Great question, though I dont know the answer.I look forward to informed replies. At home I have a Yamaha 8-track set up, which is a great musical notebook, and also can be used to produce perfectly adequate quite complex CDs. But out of the house, I rely on drawing music staves in my trusty little note-book in my trouser pocket, and jotting down ideas there. I'd be intrigued to know of anything equally small that could be more useful.