Onset can be defined as the manner in which a vocal tone is initiated.  The initiation of vocal tone determines the quality of the sound, and thus is of primary importance to us as singers and teachers.  I would like to discuss the various types of onset here, and to make a case for the much-maligned coup de glotte, (or coup de la glotte) which can be a valuable tool when used correctly.

“Onset” for this discussion refers to vowel-initiated words; consonants have properties that affect onset as well, but are outside the realm of this discussion.

Vocal tone onset can be divided into three groups:  1) Aspirated (too much airflow), 2) Hard Attack (squeezed or over-compressed) and 3) Balanced/Coordinated Onset (a healthy approach that encourages balance between vocal folds and sub-glottal air pressure).

When we breathe, the vocal folds, attached behind the thyroid cartilage, are open in a “V” toward the back of the throat.  Before phonation can begin, the vocal folds must be approximated (brought to midline) by the gliding action of the arytenoid cartilages and adductor muscles (lateral cricoarytenoid and inter-arytenoid muscles), to which the folds are attached at the rear.  Once the folds are lined up, they can now react to the column of air rising from below.

The three varieties of onset result from differences in degrees of vocal fold positioning.


Excessive airflow before sound initiation is indicative of the aspirated onset, and is caused by an incomplete approximation of the vocal folds. With incomplete vocal fold approximation, the glottis (space between the folds) is too large, there is a lack of firm glottal closure upon initiation of sound, excessive airflow occurs, and the resulting sound is breathy. This type of onset results in a low closed quotient and inefficient vocal production, with a lack of higher harmonics.  To experience the aspirated onset, say the word  hhhhhhhhhhhhhhhhhhhhhhhhhhheeeeeee.


The hard attack (what I call “too much of a good thing”) is a result of pressed phonation- of over-compressing the folds to initiate sound. Coughing or grunting are examples of this type of “overkill” onset, which creates a build up of sub-glottal air pressure before sound is released in a “plosive” or explosion. Excessive air pressure, when released, is traumatic to the delicate tissues of the vocal folds.


The most important fundamental technique in singing is that of a clean onset to initiate vocal sound.  This occurs with a correct positioning of the vocal folds, even  before beginning a sound; this is known as pre-phonatory tuning. Correct alignment of the vocal folds before phonation begins efficiently balances  subglottal air pressure, resulting in an efficiently produced sound. A balanced or coordinated onset occurs when the vocal folds have been approximated (or brought to midline) and there is neither too much nor too little compression in the initiation of the sound.

The question of how to achieve a balanced or coordinated onset is answered by considering the degree of vocal error or dysfunction presented.  If a student is vocalizing with pressed phonation, obviously they need more release. The remedy can be found in the relaxing action of the aspirated onset (in other words, H, SH, F consonants) with the ultimate goal of  moving toward other less aspirated  consonants such as M and N in order to  eventually achieve a balanced onset.

However for the plethora of breathy students at the other end of the spectrum who, as Richard Miller puts it “remain physically somewhat uninvolved during singing…breathiness and physical detachment characterize the vocal sound.  It may then be wise to introduce the slight glottal attack so that excess breath is eliminated”.   (Richard Miller, The Structure of Singing Schirmer, 1986).

I am in total agreement with Mr. Miller on this point.  I can’t think of a tool or technique that creates better vocal fold adduction than simply speaking the vowel as we say it in speech.  Try saying “UH-OH”, “I Eat An Apple”, or simply “MM-MM”.  With every initiation of those words you are creating balanced, coordinated onset, (coup de glotte) and the resulting vocal tone is clear.  Now say “Hi Heat Han Happle” to experience the lack of effective onset created without the light coup de glotte.   (Perhaps a better term could be introduced for this function.  I use the phrase “adducted onset”)

I maintain that doing vocalises using vowels with a gentle or light coup de glotte (adducted onset) are often more effective than exercises using various types of consonant initiation.

A word of caution here:  Like any technique, the coup de glotte  could be overused, done too loudly, or performed with too much force. If done too enthusiastically the exercise can become potentially harmful because of “glottic shock”.  Glottic shock occurs when the folds are compressed too tightly together, allowing too much subglottal pressure to build; subsequently the folds are forced open by an explosion of air.  Any tool used to excess can become harmful, and this is no exception.

However, the pedagogues who insist that all coup de glotte is harmful are, I believe, throwing the baby out with the bath water.  All coup de glotte is not alike, the variances being those of degree.  A gentle or light adduction of the vocal folds at the initiation of vowel sounds is inherent in spoken language and can, I believe, be used effectively in teaching singing, particularly when working with breathy voices.  Clean initiation with a light but firm glottal onset encourages the folds to subsequently maintain resistance against the air coming up from below the glottis, thus creating clarity of tone during sustained pitches.  This firm resistance is what is known as “appoggia in gola” or leaning on the larynx.

David Jones, a respected teacher and author who writes a terrific blog about voice teaching ( calls this the “perfect attack”.  Allan Lundquist refers to the process as “clicking the cords”, indicating a gentle and light action rather than a forceful one.


The coup de glotte  technique was taught in the Italian schools from 1600 to the late 1800’s, as part of the bel canto method.  Manuel Garcia (1805-1906), a revered pedagogue and voice teacher of many well known opera stars, who is credited with the development of a dental-type mirror (a precursor to the laryngoscope) that for the first time allowed vocal scientists to view a singer’s vocal folds in action, was said to have made coup de glotte a basis for his vocal instruction.

The term coup de glotte has since been misunderstood and misinterpreted, perhaps because of a lack of understanding of Manuel Garcia’s intentions, along with a too-literal interpretation of the word “coup”. The term coup de glotte or coup de la glotte itself is unfortunate and not accurately representative of the light adduction of the vocal folds created by speaking vowel sounds at a moderate volume.

The French word “coup”, correctly interpreted, does not mean shock or blow, but simply “swift”.  Garcia maintained that coup de glotte simply referred to “the neat articulation of the glottis that gives a precise and clean start to the sound…the lightness of movement is considerably facilitated if tried with the mouth shut” (Manuel Garcia Traite Complet de l’Art du Chant, London 1870’s). To experience this, try saying MM-MM-MM with your lips closed. The light adduction of the vocal folds upon the initiation of sound is what Garcia was referring to.


To remedy breathy vocal production, I have found success in exercises using various vowel sounds to “set- up” a sustained note.  For example on a single pitch I might have them sing [e]- [e]- [e] sustaining the third pitch.  (That is IPA for AY- AY- AAAAAAAAAAAAAYYYYYYYY). (By the way, for those who are interested, the correct representation of the coup de glotte onset in IPA is [ʔ]).

From these “adducted onset” exercises as I call them, I like to eventually progress to staccato exercises that encourage the “silent H”.  For these silent H staccato exercises, on an EE [i]vowel for example, the onset is not HHHHH [i]  and not  a glottal stop initiated  [ʔ] [i] but somewhere in between.

Adducted onset coup de glotte exercises can be a valuable beginning tool for breathy singers in creating vocal fold approximation; the gentle or light coup de glotte is very effective in initiating clear vocal tone and in helping the singer maintain clarity and increased resonance throughout subsequent sustained notes.  However, like all good tools, it should be eliminated in vocalizing as soon as the student is able to initiate and maintain an efficient and clear vocal tone without assistance, and of course should be used judiciously.

My motto is always “just enough, but not too much!”



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