Stereo noise help

[Sampson]

Hi I just had alpine dlc177r's with dynamat put in the doors running of the factory head unit and I am getting a really high pitched noise notice it with low volume. Any help with what is causing it would be great its making my ears ring

[r-r-redEuro]

it could be your speakers set on high with high treble ? try lowering it.
and are you amplifying your speakers?

[Sampson]

no amp just off the head unit

[traumatized]

check the connections to ensure nothing is lose, might also be a grounding issue.

[tron07]

usually its poor grounding if running the speakers of the HU

[Kodak]

Does the pitch change with engine rpm? Do you still get it with the engine off?