WHAT I MADE FOR MY CLASSROOM | classroom decor, organization & assignments 

The voice level system is useless overall imho. At the beginning of the year, I explain what each time block means and they stick with it usually with few reminders. Work time is quiet time. If you need to talk for discussions your deskmates (I always group) should be the only ones hearing you. Using the library means your voice is off. Stuff like that gets my class to be more controllable than any voice level me or my colleagues try.