In the pitch part, what do the numbers mean after the note? I was thinking it's the octave range but under preferences, under Base Note(what is that, by the way; it doesn't seem to change anything when it's altered), you can go up to -2, so that doesn't make sense. Also, is there a way to change the note octave that get played? Because only learning the pitch of only one octave set doesn't make sense. And one last thing, what's the difference between the free version and the paid one? On it's description, it doesn't make sense when it says it's limited to one level.