I will once again link to xoxos VST plugins (my fanboyism is showing): http://www.xoxos.net/vst/vst.html#models http://www.xoxos.net/vst/vst.html#models Scrol

I will once again link to xoxos VST plugins (my fanboyism is showing): http://www.xoxos.net/vst/vst.html#models http://www.xoxos.net/vst/vst.html#models Scroll down to the "virtual machine" plugin. It's closed source but there is a PDF that explains how it works, with a nice signal flow graph. You can also get a very good idea of the underlying algorithm by playing around with the parameters. Also, since someone else is asking about generating squeaking tire sounds, xoxos also has a "friction" VST that does this. There's no audio demo so I made a quick one that emulates tire squeaking: http://007ee821dfb24ea1133d-f5304285da51469c5fdbbb05c1bdfa60.r16.cf2.rackcdn.com/friction%20tire%20squeak.mp3 http://007ee821dfb24ea1133d-f5304285da51469c5fdbbb05c1bdfa60... Edit: and while I'm at it, here's another engine sound demo using "virtual machine" (less interesting than the one on his website, but I put a bit of reverb/ambience on it to make it more realistic): http://007ee821dfb24ea1133d-f5304285da51469c5fdbbb05c1bdfa60.r16.cf2.rackcdn.com/VM%20rev%20up.mp3 http://007ee821dfb24ea1133d-f5304285da51469c5fdbbb05c1bdfa60...