2006 RL with approximately 240,000 miles that consistently makes the attached sound above 25 MPH. Pitch of sound changes with vehicle speed and not engine RPM. Any help identifying source would be appreciated. Thank you.

 

Sounds like the typical high pitched whine documented here with no real fix, along with some loud tires and/or exhaust.

 

Solved. Sound was from a failed driver side rear wheel bearing.