Should the horn vibrate in the upper register? When I play from Fsharp to G on the staff, I know when I'm playing a full, resonant note by the subtle vibration of my horn and valve casing. However, once I play above G, (notes like A,B, and C) I can't get the horn to vibrate. Is the lack of vibration a sign that I'm not playing the note as efficiently and resonantly as possible? Or is it common for the horn not to vibrate on these notes?