07 acura tl humming noise from speakers

Installed an amp and sub to a 2007 Acura TL with stock deck.Used the speaker inputs in the amplifier and when the car is started,alternator noise is heard from speakers. Has anyone experienced this on a vehicle like this which has a premium sound system. Thanks

The noise is coming from the sub you added, or from the OEM speakers?

The noise is coming of the speakers.

there could be a number of issues happening.  what kind of amp is it?  where and how is it grounded?  what i would suggest is checking your ground point to start with.  make sure the wire is of adequate guage and attached firmly to the vehicle chasis.  try to stay away from grounding to metal plates that are only spot welded to the frame.  also make sure you have scraped away the paint from the vehicle surface to where you are grounding.  if the noise is still persistent then i would try a line level adaptor.  this will convert your speaker levels that your using for an input down to an rca level.

Iam sorry it is not the car speakers but the aftermarket subs that make a weird loud exhaust type noise when the rpm is between idle and 2000 rpm.I will try a hi/low adjustable converter to see if there is any difference.By the way the amp/subs are a cheap xxx brand which the customer supplied.