Alex Ruthmann, in a blog post discussing music-making with the educational multimedia programming environment Scratch, has this to say:
What’s NOT easy in Scratch for most kids is making meaningful music with a series of “play note”, “rest for”, and “play drum” blocks. These blocks provide access to music at the phoneme rather than morpheme levels of sound. Or, as Jeanne Bamberger puts it, at the smallest musical representations (individual notes, rests, and rhythms) rather than the simplest musical representations (motives, phrases, sequences) from the perspective of children’s musical cognition. To borrow a metaphor from chemistry, yet another comparison would be the atomic/elemental vs. molecular levels of music.
To work at the individual note, rest, and rhythms levels requires quite a lot of musical understanding and fluency. It can often be hard to “start at the very beginning.” One needs to understand and be able to dictate proportional rhythm, as well as to divine musical metadimensions by ear such as key, scale, and meter. Additionally, one needs to be fluent in chromatic divisions of the octave, and that in MIDI “middle C” = the note value 60. In computer science parlance, one could describe the musical blocks included with Scratch as “low level” requiring a lot of prior knowledge and understanding with which to work.