Sunroof

[simes69]

Having the sunroof open on my 996 causes turbulence and noise in the cabin - a very loud and rapid thudding caused for the same reason as you get a noise when you blow across the top of a bottle I suppose.
If I open the windows a crack it solves it, but I wondered whether there is (or is suppoed to be) a deflector to break up the air flow on the front edge of the sunroof.

[fidgits]

this is simply an effect of airflow over an opening into a sealed area...

as you say, best way to avoid is open the window ever so slightly, or drive at a different speed.

[lagerlout]

Strange, I don't really get this in my 996, well not loud, just slight.

You want to try an Audi A2, what a mare that car is, can't even have the window open as it thrums like you wouldn't believe.

[luke1963]

same on mine too, if you press the sun roof button again it will retract it another inch or so which will get rid of the 'booming' sensation. I find that it only happens on mine at certain speeds but is kind of annoying, it sounds like a louder version of tyre noise except you can feel the pressure on your ears

[Murray993]

happens on loads of cars. I just open the windows a litte as already suggested or push up the deflector a little in the sunroof (not sure if there is one on the 996).