The mode of phonation relates to three factors: breath pressure, airflow, and glottal resistance. The modes could be decided by the glottal resistance which equals the breath pressure by the airflow. The mode could be:

  • pressed phonation: high resistance; stronger high harmonics; "metallic", "overly bright",
  • breathy phonation: low resistance; weaker high harmonics; "airy", "fluty",
  • flow phonation: moderate resistance.

Different from the modes of CVT (Complete Vocal Technique), which is about the register and sound production mechanisms, including neutral, curbing, overdrive, and edge. The modes here is about phonation. It is more related to the sound, which is the results of different mechanisms, instead of the mechanisms itself.

The laryngeal register refers to the muscular adjustment of the vocal folds for pitch regulation, which is primarily controlled by:

  • the thyroarytenoids (TA): vocal fold shortening, thickening vocal fold muscles.
  • the cricothyroids (CT): vocal fold stretching, thinning muscles that lie partly outside the larynx.

Two laryngeal registers list here are:

  • chestier (shorter, thicker vocal folds), more and stronger high harmonics <-- the more complex pressure form <-- vertical phase difference <-- thicker vocal folds <-- TA,
  • headier (longer, thinner vocal folds), fewer and weaker high harmonics <-- more sinusoidal pressure wave <-- little to no vertical phase difference <-- thinner vocal folds <-- CT.

The chestier and headier register might correspond to the modal voice and falsetto voice register, respectively, in the four-register system together with the vocal fry register and the whistle register.

Here the word register should be carefully used, which is determined by three key elements:

  1. A register is composed of contiguous pitches;
  2. Pitches within any given register are produced in the same physiological manner;
  3. Pitches within any given register share the same basic timbre.

By the word register we mean a series of consecutive and homogeneous tones going from low to high, produced by the development of the same mechanical principle, and whose nature differs essentially from another series of tones, equally consecutive and homogeneous, produced by another mechanical principle (Garcia, 1847)