Bel canto from the 17th to the early 19th century
Bel canto singing from the 17th through the early 19th century was built primarily on the recognition that the intensity of vocal tone on a single note may be increased or diminished. The varying of this intensity was known as the messa di voce. There is, however, a difference between variation in intensity and variation in volume of vocal tone. The style depended on the technique of intensity; that is, tone was varied by increasing or decreasing the air pressure on the glottal lips and not by enlarging the oral chamber, which merely resulted in a larger tonal volume. The style was also based on the principle that the voice has two “tones,” a diapason tone produced when the larynx is in a relatively low position, and a flute tone when the larynx assumes a higher position. These distinctions, however, were largely obliterated when a broader style of singing was introduced by Richard Wagner and later composers.
Physical aspects of the technique of bel canto singing demanded a stance in which the chest was raised and the stomach drawn in; the raising of the soft palate together with a corresponding lowering of the larynx; and the drawing back of the chin with the effect of opening the throat. Correct breathing was above all essential, and the Italians went so far as to declare that “he who knows how to breathe can sing.” By a contraction of the upper abdominal muscles, control is achieved over the diaphragm, which thus enables the flow of air pressure from the lungs to be kept steady. This principle, which was the basis of singing in the 18th century, was later adopted by the Spanish tenor Manuel García, who declared that “the lungs are for tone emission, the glottis is for pitch, the oral cavity is for vowel and timbre, and the front of the mouth is for consonants.” The function of the diaphragm is to regulate the pressure of air, while the larynx, as a nozzle in a water spray, determines the nature of the flow.
With the muscles in appropriate position and the reserve of air under proper control, accented notes in singing are given their full value not as startling percussive notes but in the manner of an accented note produced by a violinist who prepares his effect by the proper placing of his bow. An exercise known as vibrazione enables the singer to control the voice at the larynx and, by attacking a note softly, to increase the volume by pressure of the larynx.
