White noise from new Stereo
 

I just got done installing a Boss BV760B in my 07 Ford Mustang and I'm getting a constant White Noise/Shhh Noise from the highs.

I tried unplugging the antenna, unplugging the RCA Cables, re-reouting the ground from the head unit to the chassis.

I've run out of ideas and just to clarify the noise is 1 constant level (does not get louder or softer as you change the volume). It's overpowering the music though and makes it unlistenable.

Please help me!