Hypo- & Hyper-Adducted Phonation
A brief video demonstration of gradually transitioning from a breathy (hypo-adducted) to a pressed (hyper-adducted) phonatory setup.
Overview
Here, we’ll explore the extremes of vocal fold configuration for phonation, from a very breathy, relaxed glottal closure (hypo-adducted phonation) to a very pressed, highly tense glottal configuration (hyper-adducted phonation).

Five Levels of Understanding

Introduction
When I was studying classical voice as an undergraduate music major, I was often frustrated that I could not make it through phrases without running out of air early. The most logical explanation I could think of at the time was that I was not engaging my breathing muscles adequately in order to release air more steadily. Looking back and listening to old recordings of myself, I now see that the real problem was my tendency to sing with a somewhat breathy sound. Think of the vibrating vocal folds as a valve for flowing air. If this valve is leaky, then the air will escape more quickly. Basically, it did not matter how much I trained my thoracic and abdominal musculature to maintain expansion and resist collapse while singing; if the vocal folds were not adequately sealed, then I would not be able to sing long phrases. As a teacher now, this is exactly why I spend far more time training the larynx than I do the breathing apparatus. If you are interested in learning more, check out the remainder of this page, where I will explain the physiological setup and results of singing through both relaxed (my old habit!) and firm vocal fold configurations. I will provide examples and teaching/practice techniques along the way.
Introductory Materials
Key Terms & Concepts
Glottis
The space between the vocal folds that serves as the primary valve for the respiratory system and phonation
Pronunciation:
Image Credit: “Slagter – Drawing Larynx and vocal cords – no labels” by Ron Slagter, license: CC BY-NC-SA
Hyper-Adducted Phonation
Complete but overly-muscularized closure of the vocal folds during phonation, resulting in a pressed tone quality.
Note: The term “hyperfunctional phonation” is often used in the literature, but isn’t favored here so as to not stigmatize non-classical vocal setups.
Pronunciation:
Hypo-Adducted Phonation
Incomplete closure of the vocal folds during phonation, resulting in a breathy tone quality.
Note: The term “hypofunctional phonation” is often used in the literature, but isn’t favored here so as to not stigmatize non-classical vocal setups.
Pronunciation:
Interarytenoid (IA)
An intrinsic muscle of the larynx and the secondary adductor of the vocal folds (completes posterior closure), composed of the transverse arytenoid and the oblique arytenoids.
See It: You can see the transverse and oblique arytenoids’ position here and see them in action here. Or click here to scroll down to the full video below.
Pronunciation:
Larynx
A cartillagenous structure that houses the vocal folds (sometimes called the “voice box”).
Pronunciation (frequently mispronounced):
3D Model:
Lateral Cricoarytenoid (LCA)
An intrinsic muscle of the larynx and the body of the vocal folds
See It: You can see its position here and see it in action here. Or click here to scroll down to the full video below.
Pronunciation:
Resonant Voice
A balance in vocal fold adduction for phonation, allowing for balanced airflow and air pressure.
Note: There are a number of different names for this, such as “balance phonation.” This kind of phonation is widely favored as the default in Western classical singing. It is possible and, in many styles, desirable to lean into a slighly hyper or hypo-adducted phonation for stylistic purposes.
Thyroarytenoid (TA)
An intrinsic muscle of the larynx and the body of the vocal folds
See It: You can see its position here and see it in action here. Or click here to scroll down to the full video below.
Pronunciation:


