An exercise I use and recommend to my students based on ideas from:|
"Tone Development Through Interpretation" by M. Moyse.
- play slowly with a strong and well focused tone on all notes.
- keep the air stream moving at a constant rate and move your fingers as legato as possible.
- as the intervals become larger allow your lips to move enough to get the top note but don't over do the lip motion.
- repeat each bar until you can play the intervals both up and down with complete legato.
- increase your speed only if the intervals (especially downward) are working well.
- after working on this set of notes then proceed on by changing the starting pitches of each measure to C# & D, then D & Eb, then Eb & E, etc.
- once you have worked this to the point where the final exercise with an octave in it is very smooth and easy to execute well then increase the range upward until you reach the double octave.