In Reply to: yes(more) posted by DrBimmer#2 on October 24, 1999 at 01:17:19:
: Yes..I have experienced this in my '00 328Ci and my parents '99 Nissan Maxima. It also happens in my friends car. It's just the way the aerodynamics of cars these days are made. Hope that helps.
Ever blown across the top of a soda bottle, or played a Woodwind instrument. Same basic effect. The air is pressurized and then rebounds into rarifification. The frequency is defined by the cubic volume of the pressurized space. When I get a chance I may measure the frequency, and then see if a simple helmholtz resonator could be built in the trunk to cancel the energy and alleviate the noise. If anybody else out there has an engineering bent, see F. Alton Everest, Master Handbook of Acoustics.