Kashu-do (歌手道): Squillo, a symbol for the mythology of vocal pedagogy

Few words are thrown about in vocal pedagogy as much as squillo. Like all the Italian catchwords that make up the large lexicon of terminology attributed to the Bel Canto Tradition, this word too is equivocal and only symbolizes concepts that are much more profound than its literal meaning.

Squillo: Suono acuto e brilliante. [A high-pitched and brilliant sound] (From the Italian Dictionary Online).
I have felt inspired to address this issue due to a very thought-provoking thread on NFCS (The New Forum for Classical Singers), mainly because the discussion reveals the level to which this word, and by extension vocal pedagogy as a whole, is unclear to us, the very people who practice it. Perhaps anyone profoundly invested in any discipline would say that the more one learns, the more one realizes how little s/he knows.  The difference in vocal pedagogy is that nothing can be taken as a given other than that ten pedagogues may have different opinions on a vocal issue, each passionately defending his/her view and rejecting the others, without any empirical basis. Even among the performing and fine arts, singing is singular in that regard.
When we consider Ballet or Figure Skating or even playing the cello or piano, enough research has been done on the biomechanics of skeletal musculature that a committed pedagogue could point to specific research that supports his/her approach. Indeed there are articles on carpal tunnel syndrome that speak to anatomy of the hand and its action relative to playing the piano or cello.  In singing, the intrinsic musculature of the larynx that drive vocal fold posturing and consequently vocal fold oscillation have not been studied, cannot be studied during the act of singing.  In fact this is the missing piece that scientists should work to find answers about.  
The great majority of vocal science is done relative to the study of speech and vocal disorders, in short observing and studying the vocal mechanism during average and sub-par function.  Operatic singing in the traditional sense requires a near-perfect balance between the intrinsic muscles that sets up the vocal folds into vibration in a specific morphology that yields a vibration pattern that addresses the most sensitive acoustic range of the human ear. In my opinion, this is specifically the acoustic patterns we see in the utterances of newborn babies before their expressions become educated. This specific acoustic pattern produces an intense sympathetic vibration in the aural cavities that the Old Italian masters of vocal pedagogy refer to as Squillo. The Italian masters realized that this “ringing” in the ear is produced by a voice that is operatically viable. It is this ringing that makes the voice more audible to the listener than other sounds in the immediate environment. This realization however does not tell us what makes the ringing or whether it is intrinsic to some voices and not others. This mystery is but one among many mysteries that drives the dark art of operatic singing. Dark, because many practitioners within our field are content to have it exist in the shadows of mythology rather than in the inexact world of partial knowledge that is its true nature!
The questions are the following:
  1. Do some voices produce squillo and others not? The answer seems obvious.  Yes! That part at least is obvious. No is the more complete answer.  The superficial answer is what we can observe. We can certifiably observe that certain voices produce the ringing in the voice that is synonymous with the kind of acoustic pattern that the human ear is most sensitive to, and that many other voices do not.  This could lead one to believe that squillo is a special occurrence in voices gifted by Providence to sing opera. Yet every crying baby produces the sound we experience as the ring in the voice. Babies crying can be heard over operatic divas and full orchestras. The logical answer is that all of us had squillo and some of us lost it as we grow up. Not every singer that has squillo in the voice has the necessary other components to become an opera singer (e.g. musical sensitivity, emotional expressivity and linguistic facility at least).  Operatic talent requires so many different skills. It is a complex talent. Those who are lazy about how to select operatic talent might take the easy way out by saying that those without squillo cannot develop it and therefore should not sing opera. That is a lie. Squillo is a prerequisite for singing opera viably and experience has shown me that anyone can develop it (or better said, recover it).

    Those with some acoustic science information will call it The Singer’s Formant. But that too is inadequate.  The Singer’s Formant is only the clustering of the upper three vowel formants and lies between 2500-3200 Hz. But this does not mean that the bandwidth of the singer’s formant is 700Hz.  It is much narrower than that. It is simply that the exact frequency of the SF varies between singers and indeed between voice types. In the high female voice (higher than D5), the SF falls too far between the harmonics to even have an effect on them. Yet the high soprano voice often exhibits squillo despite the fact that the SF does not apply.

