David Bowie has a fast one. Mary J. Blige has a slow, sultry, one. Maynard James Keenan doesn’t have a trace of one. Singing with vibrato is a matter of taste. Having a choice is a matter of control. For most singers, the subtle, rhythmical movement of vibrato feels more like fate. When you want vibrato, it hides on you; don’t think about it, and it shimmers on the end of a note. Vibrato brings vitality to a voice. Sound without variation is boring. Compare a refrigerator to a fly buzzing around. The steady hum of the compressor quickly becomes background noise while the bug gets harder to ignore. With the exception of rappers and singers like Beck who don’t sustain notes, those without vibrato tend to rely on overdrive to create excitement. This often leads to blow outs. The more vocal colors available on your pallet, like vibrato, breathy, nasal and gritty, the easier it will be to paint an interesting portrait of a song without killing yourself.
The mechanics of vibrato are simple and reflexive, which is what makes it so elusive. Picture the fret hand of a guitarist sustaining a note. The finger movement alters the length of the string creating a slight waver in pitch. Things are just a little more complex with the voice. Like a stringed instrument, the tension of the vocal folds is varied rhythmically, creating movement in pitch. Along with this tension change, though, is a variation in the thickness of the vocal fold. The combined movements of pitch, volume and tone are what set vibrato apart from tremolo (change in volume only) and wobble (change in pitch only).
Tension squashes vibrato. Not just the obvious neck bulging stuff, but subtle everyday stiffness can neutralize it as well. Like the freedom required to wiggle your finger when sustaining a note on guitar, vocal vibrato requires muscle independence. Backing off the air pressure is the first step to releasing your voice. Let the ability to produce vibrato be your guide. Lay down flat on your back and place your hand on your belly button. Breath so that your hand rises and falls. Now sing a comfortable note and look for the presence of vibrato. If the pitch is stiff notice what your abs are doing. Are they contracting to drive the note? Check the behavior on various pitches. If you push too much from your stomach, the muscles surrounding the larynx will brace and vibrato will be lost. Reduce the volume and try again. The goal is to reduce the air pressure to the point where flexibility is found. Don’t be alarmed if this only happens at very low volumes. With practice, you’ll be able to increase the volume without loading the neck with pressure. Strike the proper balance during a song and vibrato will blossom. That’s why it tends to come in at the ends of notes; once we feel safely on pitch, we ease off the pressure a bit.
Another check for vibrato-eating throat tension is to rotate your head in a small circle when singing. Pretend you are tracing the outline of a quarter with your nose. Does the rotation stop when you begin to sing? Is it stiffer on high notes? Again, reduce the volume until you find the correct air pressure. Neck tension is not a requirement of singing loud or high. We often see singers so locked up in the neck that they literally have to shake their heads or jaws in order to create vibrato. In the same way, a guitar player who needs to shake the guitar to move a note must be applying a death grip on that fretboard. There’s nothing wrong with using force to make a strong statement. Too often, though, the statement it makes is that we are overcompensating to mask weakness. Be brave and do the dirty work in private. Use vibrato as your guide and discover the power within.