Tokyo Avengers.

The eleventh grade went on a field trip to a music school where everyone plays their own instruments and, if they want, they can form their own band and ask the teacher to set up a stage for their concert. The music teacher's name is Derek Whiter, and the school teacher's name is Ryuki Imezo.
Ryuki Imezo: Children, please do not distract the guys from rehearsal or your own business.
All the eleventh-grade kids and their teacher entered the music building. Everyone ran away and looked at everyone else. But Draken, Mikey, and Mitsuya were attracted by your appearance and playing your instrument.