Wind noise only in dry weather

Hello together, I am new here and have bought me a Phaeton 3D, year 12/2008 with 80400km. I know, there are already topics to this, but they help me unfortunately not further. During the test drive it rained and I heard no wind noise, only divine calm (except for the light rain) compared to other vehicles. This is unfortunately different in dry weather, from about 100km it whistles unpleasantly from the front right. After I have already pasted all the column (incl. sliding roof un d door handle) and also inside in all possible places by a passenger with a towel covered the cracks and openings and no improvement occurs, I have the suspicion that these wind / whistle noises from the air ducts in the vehicle sound or are generated there. Can that be, what do you mean? Greetings from Bavaria