Trills: Pitch Focus
Some trills are easy, some trills are more difficult, and some trills are nearly impossible to execute cleanly. In the following example the B-natural to C trill is very easy. The C to D trill is more difficult because the pitch must be focused, by the lip, at a pitch center between those two notes. If your pitch center is focused below that "slot", some B-flat's may find their way into your trill. (Extending the 1st valve slide a bit will bring the pitch of D closer to C and the pitch of B-flat further away from C, and will improve the accuracy of the trill).
In the third example, however, it is almost impossible to find the "slot" between G and A. This is one of those trills where the player must actually move back and forth between the two pitches with the lip. (And to make matters worse, the player must perfectly synchronize that lip movement with the finger movement)!
One well-known instance of this G-A trill comes at the end of the first movement of the Hummel Concerto, when performed on B-flat trumpet. One good solution to the problem, of course, is to perform the work on E-flat trumpet, however this option not always possible for many students. A lip trill may be viable for some players, but by the end of the movement, fatigue may prevent many players from executing a lip trill with dependability. Therefore, the only solution may be to practice this trill enough to be able to coordinate the lip and finger movements.
Following is an exercise I wrote for a high school student of mine which seemed to help her develop this lip/finger coordination in preparation for her performance at our state solo contest. The first few measures require only a small amount of lip movement, but as the exercise ascends, more and more lip movement is required to focus the pitch of the "trill" and, of course, this lip movement must be coordinated with that of the fingers. Because the notes start slowly the lip/finger coordination is easy at first, but the coordination becomes more critical by the time we are playing sixteenth-notes.
