Audio Systems: Buzzing sound through speakers, infinity sound, fuse box

Question
QUESTION: I recently replaced my battery in my 1998 Dodge Intrepid,
immediately after that I got a buzzing sound coming through
my speakers. I checked the ground, the alternator and starter
and their all good. Do you think it could be the new battery
I just put in ?

ANSWER: that happens only when the engine is on?
try to turn on the ignition and listen to the radio   
it is posible that come from the battery

---------- FOLLOW-UP ----------

QUESTION: The buzzing sound is there wether the engine is on or off.
Since my first question, I did change out the battery and proved it is not the battery.  I have also changed out the
radio and speakers and found no change in buzzing sound.
I did hear some extra sounds under the hood in the fuse box,
thinking it could be one of the relays, pulled out one at a time and still no change.

this has become quite a challenge.

any other ideas would be appreciated

thanks again

John Kravec

Answer
you have the infinity sound system with 10 or 8 speakers look at the logo on the driver door  the problem can be the amplifier turn on relay it is  on the right side of the radio left side of glove box
or the amplifier got damage when you replace the battery