Electrical Hum in front speakers

[smokievol]

I am having the dealer check out an electrical hum coming from the front speakers of my Shaker 500.
I had no such problem on my 2006 V6 Shaker 500, but the 2008 GT does.
I noticed on the 2008 GT that there is electrical noise when you turn off the radio. I went and checked a 2008 on the lot and it has that noise also. It is very faint, but it’s there.
Mine is more of a louder hum coming thru the front speakers. The dealer has changed the head unit, noise still there. Changed the AMP, noise still there. Now he is stating that it may be on all Mustangs and if so there is nothing that can be done.
My next question for him is to change out the front speakers.

Does anyone else have this problem?

 

[erzats]

check speaker conections for polarity issues. I seem to remember when hooking up speakers a hum would develop if speaker wires were hooked up wrong. Or a ground perhaps.