Flute Harmonics: What, why, and how
What are harmonics? Why do flutists have to understand them? Are there exercises that use harmonics?
Note that the terms “harmonics,” “partials,” and “overtones” refer to the same phenomena.
With only three valves, it’s easy to understand why trumpet players would need to understand the overtone series. Less obvious is why this information is important to flute players also.
My favorite exercises using harmonics, also called the overtone series, are included in the warm-ups in Flute 102: Mastering the Basics by Patricia George and Phyllis Avidan Louke.
Another great exercise for developing flexibility and breath control is practicing whistle tones. Whistle tones can be played on any note. When first trying this exercise, try fingering a note in the third register, perhaps a high B-flat. Blow a very soft but consistent stream of air using a regular flute embouchure. If the angle, direction, and speed are correct, you will hear a ghostly whisper or whistle. This is not a regular tone but something high-pitched and ephemeral.
Once you are able to make a sustained whistle tone, use the fingering for a low note, perhaps the lowest D. Now you will be able to play several different pitches when slightly adjusting the air. These pitches are the overtone series. The fundamental, or lowest note, is often the most difficult to sustain.
When you feel comfortable producing whistle tones, try these exercises:
Have fun, be curious, and stay flexible!