Understanding the voice (1/4)
The voice production
The voice is produce by the vibration into the larynx of the air coming from the lungs, vibration which is modified by resonances in the mouth and in the nose.
The voice is therefore determined by three systems:
Singing well involves the use and control of these three systems.
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Air production
To have a powerful and stable voice, we must have a powerful and stable airflow. To do this, we must work on the muscles which are involves in this production, but also in the posture that would make the best use of the capacities of these muscles.
To breath out the air, we must begin by inspire it and fill the lungs. This is the role of the inspiring muscles the most important of which is thediaphragm. Then we contract the expiration muscles for blowing the air through the larynx. The inspiration and expiration muscles work in pairs and allow a fine control of the air flow. The inspiration muscles slow down the expiration muscles so that all the air is not blown at once. The control of the diaphragm is important both to inspire a large quantity of air and to control the flow during the singing.
When you are sitting or when we are stooped, our lungs can not be filled completely and therefore our ability to breathe is reduced. To sing well, we must stand and be in an upright position.
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The head position has also some influence, the chin, pulled up or down, can interfere with air flow. It also causes the tongue muscles to tighten, which alters the sound production.
The air vibration
The vibration of the air is carried out by the vocal cords, which are types of flanges flesh inside of the larynx. The precise mechanism is described in the diagram below.
When we inspires, the vocal cords are open and the air pass freely through the larynx.
When we speak or sing we contract the muscles of the vocal cords which close the passage of the air, the air pressure increase, the vocal cords are forced to open and a breath of air escape producing a sound, the air pressure decrease and the vocal cords close again. This cycle repeats at a frequency which depends on the tension in the vocal cords and the air pressure. It's just the same mechanism that when you whistle, except that in the latter case, it is the lips that makes the sound.
Understanding the voice (3/4)
Understanding the voice (2/4)
The voice mechanisms
The opening and closing of the vocal chords are done in two modes: the heavy mecanism (or mechanism I) and the light mechanism (or mechanism II).
The heavy mecanism is used mainly by men, it can produce sounds between 80 Hz and 400 Hz. In this mode of operation, arytenoid cartilages, which are at one end of the vocal cords, move at the same time as these.
The heavy mechanism
The light mechanism is more particularly used by women and children. In this mode, the vocal cords are more strained, and the arytenoid cartilages do not move at all. The frequencies produced this way are approximately between 300 Hz and 1500 Hz.
The light mechanism
These mechanisms are not restricted to one sex or another. Men can use the light mechanism and women the heavy mecanism. The most recent studies show that there is no other mode of production, it uses either one or the other, and there is no smooth transition between the two.
The transition between mechanisms
When a man start from a low-pitched note rising gradually to a high-pitched note (and the opposite for women, from high-pitched to low-pitched), one can hear a discontinuity at the time the singer change from a mechanism to the other.
It is possible to train for that passage to becomes inaudible, then we can produce a continuous note like a warning device.
The transition is not done at the same frequency for everybody. For non trained voices this transition is done generaly between 290 and 350 Hz for the men, and between 300 and 310 Hz for the women.
Singing vocabulary and mechanisms
One speak of "head voice" for the voice produced by the light mecanism by a woman. When it is by a man, one speak of "falsetto voice" (from an Italian word).
For the heavy mecanism used by men, one speak of "chest voice".
These terms were created at a time we did not know yet the exact mechanism of the production of the voice.
The other mechanisms
There are two other mechanisms less used than the two main, they are the "fry" and the "whistle".
The fry is a kind of moan produced in the very low pitch and made by relaxing the vocal cords with a low air pression. It is more easyly made by men.
The whistle is more easily produced by women in the very high pitch. The air passes forcefully in a narrow passage between the vocal cords which pratically do not vibrate. It is the turbulence of air that produces the sound.