Postglottal Apperture in
Young AFAB Singers
Young AFAB (assigned female at birth) singers often phonate with a postglottal aperture (sometimes referred to as the “mutational chink”), which will cause breathiness in their sound. This is developmentally normal and typically resolves on its own by early adulthood as the interarytenoids gain more natural strength for complete vocal fold closure. No need to belabor trying to achieve perfect vocal clarity with these singers!
Anatomy & Physiology
For singers of all genres, a primary goal should be to create sounds that are efficient, repeatable, and aesthetically appropriate. Vocal pedagogy texts have long been geared toward classical singing, which calls for “balanced phonation” in order to be successful in an acoustic environment. This implies that the vocal folds are fully together (adducted via thyroarytenoid, lateral cricoarytenoid, and interarytenoid muscles) without the recruitment of excess squeezing forces from intrinsic or extrinsic laryngeal musculature. According to Titze and Verdolini Abbott in Vocology: The Science and Practice of Voice Habilitation, “resonant voice is regarded as neither pressed nor breathy.”¹ If we compare this to the Goldilocks story, resonant voice – which we prefer to the term “balanced phonation” – then, is “just right.”
Certain styles of singing may call for a less adducted (breathier) or more adducted (edgier) setup, which can work well provided that the singer is using amplification. For this page, we’ll keep things simple and assume that the singing teacher and singer’s goal is to find that resonant voice.
Regardless of genre considerations, this is still the most efficient baseline for one’s vocal technique, but singers can benefit from having the capacity to adjust the degree of vocal fold adduction for stylistic purposes.
¹ Titze and Verdolini Abbott, 286
Resonant voice is “the ideal mix of laryngeal adduction (somewhere between breathy and pressed) and ample reinforcement of oscillatory glottal airflow by the vocal tract.”
Hypo-Adducted Phonation
(Very Relaxed Glottal Closure)
Standard Definition
In The Diagnosis and Correction of Vocal Faults, James C. McKinney describes hypofunctional phonation as “the failure to demand enough appropriate activity of the laryngeal mechanism,” caused by “an inadequate or incomplete closure of the glottis–the vocal folds do not approximate properly” (McKinney, 82).
In an effort to destigmatize non-classical vocal setups, we prefer to use the term hypo-adducted phonation, as it does not immediately evoke a negative connotation.
On a scale of 1 to 7 for glottal closure, this would be determined a 1 or 2, meaning very relaxed closure (Davids and LaTour, 45). The TA, LCA, and IA are only partially contracted, resulting in a posterior glottal gap. Since air is then able to escape more quickly, this is what results in a less harmonically-rich, airier tone quality.
Descriptions
Breathy, weak, smoky, under-energized, excess airflow
Genre Considerations
Indie music often invites a breathier sound as an acceptable stylistic choice. If a singer is using amplification in order to be heard and desires this particular vocal color, breathiness is not usually an issue.
The teaching and practice techniques listed further down the page are useful for a singer who is experiencing breathiness but aims to have a more resonant sound.
Hyper-Adducted Phonation
(Very Firm Glottal Closure)
Standard Definition
On the other end of the spectrum, McKinney describes hyperfunctional phonation as “demanding too much from the laryngeal mechanism,” caused by “excessive tension in the vocal folds themselves; however, they often are abetted in their action by too much tension in other muscles of the larynx and surrounding areas” (McKinney, 87).
Similarly to our thoughts on the previous term, we prefer to say hyper-adducted phonation, whereby the TA, LCA, and IA are overly contracted.
On a scale of 1 to 7 for glottal closure, this would be determined a 6 or 7, meaning very firm closure (Davids and LaTour, 45).
Teachers of singing and singers need to be more wary of this as a habitual setup because of the potential risk for vocal fold lesions and muscle tension dysphonia from increased mechanical stress when prolonged. Since the glottis is tightly sealed, air pressure increases, resulting in a harmonically-rich, brassier tone quality. While this can be an exciting sound, it should be carefully monitored from an efficiency and repeatability point of view.
Descriptions
Tight, pressed, strained, strangled, edgy, overpressurized, insufficient airflow
Genre Considerations
The closed phase of the glottal cycle is often longer in post-1970 musical theatre styles as well as contemporary commercial music. That said, these genres are meant to be sung with amplification, so the singer does not need to vocalize with as much subglottal pressure (determined by air intake) in order to make an acceptable, efficient, and repeatable sound.
Although the degree of glottal closure requires more adductor muscle contraction than resonant voice, teachers of singing and singers should be advised that this setup works more efficiently when paired with less air intake, due to the marked increase in subglottal pressure.
The teaching and practice techniques listed below are useful for a singer who is experiencing pressed voice and aims to have a more resonant sound.
Demonstrations
Teaching & Practice
Hypo-Adducted Phonation
(Very Relaxed Glottal Closure)
These will help to energize the body and encourage a better glottal seal so that the vocal sound will be clearer and more resonant along with increasing one’s ability to sing longer phrases.
Sing more loudly
Glottal onsets
Isometric exercises (lifting an immovable object while singing, pulling hands apart at belly button level)
High-resistance semi-occluded vocal tract (SOVT) exercises (large-diameter straw in water, small-diameter straw, /v/ and /z/)
Vocalize on front vowels like /i/ and /e/
Hyper-Adducted Phonation
(Very Firm Glottal Closure)
These will help to release unnecessary muscle tension and encourage a sustainable, unpressed glottal seal so that the vocal sound will remain harmonically rich while allowing air to flow more freely. This is of utmost importance in preventing vocal fold swelling and lesions (nodules, polyps, cysts, etc.)
Sing more quietly
Breathy onsets
Low-resistance semi-occluded vocal tract (SOVT) exercises (nasals, lip trills, tongue trills)
High-resistance semi-occluded vocal tract (SOVT) exercises (large-diameter straw in water, small-diameter straw, /v/ and /z/)
Vocalize on back vowels like /a/ and /o/, and /u/
Under the Hood
Sources & Further Reading