| Vibrato is a natural development of a (mostly) subconscious physical technique to help color and enhance your sound. Different styles of music call for different types of vibrato. Some are fast, slow, narrow, wide... listen to as many different kinds of singers from opera to country and western and you'll hear each one do something different. I developed my vibrato subconsciously by listening to the great Rafael Mendez. I stopped using vibrato for almost a year at my teacher's request and when I started again it was slower and I could vary it with a better understanding of when and how I should use it.
I truly don't believe you should bother with the "how to's" of it. I think you should allow yourself to be inspired by what you are presently hearing and see if your talent for imitation is working. Potentially great musicians need to be good mimics when they are young. It's a way of exercising your ears. Do you ever do Napoleon Dynamite impressions? Well, you don't think about how to manipulate your vocal apparati to do it, right? Same thing with vibrato. Hear it and adopt it as your own. you'll develop your own style soon enough. You should be doing a lot of singing at your stage in as many styles as you can. It doesn't matter what. Rap helps develop a sense of pulse and timing but you need melody and harmony to start creating your sense of pitch.
Do you have any opera recordings. If not, go pick up a "Best of" type CD with Pavarotti and listen and when you're by yourself, sing and imitate.
Good luck and listen.
ML |