I was asked this week about my thoughts on developing and using vibrato.
It is an important skill; however you can place too much emphasis on it and create unnatural vibrato that's hard to unlearn.
In my professional experience, it has everything to do with developing breath support/control, learning to use a feeling of compression centered in the pelvic floor, AND sending this breath through an open and relaxed throat. Then you find yourself with control of all kinds of vocal choices, vibrato being one of them.
My course (at www.judyrodman.com ) includes an old exercise called "Messa di Voce" in which you hold a tone as richly as you can. Once you master this exercise, you can try backing off the pressure even more and allowing a little controlled vibrato to begin in the middle of the sustain. Then for even more control, you can try and smooth the vibrato out into a straight tone again. Jazz singing requires great control of vibrato; you MUST learn to back off pressure while sustaining support, "spinning" the tone in the back of your head to give ultimate control.
Put the back of one of your hands on your tailbone. Stand tall and flexible with head back and chin level. Take a breath into, and sing out of, a spot deep in the pelvic floor just in front of your tailbone. Hold a tone steady. Don't lean forward; use so little forward pressure that it almost seems you're inhaling the tone. Then try THINKING a sweet, even vibrato and just imagine it..."will" yourself to do it. Let it come naturally... it's SO IMPORTANT NOT TO FORCE VIBRATO TO OCCUR. As you gain experience with it, try allowing it to occur without thinking.
IF you don't lean on your voice or push too much air, AND you support your tone, I think you'll find yourself with a vibrato you can control naturally. Above all... DON'T JUMP ON YOUR DIAPHRAGM and try to make vibrato that way.
Another thing you can do is to mime a singer who has the natural and free vibrato you want. Watch out for mimicing bad technique from singers whose vibrato is too fast, too slow and wobbly, or uncontrolled and forced.
I have found that this is all my singers need for the vibrato they want to use. I will, as always, be learning more about the voice and will pass other information to you as I find it useful.
Let me know how effective you find this exercise by clicking "comment" below this post. I also value any of your own thoughts or experiences you have with vibrato and it's control.