If you watch the
Brass section of any
orchestra, you'll eventually notice that the
Tuba is the only instrument that is not aimed so the
bell of the
instrument faces the
audience. Instead, when its played upright, the tuba faces upwards.
Upon asking a music teacher, I found the reason. Tubas are very loud when played, and having the bell aimed forward like a trumpet or a french horn would drown out most of the orchestra.
Aiming the bell up means it doesn't directly get to the listener's ears, but it does allow an Orange to get dropped in, lodged, and become extremely difficult to remove.
Not that that's happened to me.