BMW 550i - soft whistle sound ??

Hey Guys,
I just got a 550. At slow speeds, as I accelerate slowly, I can hear what I describe as a soft whistle sound. I cannot figure out what the heck it is. Has anyone experienced this? Please give me your input, I am frustrated. It is one of those things that I know if I take it to my dealership, they will tell me they cannot duplicate the problem. It does not happen all the time.

I read it here that the door cabin may need some adjustment because of this a cabin noise well known issue in z F10 model I assume ! GLTU

Hi,

My 550xi has the same high pitched noise you describe. It seems to happen when the accelerator is being pushed. For me it dissipates when the foot is off the pedal and cruising. I'm guessing it has something to do with fuel injection. IDK though.

Is it coming from the window? There is a known seal issue on all 5 series models.

I usually drive with the fan on but AC off and have noticed the soft whistle coming through the air vents in the middle. When I turn the fan off though the the whistle goes away. I have a scheduled appt for friday to bring my car in and plan to let my SA know about it. I'll let you guys know if it gets fixed after the service appt.