I guess this has been around for a while but I have never seen it. Its pretty amazing and definitely awesome.
Check it out, Animusic
Bill
I’d never seen it either… very cool. So you going to recreate it in Unity? 
Someone definitely should!
You would have to make some plugin for unity to read midi information from some music making program and then write algorithms for each instrument. It would be impossible to time right with a coroutine. But yeah I suppose possible.
Bill
not really, you could impliment it with a library of all the samples in unity and then call them like any audio file…you could have the pre composed midi track running externally, or even use midi instruments/controllers (keyboard or pads etc) to send the note info to unity…