The gap between the vocal folds is called the glottis (rima glottidis) called. The rear ends of the vocal folds with the two legs connected cup cracking, which is the position of the vocal folds in relation to influence each other. When breathing, the vocal folds wide open (abduction), causing the glottis a typical triangular shape (see picture on the right). The voice is the muscle tension and thickness of the vocal folds change. Together with cricothyreoideus Loki Link Builder musculus, also the length and tension of the vocal folds changes, creates a mechanism to accurately control the volume and pitch of the human voice is controlled.
If during exhalation the vocal folds are tense, produced at the vocal folds increasing air pressure. When this reaches, they are pushed open and take the pressure temporarily, causing the vocal folds tightened quickly close again. Because of the pressure, closing it again, after which the process is repeated (the Bernoulli effect). The resulting vibration of the vocal folds is transferred to the passing air flow. The stronger the vocal folds are stretched, the higher the vibration frequency is higher and the pitch of the voice.
A male voice has a pitch of around 110 Hz, a female voice around 220 Hz and a child's voice around 300 Hz. This applies to Europeans, Japanese and other Asians have much higher average ratings.
The longer the vocal folds, the lower the voice sounds. The length of the vocal folds are generally proportional to the size of the larynx, which is why at the sudden increase of the larynx in boys in the age of puberty the voice is suddenly much lower, and they are disclosed in the throat.