You donít have a retention problem as much as you have a PR problem. There are things you can do and try, but in my experience there are long term image problems that are impossible to overcome in some schools. Here are some things I have to done to correct some of issues youíve talked about.
1. Created a small pep band (mostly leadership kids) to play at a few volleyball and basketball games.
2. Let the drummers come up with a fun skit/ensemble to do at the black out pep rally, usually with trash cans or other silly stuff.
3. Making a point of saying hello and making small talk with kids who quit band.
4. Let my kids play some of the annoying stand tunes that I hate because the football team or student section likes them.
5. I go to sports games that Iím not required to go to with my kids and congratulate students on a good game and shake their hand, whether theyíre in band or not (and I try to say their name when I do so).
6. I spend time in the main hallway and front office getting to know students who arenít in band. I do this daily.
Now, none of those things will matter in a community with a lifetime of treating band kids like garbage. Toxic communities are just that, thereís no magic switch. Good luck!