  2. Is squillo the same as full glottal closure? Certainly not! But glottal closure is one component of the necessary fold posture that results in squillo. There must be enough fold-mass for the given tone to produce a tone rich in overtones.  Strength in the 2000-3000 Hz area is not enough for squillo.  A voice that has strength in this frequency range will be heard, but the kind of sound pressure that squillo provides includes strength in vowel formant areas as well. In other words, a voice may have strong high harmonics and still not have squillo. It can be heard but may sound tight and lacking in vibrancy.  The presence of strong lower harmonics in addition to the high ones guarantee that the glottal tone is produced in a way that allows for strong breath release during each glottal cycle. The high frequencies alone only show discouragement of the lower frequencies in favor of high ones. This can be accomplished with pressed voice. Therefore glottal closure alone is not enough to produce the kind of presence associated with a voice that is squillante.

  3. Can a voice be heard without squillo? Yes. It depends on the acoustic environment.  If the orchestra has a lot of doubling of the singer’s part, as is common in the music of Puccini and Wagner, then the singer needs a coordination that is close to what produces squillo in the voice. Even if the ring is not perceived, the sound pressure may be close enough for the singer to be heard, but that does not mean that any voice without squillo can be heard.  In fact my personal point of view is that the singer must become aware what a squillo feels like in the voices of other singers and should seek it in his/her voice. That should be the goal. And if the singer gets close most of the time, then the voice will have no problem being heard in the house. A well-produced opera voice should exhibit squillo throughout the voice most of the time, for that is what makes it possible to sing without a microphone when accompanied by challenging accompaniment that doubles the voice part.

  4. Is squillo tantamount to pressed voiced? Certainly not! Squillo cannot be produced in a pressed voice. But when squillo is equated with brightness or fold closure then certainly the perception of squillo could be that of pressing. Unfortunately this is the view of many teachers who promote loose phonation to avoid the pressing they associate with a voice with squillo. Those who have not been able to distinguish between the ringing in their ears and sheer loudness will fail to understand the subtleties.
In short squillo is the confirmation that the voice is at or near peak balance in terms of phonation, resonance and breath pressure. Quite often a singer has the correct laryngeal set up but the squillo is missing because the vocal tract shape (vowel) is incompatible with the glottal tone and suppresses certain harmonics that would contribute to squillo. Vowel modification is important as a refinement tool to achieve squillo. However, tracking formant resonances through vowel modification alone will not produce a squillo. The source tone must produce a rich spectrum of harmonics. This cannot happen when the fold mass is too little or when glottal closure is not efficient.
The tendency to oversimplify is what keeps vocal pedagogy in relative darkness and the complexity that lies below the simple Italian definition above is true of every Italian catch word that has come down as singer’s jargon. Voice teachers are a very opinionated bunch and to do the job well they have to be.  The problem lies only in stating an opinion as fact and shooting down anyone who disagrees for not understanding the principles of Bel Canto.  The term Bel Canto itself is thrown about as a shield against any suggestion to have a logical discussion about what we know and what we don’t know.
The voice teacher is in a very preacarious situation. S/he must make educated guesses because the vocal map is not complete. Scientists can only help us by giving us more information, but they are bound by the scientific process and thus in the absence of complete information they cannot make determinations. Singers cannot be so limited.  Despite incomplete information, we must deliver a product.  Yet the singer/voice teacher cannot fly totally blind.  If we use all the information the scientists provide, we can viably fill in the blanks.  Without using the information we do know we are likely to take the student on wild goose chase without any results to show for it.
The exercise that has kept applied vocal pedagogy in the dark is the following (often true in academia): two teachers with little empirical information will defend their diverging opinions with great passion, considering the other a quack. To keep the peace, they will agree in public that there is more than one way to skin a cat (i.e. that both approaches can work).  Often, neither approach is complete enough to yield consistent results.  It would have been prudent to consider a synthesis of the two approaches, which might indeed have produced a more complete regimen.  Unfortunately, on the surface, the two ideas seem opposite and neither teacher could conceive that an approach that seems so divergent from his/her own could actually work. 
When considering words like squillo and Bel Canto and appoggio, etc, it is important to realize that they are symbols for principles that touch on all three main functions (breath management, phonation and resonance).  The discussions that are sparked by these words provide much more complete information than any one opinion. A good teacher should always consider that what s/he dislikes most about a colleague’s approach might be the missing link that might make his/her approach more complete.

© 03/04/2010