Have you looked to see if there isn't already an
application in
development that could suit your needs? You might even be able to help
in the development of something like Rosegarden or Muse or Ardour.
Well, I need to do it for the university. So, in a way or another, I
have to build something :D
I was thinking to use C++, but I don't know from where to start. I
mean, I know the language, but I don't know how to process sound with
it.