I'm lost. For some reason whenever I exceed a certain speed in FS9, (different with each aircraft) The wind sound changes from it's usual "windy" noise to more of a clicking or buzzing. This has only developed since a reinstall with XP 64bit. I really don't think it's hardware, because I've already tested with a different sound card. (The card I swapped for the original was from a different manufacturer, so that should eliminate the possibility of this being a driver issue, too.)

I'm not too worried about it 'cause I'll be formatting and reinstalling soon, but it still bugs me.

Anyone else been through this?

Yeah, it used to do that with me when I had FS9, I always thought it was some kind of warning horn.  :-?

I thought it was related to XP X64, so I tried a test install of X86 with the same problem.

I finally figured it out.

I noticed several things about this problem.
1) When ever the sound would start to buzz, I would get micro-stutters on the screen.
2) I would only hear the buzzing when I was in the cockpit. (2d or virtual, didn't matter)
3) I would only hear the buzz when I was able to see the ground, or the clouds. The more I could see of either, the worse it got.

So, I changed sound cards. No good.
I ran DXdiag.exe. All checked out fine.
I updated drivers. No change.
I updated DirectX. Nothing.
I turnd down my soundcard's hardware acceleration, and noticed that with it all the way off, I didn't get the buzzing anymore, but during the times I would normally hear the buzzing, I got no sound at all.

So since I knew the issue was limited to FS9 only, I booted the sim, and as a last ditch effort, started messing around with my sliders. After a little trial and error, I discovered that it was just because I had my target framerate slider set to unlimited. Set it to 90fps, and it got better. 80fps, better still. 75fps and the issue is no more.

Not sure if this will help anyone else, but after all the frustration and subsequent troubleshooting I ended up doing, I thought I'd post this and hopefully save someone else the headache.

Just one of those things that is so simple, I overlooked it. :-[

A big thank you to you Groundbound1 :D

Was wondering why I had this problem that i never had before !!!

Because  i just bought a new powerful config so i just pushed the fps to unlimited and got this cracking , static sound.

I did all kind of tweeks not to avail....

Since reading your post went down to 90 fps and it works like a charm ! 

BIG THANKS AGAIN !

Wow, old thread! (Forgot all about it) Really happy to hear that it helped though. I knew I couldn't have been the only one. ;)

Cheers! :)

Well this thread is even older now .. but still pure gold!

I too had this problem with a new FS PC (2 in fact) and had spent days trying to fix it. Then I found this post!

Thanks so much, you're a lifesaver. Just goes to show how important it is for users to post up findings and tips.

Thanks again!