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What are vocal folds?

        Wikipedia article: Vocal cords

Vocal folds are small flaps inside the larynx (the lump inside your throat) that vibrate to produce sound with the help of airflow. The vocal folds have different "modes" (called registers) but in normal voice training you should focus on modal (M1)

  • The glottis is the opening between the vocal folds


From lukimon_client_handouts_-_copy.pdf — Upscaled with Waifu2x

What happens when you modify vocal fold mass?

When vocal fold mass is increased, more of the vocal folds move when producing voice.



Fred the Oyster / CC BY-SA


150px-vocal_fold_animated.gif 150px-vocal_fold_falsett_animated.gif

Reinhard / Public domain & Reinhard / Public domain

  • Lots of mass vs little mass moved

Why modify vocal fold mass?

There are two primary differences between male and female physiology:
  • Vocal Tract Length
    • The larynx, pharynx & the oral cavity expand under testosterone
    • Resonance is modified to "reverse" this for voice feminization
  • Vocal Fold Mass
    • Testosterone expands the vocal fold length:
      • From 12.5-17.5mm to 17-25mm
    • Alteration of the vocal fold mass reverses this effect
    • When reducing the mass, voice sounds thinner and smaller
      • Recreates female physiology

This is a vital part of voice feminization! 

Affects of testosterone

The length of vocal folds change as you enter puberty. However, if testosterone is present, irreversable changes occur:

  • The vocal folds grow in length (and become rounded)
  • The vocal fold epithelium thickens
  • (The thyroid also becomes more prominent)

While these changes are irreversable, they can be worked around with habit. Because the vocal folds grow in length, they become less tight (imagine people playing a game of tug of war and just walking towards each other) which means the voice sounds more "buzzy" If you're aiming for a feminine voice, you want to learn to stretch your vocal folds while phonating (this is called thin folds). If you're masculinizing your voice, (i'd assume) you want to learn to learn to stop stretching your vocal folds. 

How to modify vocal fold mass?

Vocal fold mass is controlled by 5 variables:

  • Airflow force (force of air)
    • How much strength is applied with the lungs to displace air
  • Fold Closure
    • Clenching or opening of vocal folds
    • Referred to as adduction: adding force, or abduction: aborting force
  • Configuration
    • Spectrum of thick-thin
    • Controlled by engaging or disengaging more or less of the vocal fold tissue

(less important)

  • Pitch
  • False fold behaviour

These elements are deeply connected, but can be controlled pseudo-independently. Control over all three gives greatest freedom, but control over configuration gives the greatest effect.


Personally, I (jo) like to learn one exercise and do it before speaking. For example, saying a voiceless /h/ before saying "Hi!" or saying "awwh". You can eventually learn the position without doing the exercise and "jump" to the correct configuration. Then all you gotta do is make this a proper habit! Good luck <3