Noise on audio system on 2010 Subaru Legacy

I've had my Subaru for a year with no problems and all of a sudden this week I now have severe, oscillating noise/interference on my audio system that is directly tied to how fast I am going. When I go slow, the interference wipes out the audio - when I'm going faster the oscillation is so fast that I can still hear. When I stop, it goes away completely. It doesn't start immediately when I turn the car on - it takes a while so i'm wondering if something is overheating (electronics) causing this?

Asked by for the 2010 Subaru Legacy
Sounds like some sort of a ground loss in the engine compartment. See your local Subaru dealership for help, as you should still be under warranty.
As it's continued, it is actually something overheating. In the mornings when it's cooler it doesn't usually happen, but the warmer it has gotten, the faster it happens and the worse it gets.

Today it was in the 80s and the sound stopped altogether. I'm thinking that the amp driving all of my audio has some sort of overheating/ground issue because the rest of the console works fine (GPS and such, but all audio (radio, CD, MP3, and Blue Tooth) all have issues.