Possible Clues:

• Lesson at academy produces musical work
• A boy at a composition, by the sound of it
• Beethoven's "Appassionata," e.g.
• The "Moonlight," e.g.
• Opus
• Beethoven's 'Moonlight', for example
• Accord competitor
• See 38-Across
• Not as jazzy a composition
• That's your boy at a bit of music