VIBRATO - Viola vibrato is similar to vocal vibrato -- it's a slight and rapid fluctuation in pitch (controlled oscillation), and is used to add warmth and expression to music. There are three types of vibrato: finger, hand, arm or a combination of all three. Since the viola is a larger instrument than the violin, some violists find that viola vibrato is a wider vibrato that uses more of the arm than violin vibrato, but this is a matter of personal preference. Variations in the width and speed of the vibrato can produce a wide range of expression.
The following definitions are excerpts from the great violin pedagogue Ivan Galamian's book Principles of Violin Playing and Teaching, and explain the three types of vibrato in more detail:
Hand Vibrato: "In this type of vibrato, the hand swings from a more-or-less immobilized arm...the finger elongates itself as the hand swings backwards toward the scroll and then resumes its original curved position as the hand returns to its starting point." (p. 38)
Arm Vibrato: "The impulse, instead of coming from the hand, now comes from the forearm, and, in this case also, the finger has to yield passively. The finger should be firm enough to hold the string down and to retain its place on the string, but flexible enough to submit to the motion of the arm. It must stretch and recurve with the backward and forward swing of the vibrato cycle." (p.40)
Finger Vibrato: "The impulse comes from the finger itself, which swings from its base knuckle with the hand slightly yielding and moving passively in flexible response to the finger action. This vibrato is smaller in width than the other types." (p. 40)
