Pure Data — PD Community Site
It's kind of hard to explain exactly what it is. But pretty much it's "visual" programming for sound and sound synthesis. I've only learned some basics but like it's reallllly beautiful. I'm about to play with it again right now haha. The sounds I've made so far like vibrate my labtop it's weird and awesome.
here's a basic example:
I've been looking for something like this for a while, because I often get frusterated by the limitations of soft-ware and just wish I could literally make sound waves, This so far is the closest thing to find what I've been looking for.
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It pretty much allows you to easily make your own music soft-ware with little to no limitations
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Best tutorial site I've found!
http://www.pd-tutorial.com/