THE human voice (German, Stimme; French, voix; Italian, voce) is an instrument of the same type as the oboe or bassoon. These instruments have what is known as a double-reed mouthpiece; and in similar fashion the throat is provided with two membranes called the vocal cords, which swing toward and away from each other when producing a tone, and let out successive air-puffs of the requisite number per second for the pitch of the note sung.
The lungs and the muscles controlling them supply the necessary air. When we breathe with an open throat, the air current is exhaled without impediment. But when the vocal cords are in action, closing the throat except for the release of air-puffs, the muscles controlling the lungs may be in definite action, forcing the air out if a tone of any volume is to be obtained.
The muscles governing the lungs act in three ways. The diaphragm, a broad flat-arched muscle at the base of the lungs, contracts downward to inhale air, and relaxes upward to let the air be exhaled, or even pushes upward in making a tone. The rib-muscles may expand the lungs by enlarging the chest circumference. Still another sort of inhalation may be made by lifting the chest and elongating the lungs upward by means of the shoulders. There is a great deal of discussion as to what is the best method of breathing for singers; but many of them are now agreed that an enlargement of the lower ribs, helped by a slight back-expansion and raising of the shoulder-blades, is the proper method of inhalation. The student may train his back in breathing by inhaling in a sitting position, leaning forward until the face almost touches the knees. After the inhalation, the burden of action in tone-producing is shifted to the diaphragm, which controls the tone best during exhalation. Breathing by the diaphragm is the most wholesome procedure in ordinary life; but the singer must train for special results.
The larynx, which may be felt as the Adam's-apple, is the