I’d like to open with some inspiring words by Sax player Jack Wright

In the early decades of free improv, when new techniques were the mark of a fresh approach to traditional instruments, they were often considered the new standard to be displayed. But at this point I find players using a more integrated technique, where nothing is “extended” because no technique by itself connotes a radical departure. […] [N]ow every technique tends to be subordinate to the direction of the music, and pyrotechnics are not flashed as a distinctive badge of mastery. Of course, there are some in every audience who will be impressed by circular breathing, the kind of “look, ma, he ain’t breathing!” reaction, but if we want to stay on course we know we aren’t about impressing people but rather opening up our musical hearts. And for me, this opening calls for the hugest range of sound the imagination can wring out of body and instrument. [From an interview with John Berndt]

The study of extended techniques as an extension of good traditional technique and good practice habits gives our imagination wide scope for expression. Studied carefully, they will help to strengthen many aspects of flute technique: embouchure, air flow and the cultivation of patience! Below are some of the benefits and applications that I have discovered myself and collected from others:

• Harmonics. Benefits: embouchure strengthening and development, improvement of upper register, especially articulation of quiet attacks, familiarization of “natural” tuning, finding the correct angle of a note, and their use as “alternate” fingerings
  Applications:
  • to relieve stuffy notes – take a high note that tends to stuffiness such as G#3. Play it first mf sustained. Then play it as a harmonic of C#, then as a harmonic of middle G#, then as a harmonic of E, then as a harmonic of low C#. At each step, play the note sustained, then with repeated articulations: single, double tongued, and flutter tongued. Listen to the intonation as well. Note how much or how little you have to do to “correct” it.
  • for third-octave rapid passages, use harmonic fingerings for ease and improved intonation
  • when playing alto or bass flute in the third octave, I almost always use harmonic fingerings as the “traditional” ones are inevitably too sharp.
• Singing while playing. Benefits: opening of the sound, improvement of the sense of pitch, control of air flow
  Applications:
  • as an exercise for hitting high notes: sing and play low C, then blow up through the harmonic series. To reach the highest C, notice how you needn’t sing louder. The speed of the air is what produces this sound. You can create that speed by moving the lips forward – like you would sqeeze the nozzle of a garden hose to get the water out in a faster stream. Find the correct angle, focus your energy at the pelvic floor (as if you are about to cough) and blow! But notice how you can keep your throat relaxed: keep singing.
  • throat tuning to help smooth out potentially “bumpy” intervals – such as (above the staff) E down to A.
• Multiphonics. Benefits: embouchure refinement and strength, control of air pressure and speed, control and awareness of angle of air column
  Applications
  • as an exercise for refinement of quiet tones: push the flute in all the way and play multiphonics of very small intervals (see Exercise L: Robert Dick Tone Development through Extended Techniques). My method is to play the notes separately and refine the sound of the upper note first. Once you have refined it – remember the air speed, this is the one you will need. It can’t be weaker and still produce the upper note! Then by changing the angle of the airstream find the lower note. (This is Robert Dick’s advice, then he further suggests to tune your throat to the weaker pitch.)
  • as an exercise for opening up the sound – (pull the flute back out if you have pushed it in) – play muliphonics of large intervals (see Exercises D and Q: Robert Dick Tone Development through Extended Techniques). For these intervals it helps to think of having a “tall” embouchure, the upper lip controlling the upper note, the lower lip controlling the lower note.
  Tip
  • When you need to hit a stable multiphonic in an ensemble situation, it is often advisable to aim for the top note and don’t let it waver, otherwise it will sound like a mistake. (For example, the multiphonics in Xenakis’ Jalons.) Of course, make the sound as rich as you can by including as much of the lower tone(s) as possible
• Whistle tones. Benefits: control and awareness of the lip’s aperture, control of very slow air-stream
  Applications:
  • as listening and refining exercise choose a low note such as low C, play whistle tones carefully seeing which notes of the harmonic series you can pick out. To find the proper resonance, whistle the normal way – this prepares your oral cavity for the right shape of the whistle tone.
  • as a relaxing/de-stressing exercise: work on controlling slow air streams by practising low whistle tones. Your embouchure has to be very steady because there is little air behind it to support it. (Patience: It took me a long time to get to low C!) This is another case where thinking “tall embouchure” helps. It also helps to think of having a cushion of air behind your lips (i.e., your lips are not too flat against your teeth) and to relax your jaw. Once you can do this reliably, it is a good de-stressor before going on stage.
  • if you have trouble producing a fourth octave note, find the correct angle by first finding the whistle tone (you may find yourself rolling out more than usual), then blow. It should help.
• Circular breathing. Benefits: development of the larger muscles for embouchure flexibility and stamina, ability to play longer phrases in moving passages.
  Applications:
  • in classical repertoire, one can use this for rapid or trill passages. I like to use it for long cadential trills because you can give full power without fear of having not enough air for the final note.
  • as a checkpoint for resonance. When I am warming up or just about to go on stage, I check my circular breathing regardless if it is required in the piece I am about to play. This is a sure-fire test to see if either of my nostrils or the back of my throat is blocked. If I am clear enough to circular breathe then I should be able to play with maximum resonance!

To approach a given technique musically, ask yourself (or by all means the composer):

• is the technique used to create a certain atmosphere?
• does it evoke something concrete?
• does the technique play a role in the form of the piece?