strange noise after installing aftermarket radio

[CoyneJ]

i have a 99 a4 2.8 quattro with bose system

after i installed the radio some noise started to come from the rear'
kinda sounds like the supercharger buzzing
at first i thought it was something wrong with the fuel pump but after i turned of the radio it seemed to stop
the strange part comes in that the buzzing is just like the supercharger
the higher the rpm the louder the buzz
any clues what could it be?

this is the radio i have right now
http://www.crutchfield.com/p_130X680...T.html?tp=5684

[naiku]

Typically a bad ground / ground loop is going to cause that exact sound.

[CoyneJ]

so should i find a better ground or what should i do?

[CoyneJ]

pulled the radio out and found of of the ground cables that attaches to the radio body was disconnected, hopeful this fixes it :)

[naiku]

so should i find a better ground or what should i do?

Yep, although...

pulled the radio out and found of of the ground cables that attaches to the radio body was disconnected, hopeful this fixes it :)

Hopefully that fixed it for you :)