WHEN A SINGER IS AFFLICTED with a too fast or too slow vibrato rate, does physiological hard wiring condemn him to that condition for life, or can he change it over time? In search of the answer to that question, Neisha Carter, a graduate student in the Speech Pathology program at Brigham Young University, under the direction of Dr. Christopher Dromey, her faculty mentor in her department, and in conjunction with Dr. J. Arden Hopkin, a professor in the School of Music, prepared a controlled study leading to her thesis, "Volitional Changes to Vocal Vibrato in Accomplished Singers" (2001). The study systematically investigated an informal experiment drawn from the undergraduate voice pedagogy course at BYU.
At the end of the unit on vibrato in the voice pedagogy class, the professor requests volunteers from the class to participate in an informal experiment. A student with a fast vibrato joins a singer with slow vibrato. In turn, these two students attempt to match each other's vibrato: one singer sustains a tone in a comfortable range and the other joins in after a moment, seeking to match the other student's vibrato. Class members are always impressed that the faster vibrato slows down and the slower vibrato speeds up during the experiment. Students customarily explain that they adjust their vibrato by adjusting placement and breath energy: the fast vibrato slows as placement moves back and as breath pressure diminishes; the slow vibrato speeds up as placement moves more forward and the breath pressure increases. Interestingly, in every repetition of the experiment, students report matching the tone quality of the other student as a means of matching vibrato: as the brighter voice becomes darker and the production heavier, the vibrato slows; the naturally dark voice brightens and lightens to speed up the vibrato. This informal experiment prompted the study leading to the thesis.
A thorough survey of existing literature on the subject gave meaningful context to the study and its results.
REVIEW OF LITERATURE
Definitions of Vibrato
A variety of definitions by researchers has contributed to the description of vibrato. Lebon viewed vibrato as a characteristic of a tone quality that adds vibrancy and richness, suggesting that vibrato that calls attention to itself or is obtrusive becomes a negative attribute.1 Large and Iwata found that vibrato added warmth and excitement to the tone.2
Carl Seashore was the first to study vibrato extensively. Cited to this day, his definition states: "A good vibrato is a pulsation of pitch, usually accompanied with synchronous pulsations of loudness and timbre, of such extent and rate as to give a pleasing flexibility, tenderness, and richness to the tones."3 Pfautsch described vibrato as "a slight and rapid fluctuation between two pitches in producing the singing voice."4 Callaghan explained the movement of vibrato to have a wavelike form when describing vibrato as "an undulation of the fundamental frequency."5 Pfautsch found the following characteristics in all vibratos and tone productions:
(1) There will be two pitches involved, (2) there will be variance in the two pitches involved, (3) there will be variance in the width between the two pitches involved, (4) there will be differences in the speed at which these two pitches are sung, and (5) one of the two pitches will dominate either by volume, by duration, or by both volume and duration.6
In the above description, Pfautsch described vibrato in simplistic terms that enabled the inexperienced singer to understand the phenomenon of vibrato.
Although the above distinctions are present during vibrato, the use of vibrato is viewed to be both an advantage and a disadvantage to the singing voice. Metfessel characterized vibrato as "a mannerism which soon becomes wearisome; a drawback and a sin which should be nipped in the bud; a disagreeable fault to be condemned, a dangerous vice to be shunned, a vicious wavering used by inferior talent, and a vulgarity. …