I wrote these exercises for a long distance student of mine named Bryan Qu. I can't say enough about the importance of working with drones. It's much more effective that just playing long tones because you are working on pitch at the same time you are working on control and support. Working with a drone allows you to really focus in on micro-fluctuations of pitch. It also can help to develop pitch memory, which ties in to oral tract position memory. When you spend time with a drone you start to remember how different notes feel and sound.
As we develop our sense of pitch we can learn to experience pitches as a single point, rather than as a range of frequencies. What I mean is that most of us do not know pitches as an exact rate of vibration. For example, we might know that we need to lip down a little to get our high Eb in tune and we may know when we are close to getting that note in tune, say within a 4 cent range (2 cents in either direction). This would be considered to be pretty respectable by most standards, but it could certainly be improved upon.
Playing long tones with a tuner doesn't engage your ears like working with a drones Working with drones is the most effective way to really dial in your intonation as well as gaining control of your sound. There are several different exercises that you can do with the tuning CD and they should be incorporated into your continuing daily practice routine. I usually only have two different categories of sound/intonation/control exercises that I have my students do: overtone exercises and tuning CD exercises.
1. Long tones with the drones-
a. Play long tones over the entire range of your horn with the drones. Strive to keep your hands and embouchure totally relaxed while taking complete inhalations and playing each note as long as possible. Play at different volume levels while trying to keep your notes perfectly in tune with the drone. The main purpose of playing with drones is to try to rely only on your ears to play in tune, but you might want to also try putting headphones on and using a tuner to check your pitch. The tuner is a crutch ultimately; so do not depend on it for intonation. Make sure you also go into your altissimo when doing these long tones.
b. Next play intervals with the drones. Try jumping octaves while keeping the pitchperfectly centered. After 8vas do 5ths, 3rds, 6ths, 4ths, min 3rds, in that order. Play unison with the drone, then skip to the interval, and then back to the drone. You need to learn to keep every note on your horn in tune when skipping from every other note.
2. Pitch bending exercises with the drone-
a. Start with a concert E drone. First play your high C# and center it. Then finger a palm key D and bend down to a C#. Hold this note and center it perfectly in tune while playing it as long as you can. Try to be conscious of an open and relaxed throat, rather than just a lowered jaw. Do long tones in this manner in descending half steps. You will find that some notes are much easier to bend and stabilize than others.
b. Do the same thing as the prior exercise, but bend down from a whole-step above each note instead of a half step. Do not worry if some notes do not stabilize, the very act of trying will improve your control.
c. Wait until you have mastered the first two pitch bending exercises before doing this third exercise. This time finger a minor third above each drone note and bend down. Remember to always first play the drone note to get it firmly internalized before fingering the higher note and bending down. These bending exercises force you to learn to play with a relaxed open upper oral tract and to get used to using no upward pressure on the reed. They also greatly increase the difficulty of playing long tones in tune with the drone and force you to internalize the pitch. They also help stabilize pitch in the palm key register where you are constantly required to lower the pitch to play in tune. As you try this minor third pitch bend exercise you will find it impossible to do in the lower registers of the horn.
3. Improvising with drones-
Try improvising freely using the drone as a pedal. Try many different modes against the drone and occasionally return to play a unison or 8va to make sure you are still dialed in. Practice switching smoothly between every different type of minor scale against the drone. Practice playing totally chromatically and resolving smoothly to the pedal note.