Vocal frequency

The voice has various attributes; these are chiefly frequency, harmonic structure, and intensity. The immediate result of vocal cord vibration is the fundamental tone of the voice, which determines its pitch. In physical terms, the frequency of vibration as the foremost vocal attribute corresponds to the number of air puffs per second, counted as cycles per second (cps or Hz). This frequency is determined by both stable and variable factors. The stable determinants of the individual voice range depend on the laryngeal dimensions as related to sex, age, and body type. The smaller a larynx, the higher its pitch range. Within this individually fixed range, variables that influence the pitch of a given phonation include: tension of the cord, force of glottal closure indicated by the glottal resistance, and expiratory air pressure. Growing tension of the cricothyroid muscle (as the external vocal cord tensor) increases the vocal pitch, and vice-versa. Increased glottal closure and expiratory effort add to this tensing effect under certain circumstances. For example, 100 vibrations per second produce a low chest tone of a low male voice, while 1,000 are close to the “high C” of a female soprano. An average vocal range normally encompasses two musical octaves (e.g., 100 to 400 vibrations per second); trained singers may reach three or more octaves.

Voice types

Musical practice for centuries has recognized six basic voice types: bass, baritone, and tenor in the male, in contrast to contralto, mezzo-soprano, and soprano in the female. Sex, therefore, is one of the first determinants of voice type in the two categories. Body type and general physical constitution represent the second determinant of the individual voice type because the laryngeal dimensions vary in fairly strict conformity to whether the body type is large or husky or frail or small. A tall, athletic male usually has a large, spacious larynx. Repeated observations show that short, dainty females tend to have a small and delicately built larynx. The intermediate voice types of the male baritone and the female mezzo-soprano usually represent the corresponding intermediate body types. The art of singing recognizes additional subdivisions. The voice of a basso profundo is extremely low and heavy. The lyric tenor possesses a high, light, and flexible voice. Still higher and lighter is the counter tenor (as used in singing oratorios) who is the male counterpart of the highest female voice found in the extra high and light coloratura soprano. The dramatic voices employed in the Wagnerian operas represent intermediate forms between a male tenor (or high baritone) and a heroically masculine body type. The female dramatic soprano is usually heavily built; her strong mezzo-soprano voice can produce the high soprano tones.

The registers are related to voice types. As a general rule, the low voices possess a large range of chest voice with a much smaller range of head voice. The reverse holds for the high voice types, while baritone and mezzo-soprano assume an intermediate position. In the normal individual and the well-trained singer in particular, the midvoice encompasses one musical octave. As a further rule of thumb, the traditional and optimal transition tones follow a fairly stable and general pattern.The three female voice types usually show the first transition from chest to midvoice at the tones d¹, e¹, and f¹, above middle c¹, respectively. The second transition between midvoice and head register in the three female voice types is almost precisely one octave higher. An extra-low contralto voice may prefer to shift the two transitions at slightly lower frequencies, whereas a very high coloratura soprano may prefer the two shifts a semitone (halftone) higher. The two transition tones of the three male voice types are situated almost precisely one octave lower than the respective six female transition tones. It should not be overlooked that the specific features in male voices sound approximately one octave lower than in the female voices of corresponding type. This octave phenomenon stems from the larger dimension of the adult male larynx. (The musical custom of writing the tenor part on the soprano stave in contrast to the correct notation of bass and baritone in the bass clef is a misleading tradition that derives from an old custom of four-part writing, for the tenor always sounds one octave lower than the soprano.)

Vocal ranges

The individual ranges of the singing voice extend from about 80 cycles per second in the low bass to about 1,050 cycles per second in the “high C” of the soprano (all values are approximated). The lowest note of serious musical literature is a low B-flat with 58 cycles per second, used in bars 473, 475, 477, and 632 of the bass voice of the chorus in the fifth movement of Gustave Mahler’s Symphony No. 2 (Resurrection). The highest is a high f³ with almost 1,400 cycles per second sung by the Queen of the Night in Mozart’s Magic Flute. Exceptionally high soprano tones are no longer sung with vocal cord vibration but are produced in the flageolet (or whistle) register simply by whistling through the narrow elliptical slit between the overtensed and motionless vocal cords. When citing the exceptional vocalistic feats of singers from the classical bel canto era, it should not be overlooked that musical pitch has been rising markedly since those days. Concert pitch is presently standardized at 440 cycles per second for the international tuning tone a¹. In the last half of the 18th century, the reference tone was at least one semitone lower.