A threat to the musicians from the conductor, ie. play or else...
The conductor was prepared to give a preparatory beatdown if the flutes started early one more damn time.
The length of time it takes for a piccolo to stay in tune.
James: "Hey, I think that piccolo player stayed in tune for a whole note!"
Alex: "No, silly, everyone knows piccolo players can only stay in tune for a half note."
The quietest volume a trumpet can play at.
Derek was a trumpet player, and was physically incapable of playing quieter than fortissimo. That was a good thing, since it meant the rest of the band's mistakes were not heard, only his own.