For the production of voice we need 4 things:
1. Air pressure produced by the lungs to vibrate the vocal chords
2. Vocal chords that open and close creating vibrations in the air-flow
3. Resonance of the air vibrations in the vocal tract
4. Openings in the body like the mouth and the nose to let the produced sound out
If there is a problem with one or more of these requirements the voice quality will suffer.
When the vocal chords close more, there is more surface to vibrate or to produce sound. So
when they are closer together, the sound becomes louder, with a lower pitch, with more vibration.
After each vibration, the vocal chords close very fast, for a short moment. Air under the vocal
chords builds up pressure and when they re-open the vibrating air comes out, producing the
Male and female voice
The frequency of the male voice is around 120 Hz and of the average woman lies around 210
Hz. This means that the vocal chords will close 120 times and 210 times a second for the male
and female voice. If you have a job where speaking is important, they will close 30.000 times an hour.