Heavy and Light Mechanisms

The terms "heavy mechanism" and "light mechanism" are, in fact, two extreme manners to use the vocal cords. The heavy mechanism covers 2/3 of the lower tessitura, and because the light mechanism covers 2/3 of the high range, either mechanism can be employed for the middle third. It is a fundamental notion in our teaching and singing activities: the middle range of the singer can, by an appropriate training, extend and strengthen itself, reach balance between low and high overtones, and offer the total flexibility of the instrument.

Heavy Mechanism

 The heavy mechanism is sometimes called "chest voice" which creates a first misunderstanding: the chest voice is, according to us, the product of the heavy mechanism, not its cause. One of the characteristics of the heavy mechanism is the dominant action of the thyroarytenoid muscle (commonly called "vocalis muscle" in English) and the thickness of the cords which creates an intense and long closure of the glottis during the phonation. The accumulated pressure then opens the glottis almost like an explosion. The distance between both vocal cords is then rather important. The mechanism repeats itself then throughout the phonation in chest voice. The heavy mechanism is convenient for the low notes, precisely because of the wide amplitude of vibration of the cords.

Light Mechanism

The first remark concerning the heavy mechanism applies to the term "light mechanism". The characteristic function in "light" mode is, this time, the dominant action of the thyroarytenoid ligament. Vocal cords offer a weak resistance to the breath and the closure of the glottis is brief. The edges of vocal cords are thin.

Chest Voice

Term used to describe the vocal timbre produced by the vocalis muscle compared to the vocal ligament. Some people speak about vibratory sensations localized in the chest rather than in the head. The name is inaccurate but usually accepted notably in reference to the dark timbre, to the heavy mechanism, and to the low register or voice. One could speak of the pre-eminence of low overtones because of the low posture of the larynx. The chest voice can only be a part, the lowest, of the singer's voice. Indeed, it is physiologically impossible to sing "in chest voice" in the high extreme of one's tessitura.

The permanent use of the chest voice has consequences on the vocal health: "to sing in chest voice" on all the tessitura indicates simply that the singer did not discover or does not use other vocal mechanisms and pushes his chest voice as far as possible, often causing damages.

Head Voice

Term used to describe the vibratory sensations localized in the head rather than in the chest, or the high register. One can speak about the dominance of high overtones. For some professors, who often confuse head voice and falsetto, the head voice would be weaker in projection, in timbre, in power. These prefer the term "mixed or well-supportes mixed voice" to indicate the medium of the voice, or even the flexible singing. Anyways, well trained, head voice will match chest voice in timbre and power.

Mixed Voice

Combination of the chest and head voice, or low and high overtones. The notion of mixed voice implies a balance of its components. The larynx is lowered opening the pharynx and allowing the intervention of low overtones. High overtones are obtained by simultaneously lifting and widening or stretching the soft palate or velum. Some people add the term "supported" when the mixed voice is supported by the body implication. The term of "mixed voice" is often used in classical vocal interpretation, notably the art songs, and particularly as regards the French repertoire. The term "mezza voce" does not thus indicate the head voice register. It indicates a style, a way of singing. To accomplish mezza voce, it is not necessary to modify the mechanism of the full voice, but simply to reduce the intensity of the singing. One could also say that "mezza voce" allows to speak rather than to sing the words.

Falsetto

The treble range produced by most adult male singers. The voice commonly used by counter-tenors. When Falsetto is brought into use, only the thin edges seem to be used during the vibration; the internal mass of the vocalis muscles seem to be motionless. In time, this Falsetto, typically pale and fragile strengthens itself.

We then call it "reinforced or strengthened Falsetto". In the case of light lyric tenors, this reinforced Falsetto presents one very characteristic tone and a consistency which authorizes the use of this type of voice in the extreme notes of the tenor range.

Whistle Register or Superhead voice

A register of the female voice extending beyond the upper fifth. It is not necessary to linger there, its use not being frequent. The appellation "whistle" results from the description of vocal cords in this very high vocal area. Light lyric sopranos or dramatic coloraturas who practice the Cuperto may reach, quite as light lyric tenors, the upper fifth in a narrow and precise manner without tightening the throat with the use of false cords.

Vocal Fry

A register of the male voice which extends below the normal notes used in the singing or speaking voice. Quite as the whistle, its use is extremely rare and it is not indispensable to go further into details.

Full Voice

A voice which advantageously combines the qualities of the chest and the head voice. An intense voice, well-supported by the body. Caruso considered that his full voice was his natural vocal capacity.