Circular breathing allows one to continue breathing in air without disrupting the sustained note(s). This is the most difficult of the extended techniques to master. Composers should not assume that every player has mastered the technique. It is easiest in the higher registers and on sustained trills.
Circular breathing allows one to continue breathing in air without disrupting the sustained note(s). The technique of circular breathing can be divided into four parts:
1. Normal tone production
2. Adding more air to the mouth and throat, while still keeping a good focused sound. At this stage, the lips have to help a little more to keep the embouchure in correct shape.
3. The air stream from the lungs is interrupted in the throat, and the sound is produced entirely by a "mechanical" movement of the tongue and cheeks. Simultaneously, the player is breathing in through the nose.
4. The throat is opened (it feels almost like swallowing), and the airstream flows directly from the lungs to the embouchure.
Step 3 is the most delicate step. It is against our reflexes to breathe in while the air inside the mouth is pushed into the flute (through solely tongue and cheek movements). This step has to be practiced separately in order to breath in enough air in a short amount of time. It is not a deep breath where the abdominal muscles relax. It is a breath taken on top of the air which is left in the lungs, almost as if you were breathing into your shoulders. The expelling of the air with the tongue and cheek movement has to last as long as breathing in during step 3 and change of air direction.
Circular Breathing demonstration