help weird noise coming from center vents

Hi, I have '01.5 A4 2.8 with Bose and 53K miles and I am starting to hear this noise coming from the center vents when I turn on the AC. It all started
happening after Isabell hit the East coast last week. The noise gets louder when I turn up the fan speed, and dies down when I bring it down. I only hear it when the inside temperature is higher than what the climate control is set at. The noise is kinda like when you put like a twig or something in a pedestal fan or something like that..
Please any help would be appreciated..
Long live the Quattro!!!

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