however! here's a chart showing the difference in frequency between each midi note and the frequency of the tone *nearest* to that midi note that it's possible for the game boy to generate. you can see that there's actually a fairly small range of midi notes that can be approximated by the game boy without sounding "out of tune" (depending on what you consider to be out of tune. no one except whiplash guy is going to notice 2–3Hz, but 100Hz is obviously going to not sound right)