Earplugs. Our band director wears earplugs. So does the entire band. He turns the Dr.Beat metronome up as high as possible, attached to a Long Ranger speaker... INSIDE the friggin' band room. And turns it higher... and higher... and higher when the drumline starts falling behind or something. I don't see the point. He turns it up louder, half the girls stop playing and hold their ears, half the guys hold their ears with one hand and play with the other, and those lucky enough to have earplugs push them in further.
I'll have you know our band director is hard of hearing.
If I ever become a band director in my future, I won't use a metronone inside. I'll use my freakin' hands. At least I'll get exercise, unlike my B.D. now.