Question: How do I improve my tone quality?
Answer: Developing a more beautiful tone is a complex matter with many variables that include air speed, air pressure, air direction, aperture size, aperture shape, embouchure flexibility, the attack you use, and posture. The goal is to single out each of these variables and work to make them efficient and productive. This will lead to long-lasting improvements in your tone quality.
In gym workouts training is divided between muscle groups, and the same should be true in flute practice. The following are exercises for each area. Each exercise should have a clear target and should be as simple as possible. The most useful exercises are the ones that focus on only one area at a time, so you can find what works best for you.
Play slurred arpeggios for two octaves, ascending and descending smoothly. This teaches air speed control. Because the intervals between each note are rather small, try adding the seventh for a major or minor 7th chord or a full diminished chord. You should be able to play these with only micro changes in the embouchure and you can focus on slightly increasing the air speed as you play up the chord and decreasing the air speed as you descend.
Think about playing these arpeggios as climbing the stairs with each stair representing a note. As you climb each step, increase the air speed slightly. Since this exercise is about the air, try to keep lip movement at a minimum and use no vibrato.
The best way I have found to explore air pressure is to lean against a wall with the left elbow only. Play a note as you slowly push the wall with your elbow. If you do it correctly, you will be able to notice what happens inside you, especially around your chest. In order to push the wall away, you have to increase the pressure of the air inside you. Then try to create the same feeling away from the wall.
The lips are responsible for controlling the direction of the air. Put your hand in front of your mouth (about a quarter of an inch away). Slowly direct the air upwards towards the fingertips and then back down to your wrist. Practice this a few times and then repeat this movement with the flute.
Aperture Shape, Size and Position
Play a long tone on a first octave B or Bb. Experiment with changing the shape of the aperture. Use a mirror to enhance your success. Explore making a horizontal elliptical shape to a vertical elliptical shape. Also experiment with the depth of the aperture by pushing the lips forward and then back. You might find a better position for the lips than what you have been using.
Octaves are the ideal workout for developing embouchure flexibility. Play octaves in various controlled rhythms and make sure to change the notes with your lips only, while keeping your air stream unchanged. (See Flute Talk, February 2018 for more ideas about this.)
There are four main ways to attack notes – with your tongue behind your teeth, with your tongue between the lips, with your lips only (pa, pa) and a with breath attack (no tongue). Practice passages with each of these ways. Practice these attacks with scales and arpeggios. Vary the dynamics, exploring from forte to pianissimo.
As a final word, I recommend that instead of practicing tone quality or aiming at improving your tone quality, focus instead on improving each of these variables. Work on each one separately. You will be surprised to find how much your tone quality improves in this way.