  Motion of the keys was measured in a transverse flute while beginner, amateur
and professional flutists played a range of exercises. The time taken for a key
to open or close is typically 10 ms when pushed by a finger or 16 ms when moved
by a spring. Delays between the motion of the fingers were typically tens of
ms, with longer delays as more fingers are involved. Because the opening and
closing of keys will never be exactly simultaneous, transitions between notes
that involve the movement of multiple fingers can occur via several possible
pathways with different intermediate fingerings. A transition is classified as
`safe' if it is possible to be slurred from the initial to final note with
little perceptible change in pitch or volume. Some transitions are `unsafe' and
possibly involve a transient change in pitch or a decrease in volume. In
transitions with multiple fingers, players, on average, used safe transitions
more frequently than unsafe transitions. Professionals exhibited smaller
average delays between the motion of fingers than did amateurs.
