Can someone help me identify this noise?

It only happens after driving for a bit, and then remains until the car is turned off and then restarted, at which point the sound stops.

Here is a clip of the sound. It seems to be coming from the serpentine belt area.I used a stethoscope but wasn't able to really pin point it.

https://www.youtube.com/watch?v=iOeA...ature=youtu.be

 

Sounds like a bad accessory or tensioner bearing to me.