Hey!
I was experimenting with using sound data some and came up with a pretty nice app: http://www.matumeistari.lv/GUST/SpinnySound_JARs.RAR .
It runs using Ess (www.tree-axis.com) and OpenGL.

I worked out that showing FFT workings would be quite a tough one, so here I'm using only the sound input buffer. The buffer is a float-array that takes data from your system's recording engine (the main sound software, you can choose which sound line is the one presented as main input). By default, it should be reacting to the microphone, so you can set it to use the output instead and have a visualisation for your system's sounds and music.

I started by just seeing how it works drawn in a straight line, then tried to curve it into a circle. I tried to get some pixel effects (to make the fading look more interesting) on but it didn't work too well. So I figured to stick with the natural JOGL coolness.

Hmm. I tested it with a few people and they said it works fine. http://www.matumeistari.lv/GUST/SpinnySound.jpg

I understand alot of people here have Macs, right? I'll upload that one too in a sec, then.