· Julieta Pizarro

The Dual Laryngeal Valve System and Its Application to Singing

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The following model describes a functional interpretation of the respiratory-laryngeal system as a regulation mechanism based on two complementary valves. This approach allows us to understand the relationship between air pressure, muscular activity, and sound from an integrated body perspective, where the larynx not only serves a phonatory function but also acts as a dynamic controller of airflow in coordination with breathing and posture.

General concept

The larynx can be functionally understood as a dual valve system that regulates the relationship between air pressure and the body’s muscular activity.

Every valve works against a pressure and fulfills a control function.

Exhalation valve: ventricular bands (false vocal cords)

  • Located above the vocal folds (vocal cords).
  • They tend to close in response to overpressure from the lungs.
  • Associated with the body’s strength and stability.
  • If overactivated, they can generate rigidity and tension when singing.

Inhalation valve: Vocal folds (Vocal cords)

  • Located below the ventricular bands.
  • Neurologically connected to the diaphragm and the inspiratory muscles.
  • Their activity promotes low pressure generation in the thorax (lungs).
  • They allow greater openness, flexibility, and vocal coordination.

Overpressure function

When the exhalation valve (ventricular bands) closes and the expiratory muscles (abdominals and internal intercostals) are activated:

  • Pressure inside the thorax increases.
  • Air pushes against the closed valve.
  • The thorax stiffens.
  • The vocal tract tends to narrow.
  • The vocal cords also tend to close as functional reinforcement.

This function is necessary for:

  • Defecation.
  • Childbirth.
  • Trunk stabilization.
  • Striking.
  • Pushing.
  • Running.
  • Producing centrifugal forces (outward).

However, this muscular organization hinders free and differentiated singing.

Low pressure function

When the inhalation valve (vocal folds) closes and the inspiratory muscles are activated:

  • Thoracic volume increases.
  • Internal pressure decreases.
  • A centripetal force (inward) is generated.
  • The thorax remains flexible.
  • The vocal tract expands both longitudinally and transversally.
  • The ventricular bands remain open.

This function favors:

  • Climbing.
  • Pulling.
  • Suspending the body.
  • Jumping.
  • Traction movements.

It also favors:

  • Lower subglottic pressure.
  • Greater laryngeal freedom.
  • Better resonance.
  • Greater functional differentiation of the vocal cords.

Neutral position

When both valves remain open:

  • Internal and external pressure equalize.
  • There is no airflow.
  • No predominant centripetal or centrifugal forces exist.

This can be considered an equilibrium position or “zero position.”

Breathing

During normal breathing:

  • Both valves must remain open.
  • Air flows in and out freely.

From a functional perspective, respiratory regulation depends not only on the diaphragm and the rib cage, but also on the coordination between both laryngeal valves.

Application to singing

”Onset” (beginning of phonation)

At the end of a functional inhalation:

  • The vocal cords exhibit a reflex tendency to close.
  • If this reflex is slightly interrupted before complete closure, air pressure sets the vocal cords into vibration.
  • In this way, a reflex and efficient vocal onset is produced.

Therefore:

The quality of the inhalation determines the quality of the onset, and the quality of the onset influences the overall quality of the voice.

Inspiratory tendency (diaphragmatic support)

During phonation:

  • Inspiratory activity must remain functionally dominant.
  • This keeps the vocal tract open.
  • It favors differentiation of the vocal cords.
  • It allows more precise regulation of pitch, intensity, and quality.

This functional organization is called:

Inspiratory tendency (or “diaphragmatic support” in more traditional terminology).

Sound termination

At the end of phonation:

  • If the overpressure function dominates, the vocal tract tends to close.
  • If the low pressure function dominates, the tract can remain open.

Sound termination becomes gradual rather than abrupt.

Hierarchical principle of the system

The vocal cords are autonomous and constantly modify and regulate:

  • Their closure (sound quality)
  • Their vibrating mass (volume/intensity)
  • Their tension (pitch/frequency)

These changes occur extremely rapidly during singing.

Therefore:

  • The respiratory system must continuously adapt to the needs of the vocal cords.
  • Respiratory regulation must respond reflexively to laryngeal activity.

Fundamental principle

The system is adaptable and hierarchical:

Breathing must be organized according to the needs of the vocal cords, not the other way around.

This model proposes an integrated vision of phonation and breathing, where the coordination between air pressure, respiratory musculature, and laryngeal dynamics constitutes a hierarchical functional system: the requirements of the vocal cords “direct” the system. Understanding these interactions allows us to approach singing not only as an acoustic phenomenon, but as a global body organization oriented toward efficiency, flexibility, and real-time adaptation of the vocal system.

Source: “Functional Voice Education, Rabine Method. First national conference led by Eugene Rabine and Renata Parussel.”