Sounds like the sunroof-open-all-the-way-with-windows-closed noise.
You know, I noticed that with a '01 325iT I have as a loaner while the dealer readies my 530i. But I've never had that effect with my 323i.Kaz said:Sounds like the sunroof-open-all-the-way-with-windows-closed noise.
Its a resonance... most cars I've had have this. Some combination of interior volume and roadspeed will create this. Just like a wind instrument, why it makes the noise.Cliff330i said:Guys, yesterday I was driving and I lowered the right back window all the way. As soon as I lowered, this weird acoustic booming sound could be heard. When I say, weird, I mean WEIRD! I was like a bass drum beating very fast perfectly in time. But, it was so loud and deep that it hurt my ears. I mean, it was overwhelming that I just couldn't stand it. It's hard to explain but it was very overwhelming and forceful. I lowerd the other back window and it go even worse! If I have all windows down, it doesn't do it nor if I have any combination of front windows adjusted. It was like something out of a moive sound effect. Maybe some one has experienced this? I don't know what the hell it is. If you have ever been outside and had the wind slap you right in the ear; that's exactly what it like but in a rhythmic fashion. Cheers, -C
Welcome to the wonderful world of acoustical physics.Cliff330i said:Guys, yesterday I was driving and I lowered the right back window all the way. As soon as I lowered, this weird acoustic booming sound could be heard. When I say, weird, I mean WEIRD! I was like a bass drum beating very fast perfectly in time. But, it was so loud and deep that it hurt my ears. I mean, it was overwhelming that I just couldn't stand it. It's hard to explain but it was very overwhelming and forceful. I lowerd the other back window and it go even worse! If I have all windows down, it doesn't do it nor if I have any combination of front windows adjusted. It was like something out of a moive sound effect. Maybe some one has experienced this? I don't know what the hell it is. If you have ever been outside and had the wind slap you right in the ear; that's exactly what it like but in a rhythmic fashion. Cheers, -C