There’s a webcomic called Soul Symphony that’s about a group of music kids. It’s a fantasy/action/comedy about an anti-social clarinet girl in high school who helps out her classmates by going into worlds inside their souls and fighting monsters with music-based magic.
You can read it here: www.soulsymphonycomic.com
It’s written by a music kid for music kids. A bunch of band, orchestra, and chorus kids from my school read it and seem to like it, so I think the world of music tumblrs will too!