I have been using the "Tonal Energy" tuner and metronome app in all band classes. IMHO, it is the best tuner out there (mostly because it has a smiley face when you play in tune - gamification at its finest!). Many HDMS band students have asked me about it, and fortunately, it is available in …
Tonal Energy Tuner and Metronome
High Desert Middle School Band 