Vibrato is a fluxuation in the pitch of a note. When playing with vibrato, flutists bend the pitch of a note up and down by alternating using lots of breath support, and just a little breath support.
How does it work?
Vibrato can be created in one of three places- with your diaphragm muscles, with your throat/windpipe, and with your mouth/lips. Flutists do not use the mouth/lips way to play vibrato because we need to keep our lips in the right position for our embouchure. Some flutists will use the diaphragm and some will use the throat; this is a matter of personal preferance.
How do I learn vibrato?
Pant like a dog. The muscles you are moving are your diaphragm muscles. Try playing long tones on your flute and moving the pitch up and down in wide, slow waves by contracting and relaxing these muscles. Use a metronome to gradually increase the speed of the waves. You should always be able to vary the speed and depth of the waves, and the sound should be constant between the waves, with no breaks in between them. Your private teacher can help to make sure you are doing this correctly.
When should I use vibrato?
There are two varying schools of thought on this one. Some people say that every note should have vibrato because vibrato improves the tone and makes it more beautiful- so by playing every note with vibrato, you are making every note beautiful. Other people say that vibrato is a decoration that should create contrast in music- between the notes with vibrato and the notes without it. I tend to use vibrato on most long notes, and skip it for shorter ones. I also tend to use more vibrato when playing with other people and other instruments then when I am playing solo music.
What about vibrato speed and depth?
You can make contrast with your vibrato by changing the speed (how fast the waves are) and depth (how wide the waves are, how much the pitch changes). This is mostly just something to experiment with, although in general, it's good to use faster, narrower vibrato for high notes and wider, slower vibrato for low notes. The speed and depth can also portray the mood of the music (ie wider vibrato for sad mood, faster vibrato for happy stuff).
What can I do at the very beginning or end of the piece?
Another interesting thing to experiment with is tapering vibrato at the very beginning or end of a piece. Sometimes, it's good to start a note with no vibrato, then gradually add a slow, shallow vibrato, and crescendo as you increase the speed and depth. The ending of a note could be the reverse- gradually slow the vibrato and make it narrower as you decrescendo and fade away. I have also heard the reverse used successfully- increase the speed of the vibrato as the note dies away. This is something to experiment with and use to portray the mood of the piece.
Vibrato Comparison
If it seems like flute players use tons more vibrato than other instrments... Here's a very scientific chart that compares the instruments and how much vibrato they use.
opera singer
flute
saxophone
oboe
trumpet/high brass
low brass
choir/pop singer
clarinet
piano
Least Vibrato
