Well, if the narrator has been established as a musical prodigy, it’s not out of place for him to talk a lot about music and his relationship with it. 

Don’t underestimate your audience (a tiny bit of google exercise is good for them), but try not to make your writing look like a musical theory textbook. Technical -words- hurt no one. Saying that ‘I ignored him and went back to contemplating arias’ isn’t likely to throw people. Just don’t write it mechanically, in a way that makes it gibberish to non-musicians. 

In addition, a good way to talk about things in general so that your audience is not overwhelmed is to talk about an experience in terms of feelings, rather than writing a list of things that are happening like a cookbook of ‘tell’ writing. Talk about the mood of the music. If he’s using it as a calming device, contrast it with the situation.

 Most of all, focus on your ‘show, not tell’ writing. Here’s practice: Grab a piece of music that you like. Describe it two ways, first in a technical way that’s all about crescendo and decrescendo and each little staccato and what key it’s in, and about the little birds’ eyes that’ll watch and laugh at the poor woodwinds and brass. 
Next, write about the feelings of the piece. The tone. (I was once supposed to make my flute sound ‘yellow’…) The effect it has on your blood pressure. What this piece reminds you of. 
Then, hand both to a non-musician friend and ask them which they like better. Chances are, the second will be better.

Hope that helps you. 
- Evvy