To administer successfully to the needs of adolescent singers, a teacher must have an understanding of basic phonation within the vocal instrument, particularly in relation to the way the voice divides into registers (that is, chest voice or head voice).

Intentionally, a deeply detailed, scientific explanation of registers is not presented here.  An attempt is made to explain a very complex operation in simple lay terms.  For a deeper, more discerning explanation, one may consult William Vennard’s book, Singing:  The Mechanism and the Technic*, particularly Chapter 4, or some other good book about the physiology of the voice.

In general, all singers (male, female, child, adolescent, and adult) have two usable registers.  There is a third in the extremely high area of the child and female voice called the whistle register and another in the extremely low area of the adolescent changed and adult male voice referred to as fry tones, but these are not very useful for singing.  Some teachers avoid using the term “register” altogether, particularly those who teach voice from a resonance point of view, because they want to discourage any implication that the voice is segmented.  Their desire is to train the voice so that it sounds consistent from top to bottom.  The use of the term “register” here should in no way discourage the attempt to reach that same goal with adolescent singers.  Some teachers use terms that imply three usable registers, such as “modal” (other terms used for the same are “full” or “normal”), “head,” and “falsetto” for the male; and “chest,” “middle,” and “head” for the female and boy treble.  For purposes of this explanation, one must think about the high, light register (falsetto in men and head voice in women and boy trebles) as opposed to the low, heavy register (normal, full, or modal in men and chest in women and boy trebles).  The head voice in men and the middle voice in women and boy trebles do not constitute a register (for the purpose of this explanation) but represent a mixture of the characteristics of the upper, lighter voice with those of the lower, heavier voice.  Henceforth, the two primary registers will be called head voice (upper, lighter) and chest voice (lower, heavier).

In lay terms, when students sing in chest voice, phonation occurs throughout most of the length of the vocal folds (really a set of complex muscular fibers called thyroarytenoids), which become shorter and thicker than when they are not active.  The glottis (the opening between the vocal folds) closes firmly and remains closed briefly during each vibration, so that air pressure builds up below and bursts out.  Each puff of air in each vibration opens the glottis in a rather explosive fashion.  This makes the chest voice suitable for low tones, which are comparatively loud and rich in harmonic partials.

In the head voice (falsetto in the changed male voice) the inner part (farthest from the edge) of the vocal folds (thyroarytenoid muscular fiber) is almost inactive.  The vocal ligaments that form the edge of the vocal folds are stretched and become quite thin.  In phonation, only the edges of the vocal folds (vocal ligaments) vibrate.  If the pitches are low, even though the opening is narrow, the entire glottis vibrates.  In the higher frequencies the glottis has time to vibrate only at the forward end.  The vocal instrument, operating in this fashion, exhudes a sound which is more flutelike in tone quality with fewer partials.

In most cases, singers are able to produce tones over a three-octave range.  (Notice that the statement says “produce tones”; they cannot sing well throughout the entire three octaves.)  The lower octave will be produced in the full voice (men) or chest voice (women and boy trebles), the middle octave may be produced in either voice, and the upper octave will be produced in the head voice (women and boy trebles) and falsetto (changed male voice).  Notice the illustration below.  It should be understood that when the term “octave” is used, depending on the voice, these pitches may be more or fewer than eight tones.

Although the above pitches may vary depending upon the voice type of the individual (tenor, bass or baritone), most males use only full voice from F (first ledger space below the bass clef) up to middle C.   They may use either full voice or falsetto from about middle C upward to G (second line treble clef) and falsetto exclusively from that G upward to G, one octave higher.  Most females, again depending upon the voice type (soprano, mezzo, or alto), use chest voice from F (fourth line, bass clef) up to D (directly above middle C).  They may use either chest or head phonation from that D up to A (second space, treble clef) and head phonation exclusively up to high G (fourth ledger line above the treble clef).  Notice that the lower “octave” in the male voice and the upper “octave” in the female and boy treble voices contain the most pitches, indicative of the type phonation that should be used as the predominant singing area of the vocal instrument.

With young singers, the teacher should attempt to keep the female in the head voice in the upper two “octaves,” using the chest voice only on the lowest tones of the literature.  Likewise, the teacher should attempt to keep the changing and changed male voices in the chest (normal or modal) area in the lower “octave” and most of the middle “octave.”  With the changing voices and the changed male voices, it is best to use literature that will keep them in the chest (normal) area most of the time.  The type phonation male trebles should use varies according to age.  Until ages eleven or twelve, young men should be trained to use head phonation predominantly.  However, if their singing experiences have been limited early in life and they begin singing around ages eleven, twelve, or older, it is a bit futile to train the head voice when in a year or two, as he enters the first phase of vocal mutation, the chest voice will emerge as the predominant portion of the voice to be used.

Please understand the importance of dealing correctly with the area with which head or chest phonation may be used.  Employing the wrong vocal phonation on these pitches can be very detrimental to proper vocal production and good health.