First documented from as early as the 16th century, vibrato is a musical term used to describe a change between two pitches that occurs in a consistent, wavering pattern. When the speed and variation of the oscillating pitch are altered, different effects are created and these changes add character and affect the mood of the musical piece being performed. Change that occurs in pitch speed is referred to as the "rate of vibrato," while the amount at which the pitch is varied is called the "extent of vibrato." The musical effect is implemented both during singing as well as when playing a musical instrument.
To achieve vibrato during singing, it is important that a singer achieves the right amount of pressure in each breath. This is accomplished by using the abdominal muscles and other areas of the support system, such as the lower lumber muscles. By implementing these muscles, the musical effect results in what is often referred to as an "open throat." Open throat occurs when the pharynx or throat, which connects with the nasal chambers and the mouth, opens. It also results in closed vocal chords, and it is the combination of the closed chords, open throat, and breath pressure regulated by the support system that creates the oscillating effect.
A singer can improve vibrato by practicing musical performance techniques so that the musical effect becomes a natural part of singing. One common and simple technique involves placing hands below the rib cage and gently pushing in and out while singing a note at one pitch. By using this technique, a singer is able to produce a wavering effect and can practice changing the speed at which the note oscillates between pitches. An effortless flowing vibrato will be created when a singer can change between two pitches approximately six times per second.
While the musical technique is popularly associated with singing, it is also implemented when playing a musical instrument. Like singing, instrumental musicians will waver between two pitches of a note in a technique called "finger vibrato." To create this effect on a string instrument, a musician will hold down a string and play a note while moving the string up and down on the fret board. Similarly, the effect can be achieved on a woodwind instrument by placing fingers on and off of the holes of the instrument in a quick, vibrating motion, or alternatively, by modulating the amount of air flow into the instrument. Air modulation is achieved by moving the tongue backward and forwards in the mouth, or by controlling the throat and abdominal regions.
Brass players can also achieve a wavering between two pitches by either changing the embouchure, or tension of facial muscles, or by shaking the instrument in a back and forth motion against the mouth. By changing the embouchure and altering the shape of the lips or jaw position, brass players are able to achieve “lip vibrato.” Alternatively, by shaking the instrument back and forth, the amount of pressure between the lips and mouthpiece is altered, which also creates an oscillating effect.