It is probably the car's original design defect - aerodynamic problem perhaps. Please share if there is a solution.

Loud buffeting wind noise with either rear window rolled down or even just open a little. So loud it will vibrate whole vehicle as well as being so loud you can't hear anything else. Noise will go away if one of the front windows is open or partially open. Noise diminishes more the farther the front window is lowered. Very annoying and obviously a manufacturing oversight or defect. Not sure if a fix can be done. Seems like a design flaw.