Even for those who are unaware of what vibrato is, they recognize its presence or lack of it. Vibrato is one of the most distinctive characteristics in vocal tone and a healthy one makes a voice attractive and accessible. On the other hand, any vibrato drawing attention to itself is generally considered less appealing.

What is Vibrato? Healthy vibrato is a fluctuation of pitch on a single note. It is created by nerve impulses that cause pulsations in the vocal box.

Vibrato caused by nerve impulses is heard less as pitch changing and more as a tonal quality. If you sing vibrato on the note ‘A,’ for instance, the pitch fluctuates up and down while still sounding like an ‘A.’ Less effective methods of vibrato involve consciously changing a single note’s pitch.

Healthy Vibrato: Vibrato is characterized by both its rate, how fast or slow vibrato is, and range, how wide or narrow it is. A healthy vibrato is temperate and uncontrolled. The ear perceives it as neither too fast or narrow or too slow and wide. It adds vibrancy and life to the voice, makes it unique, adds color and richness, and is constant unless singers stylistically choose to use straight tone.

Tremolo or Bleating Vibratos: When a vibrato in the voice is too fast or narrow, it gives off a bleating or shaking quality and is referred to as a tremolo. An example of a fast, slightly narrow vibrato, though not necessarily quite a tremolo, is Snow White’s voice in the Disney film. Usually a tremolo is caused by excessive tension or when a student tries to control the pitch change in vibrato.

Sometimes tremolo occurs only in a certain range or at the end of a sustained long note.

Wobble: Vibrato can also be too slow and wide. Older singers who have let their training go can develop it, and often when people poke fun at opera singers they imitate a wobble, though good opera singers do not sing with one. Wobbles are caused by both rigidity and weightiness in the breath support. Singers with a wobble may start a singing tone beautifully and then a wobble creeps in as the note or phrase continues.

Straight Tone: The opposite of vibrato is straight tone, where a singer’s tone does not fluctuate in pitch on a single note. Straight tone usually indicates an immature, not yet developed voice or someone who sings by vibrating only the edge or a portion of the vocal cords. Straight tone is corrected by teaching proper breath support and phonation, or the ability to use the vocal cords in an efficient way. Some voice teachers may recommend oscillating pitch consciously to correct straight tone, but that does not create nerve impulses involved in healthy vibrato.

Is Vibrato Always Appropriate? Choral conductors may ask for a straight tone and some styles of popular music, such as certain types of jazz, stylistically demand it. Some singers find it nearly impossible to eliminate vibrato without creating tension, because they attempt to control it by restricting the vocal cords themselves. Advanced singers find it easier to create a straight tone by singing with less volume and vibrancy or by singing ‘on the edge’ of their voices. At times people do not recognize vibrato in popular music even when singers use it. This perceived straight tone is actually not without any vibrato whatsoever; it is just unnoticeable to the untrained ear. Operatic or classical singers sing with more power and volume in order to project throughout a hall without electronic amplification. Singing in full voice makes vibrato more common and noticeable.