it a little when I first bought the car but now it's getting really annoying so I want to try to figure this out. It's not your traditional alternator noise, its just a low humming but will change slightly when I shift from park to drive or whatever. I do have an aftermarket head unit that I installed that I have used in several other vehicles and it was working perfectly before I installed it in the vibe and I have pulled it out and checked all the connections and all that looks fine. Also it was doing this with the stock head unit when I bought the car. I have pulled the door panel off and checked out all the wiring and everything looks good and clean and moving the harnesses around doesn't help. I also checked out the amp and the harnesses there and the harnesses in the passenger side kick panel and everything looks perfect. I can't figure it out but I was hoping that someone has maybe had this problem before and can lead me in the right direction. Sorry about the long, boring post

Oh and mine has the moon and tunes package.