Closed vocal folds and narrow larynx

The operatic voice as a brass instrument

Constriction is a rather dirty word in the singing world. It brings to mind all kinds of negative sounds and images: the strained, shrill high note of a disconnected soprano, the choking of the struggling tenor, the swallowed tongue of the hoarse bass- baritone or the gripped throat of the mezzo battling to retain her dark colored middle voice against rising tension. These are all very common examples of dysfunctional singing and should obviously be avoided by the ambitious singer. However, at the most fundamental level, great operatic singing is entirely based on a degree of constriction: the intense phonation of strongly adducted vocal folds and the narrowing of the laryngeal opening.

Somewhat counterintuitively, the most free, easy and flowing sounds are best enabled by closed vocal folds. If the folds are not vibrating when resisting moving air, no sound is being made. There is no other sound-maker in the vocal tract.  Every single voiced sound a singer utters derives intially from the vocal folds. The colors and acoustical enhancements made possible by shaping the vocal tract are themselves secondary vibrations (formants) set into motion by the phonation itself, regardless of how this may feel subjectively. No matter how well the vocal tract is shaped, if the source vibration from the vocal folds is weak, no amount of tweaking will result in a high quality sound.

The voice as a trumpet

To help illustrate this point, I would like you to imagine a brass instrument. A trumpet player, for example, pressurizes air inside the body, which is then resisted by the embouchure formed by the lips. The lips will vibrate as very small puffs of air break through the embouchure. The initial sound is not created by the air passing through the instrument from the player’s lungs, but by the vibration of the player’s lips. This is a fairly good representation of how phonation works. All trumpeters are well-aware that religiously training the strength of the embouchure is paramount for successful performance.

The strength of a singer’s phonation is just as important, hence the popularity of glottal exercises in historical singing schools. The traditional glottal attack was most famously described by Manuel Garica II as the “coup de glotte”. Garcia’s “coup de glotte” is often misrepresented; it is simply the commencement of phonation with an already closed glottis. People do this in speech hundreds of times every day; virtually every word beginning with a vowel in the English language, for example, is usually pronounced with a kind of “coup de glotte”. Equally, try saying the Italian word “ecco” without an intially closed glottis and you will find it comes out as “hecco”. The “coup de glotte” is to be strongly distinguished from the destructively violent slamming together of vocal folds to attack a tone from an open glottal position. It also does not require destructively high amounts of breath pressure, as is sometimes assumed.

Garcia was not doing anything radical with his exercises; he was mostly describing what had been important training tools for centuries while also attempting to find a scientific reason as to why these things worked. “Si canta come si parla” (one sings as one speaks) had been an adage in singing since the time of the castrati. If we speak with a closed glottal attack, we must therefore also endeavor to sing with one, and not with a defective, airy tone.

The aryepiglottic muscles as the mouthpiece of the trumpet

For another important example of functionally necessary constriction, we return to the example of the trumpeter. Naturally, the buzzing of the lips alone will not yield a great sound. Likewise, neither will intense phonation in isolation. In the case of the trumpeter, the lips connect to the mouthpiece; a tube with a flared opening, culminating in a narrow exit. Imagine now if the player was to simply blow rapidly into the mouthpiece with no embouchure to resist the airflow. Some sort of strange, airy sound will emerge from the instrument, but I can guarantee it will not be the full, resonant tone we expect from a professional trumpeter. That is why the trumpet is not played in this way. Yet, frequently, singers attempt acoustic performances with an analogous approach.

Put simply, the air contained within the constricted space of the mouthpiece vibrates sympathetically with the source vibration from the lips. The purpose of this is to harness and selectively enhance the harmonics of the original vibration.

In the vocal tract, the aryepiglottic muscles provide this same function. These muscles form a sphincter controlling the opening of the larynx. When we swallow, they totally seal the larynx so that nothing touches the delicate vocal folds. During singing or speech, they are able to narrow the space above the vocal folds to provide strong acoustic enhancement and, as a consequence, far greater efficiency. The narrowing of the aryepiglotticus is, in my opinion, necessary to achieve important traditional ideals: the related concepts of “voce chiusa” (closed voice), a sound that is “raccolto” (gathered) and the famous “voce squillante” (ringing voice). Research indicates that there is a strong correlation between ringing tones and this kind of constriction.

Literal constriction felt as subjective ease

It is important to note that a singer will not necessarily experience the closure of the vocal folds or the narrowing of the aryepiglottic muscles as subjective “constriction”; when everything is well set up, they will typically just experience an easier flow and more effortless resonance. Nonetheless, it is, quite literally, a greater degree of highly specific constriction that enables this mode. Of course, this constriction can and should exist in the context of a low larynx and an open pharynx.

Conclusion

Appropriate closure of the vocal folds and narrowing of the larynx has always been an enormously important part of classical singing. They are vital components for all singers wishing to develop acoustically exciting voices. Great singing is charactised by harmonically rich, multifaceted sounds that move us on some deep, instictive level. In order to achieve the acoustical set up necessary for this complex effect, some parts of the vocal tract must be hugely open and spacious, and other parts rather closed, just as in speech. The source vibration must also be emanating powerfully from strongly adducted vocal folds. When the whole vocal tract is spread open or squeezed shut, this complexity is impossible to achieve. When you sing with this kind of complex sound and couple it with geniune expression, you will hold any audience in the palm of your hand.