Sound is vibrations, which propagate in elastic media, for example, in air or in water. Any object, if it is forced to vibrate, becomes the source of the sound*. The nature of birth sounds clearly you can imagine.
If you make a sharp displacement of the particles of an elastic medium in one place, then this place will increase the pressure. Thanks to the elastic relations particle pressure is transmitted to the neighboring particles. Those, in turn, affect the following, and the area of high pressure as it moves in an elastic medium. For the region of high pressure followed by a region of reduced pressure, and, thus, there is a series of alternating regions of compression and rarefaction propagating through the medium in the form of waves. Each particle of an elastic medium in this case will oscillate. This is a longitudinal wave.
The voice of man is also the sound vibrations of the air. Where do they come from?
In the respiratory system of the person. If the air passed through our bodies breathing freely, then we would not have uttered no sound. But in our respiratory system is such obstacles. A collection of organs that are involved in the formation of the voice call voice apparatus.
We can talk (and to shout, sing, whisper) only on the exhalation, when the air leaves the lungs through the mouth and nose. In our respiratory system is the area between the trachea and throat called the larynx. The larynx is a cartilaginous tube, covered inside the mucous membrane. Above the larynx is covered by the epiglottis, which consists of elastic cartilage and in front of the entrance to the larynx. The mucous membrane of the larynx has folds, protruding into the uterine cavity and containing ligaments and muscles. These folds are called the vocal folds (also called vocal cords). The crack in the larynx between the vocal cords is called voice crack. It is the vibration of the folds when the airflow through the glottis creates a sound wave, and thereby generates the voice.
When the silence of the glottis open wide, talking or singing - narrows.
The human larynx during inspiration and exhalation, followed by a speech (b):
1 - the epiglottis, 2 - vocal chords
Muscles of the larynx are able to change the position of its cartilage. The result can vary the width of the glottis and tension of the vocal cords. The dimensions of the vocal cords determines the type of voice that people with low voices folds longer and thicker, and higher short and thin.
In addition to the respiratory system and center sounds - larynx voice apparatus includes articulatory apparatus and resonators.
Articulation (from lat. articulo - "dismember") is the work of the organs of speech in the formation of sounds. Articulatory apparatus serves for the formation of articulate speech sounds**. In addition to the vocal folds to the articulatory apparatus include the tongue, lips, palate, throat, teeth.
The character of the sound depends on whether created noise when air passing through the vocal apparatus. The noise occurs when the air stream meets along the way additional obstacles - the organs of the mouth. If there is noise in the formation of sound does not happen, we are dealing with a vowel sound [a], [o], [y], [e], , [s]. If the voice joins noise, there is a consonant sound. Consonants, which consist of voice and noise called ringing (for example, [d], [C], [m], ). Consonants, which consist only of noise (for example, [t], [C], [f], [p]) called dumb. Vocal fold when the education of the deaf consonants do not fluctuate.
Moving the speech apparatus (tongue, lips) are called active, fixed - passive (upper lip, upper teeth, one or another part of the sky).
Active organ of speech all consonants are divided into lip and tongue. In a passive organ of speech all consonants are divided into dental, palatal-dental, medium-Palatine and rear-Palatine.
The resonator is a cavity resonant to occur in the glottis sound and giving him the strength and color (timbre). Resonance (from lat. resono - "sound in response", "respond") - the phenomenon of amplification of oscillations in the cavities under the influence of external vibrations of the same frequency.
Distinguish between the head and the chest cavity. Due to the upper resonators voice becomes bright, but at the expense of lower - strength, softness, fullness of sound. To the top of the head cavities are cavities lying above the vocal cords - nasal, maxillary and frontal sinuses. To the lower resonators includes the trachea, bronchi and lungs. The top and bottom to the roof immediately adjacent tubular cavity constituting it whole. Bottom podhorany tube enters the trachea and bronchi. Top Nagarjuna pipe enters the cavity oropharynx and forth in the oral and nasal cavity.
Head resonance is felt as a vibration in the head (teeth, crown). Chest resonance is felt as a vibration in my chest (trachea, bronchi).
the passage of sound waves through the resonators acquired characteristic for each person tone of voice. The voice is a unique individual as a person, which distinguish him from other people. As no two persons exactly alike each other, so no two are identical timbre of the voices. It happens that one may not recognize the face of a man, whom he had not seen for many years, but the characteristic elements of the voice of the person remain constant throughout life, and no bad habits or special exercises can't change it.
Speaking about the bodies that make up the vocal device, we can not forget the Central nervous system. Special speech centers of the brain to organize functions into a single, coherent process vukobratovi, which is a complex psychophysical act.
* Audible to human sounds are only those vibrations which are perceived by our hearing aid. Not all fluctuations in pH can be detected by the ear, but only those that are in the interval from 16 to 20,000 Hz. Sounds below the range of human audibility called inputvalue above - ultrasounds.
** The formation of sound voice called golosovanie, or panacea.