The New Student's Reference Work/Voice

Voice is the sound produced by the movements or vibrations of the vocal cords in the larynx. The larynx is in the neck, between the trachea or windpipe and the pharynx, that part of the throat directly behind and below the mouth. The vocal cords are two elastic bands fastened across the larynx between which the air from the lungs passes out. The arrangement resembles two strips of india-rubber stretched across the mouth of a glass-tube, into which air is forced by a bellows, which would cause the edges of the rubber strips to vibrate with sufficient rapidity to produce a sound, the pitch depending upon the number of vibrations in a second. The first thing necessary to produce a sound is the expulsion or driving out of the air through the glottis or opening between the vocal cords; and the second necessary condition is that the cords should be close enough together and tight enough to vibrate rapidly. All the variations between high and low notes are produced by changes in the width of the opening and in the tension or tightness of the cords. If the cords are more than one tenth of an inch apart, there will be no sound. The pitch of the voice, depending upon the number of vibrations in a second, is determined by the length, size and tension of the cords. The pitch of the male voice is lower than that of the female voice, because the cords are longer. A boy's voice breaks and falls about an octave at the period of life when the cords lengthen; and in old age the voice changes, because the muscles which move the cords lose their elasticity. Hoarseness is caused by roughness or swelling of the cords. The ordinary range of the voice is two octaves, while the ear can perceive musical tones for 11 octaves. The quality of the voice depends upon the strength and elasticity of the vocal cords and also upon the shape of the passages of the ear, throat and mouth through which the sound passes, a slight difference in these respects causing the same varieties of tone etc. in the human voice as in a musical instrument. Voice differs from speech, which is the production of sounds to express ideas. Animals have voice without speech. In speech the tones produced by the voice are changed by the action of the organs of the throat and mouth, as the tongue, lips, teeth palate etc., into a large number of simple sounds, which, put together, form words. These vocal sounds are divided into vowels and consonants, the different combinations of which produce the hundreds of thousands of words which form the languages. See Human Physiology by Carpenter and Voice, Song, and Speech by Browne and Behnke.