Light grinding noise

02 Outback Sport (Impreza), 75k, auto. Getting a light grinding noise periodically. Sounds like it’s coming from down below. No specific place though.

When?

Cold? Hot? Both?
Idling? In Park? Driving? Braking? Accelerating? Coasting? Turning? Revving?
Can you influence it? Can you make it start, stop, get louder, quieter?
Can you hear it outside car? Only inside?
Please describe periodically.

Cold? Hot? Both?:::: BOTH
Idling? In Park? Driving? Braking? Accelerating? Coasting? Turning? Revving?:::: DRIVING, ACCELERATING, TURNING AND NOT TURNING
Can you influence it? Can you make it start, stop, get louder, quieter?:::: NO
Can you hear it outside car? Only inside? ::: ONLY HAPPENS WHEN DRIVING SO NOT SURE
Please describe periodically.

Have your brakes checked. I’ll bet your grindng the rotor with a worn out pad.

Keep an open ear, this is a Subaru.

The noise may also be from a transfer case/differential or wheel bearing.