The control of the pitch
The pitch of the voice depends on four parameters:
- the air pressure,
- the stretching of the vocal cords,
- the vocal muscles stiffness,
- the joining strength of the vocal cords.
The air pressure is controlled by all the breathing muscles: diaphragm, abdominal muscles, intercostal muscles, and to a lesser extent neck muscles.
The other parameters are controled by the larynx muscles: cricothyroid muscle, thyroarytenoid muscle, lateral cricoarytenoid muscle and posterior cricoarytenoid muscle. The effect of these muscles depends on the mechanism used.
The control of the pitch is therefore primarily a muscular control. His mastery is a question of training, as in athletic training.
The audio-phonatory loops
Singing well supposes hearing well. The deaf have trouble controlling their voices. Buildup of wax in the ear or some ear infections will disable the hearing of low-pitched sounds, other deafness may affect high-pitched sounds.
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The voice we produce reaches our ears using three ways:
The high-pitched sounds are poorly transmitted through the direct path, so that when you listen to your recorded voice, it is difficult to recognize it, it seems too high-pitched.
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In the long circuit, there is a feedback of the room that is variable depending on the type of materials used and its dimensions. Some rooms are more attractive than others, depending on whether the voice is properly returned or is lost in the distance.
In the internal listening, the voice reaches the ear through vibrations of the bones, tendons and muscles. The voice is distorted: the sounds do not spread the same way in air and in the body tissues.
All these internal and external sounds mix, varied in quality and shifted over time, it is an additional reason for not recognise his voice on a tape.
Singing in tune
Everybody can sing, with varying degrees of ease, but the singing out of tune can generally be corrected quite well. Singing in tune involves three steps: to hear, to remember, to reproduce. It is rare that the hearing or the memory is concerned. In general, sing out of tune comes from a lack of learning.
Generally, when we sing out of tune, we can hear that something is wrong and we search at random how to correct that. Canta responds to this research by showing exactly how to correct our voice. Canta creates a feedback loop which replaces the deficient audio-phonatory loop and allows to gradually strengthen it.
The regular repetition of these exercices with Canta will develop the internal representation of the right notes and also the efficiency of the command circuits of the muscles involved in the pitch control. It's like a bodybuilding equipment which would force you to make the right gesture to develop certain muscles, the repetition of these gestures will help you develop these muscles with maximum efficiency.
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The vibrato
The vibrato is a variation of frequency and amplitude of the voice around the note the singer aim at. The pitch deviation is around one quarter to a half-ton, with a frequency of 5 to 7 Hz.
It should not be confused with the trill, which is rapid alternation between two adjacent notes, nor with the trillo which is the chopped repetition the same note.
Vibrato and trills by Whitney Houston
The whispered voice does not have vibrato nor a forced voice produced without comfort and with muscle tension. The vibrato is involuntary. It is produced when there is a position of balance between two antagonistic muscles of the larynx thanks to a reflex loop. This is the same reflex mechanism that shook the knees of some sitting when they put their feet on the edge.
The vibrato is significantly amplified by a resonance effect of the laryngeal skeleton whose frequency is around 5 Hz.
To remove the vibrato of a voice is possible but requires energy and lowers the efficiency of the voice.
The vibrato is a natural phenomenon, neurologycally programmed. It can not be taught but is revealed when the rest of the vocal gesture is made under optimum conditions.
Understanding the voice (4/4)
The voice timbre
The sound produced by the vocal cords is formed, like any vibration, of a mixture of frequencies, called harmonics, which are multiple of a basis frequency called fundamental. The distribution of the magnitude of these frequencies is called spectrum in acoustic or timbre in music.
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Canta shows the lower part of the spectrum of the voice, in the region where lies the fundamental, between 80 and 1500 Hz.
The red line represents the position of the fundamental, the other bumps are the different harmonics.
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Our ear is able to detect not only the fundamental of a sound, but also recognize different spectrums.
 | The voice resonators
The spectrum of the sound produced by our vocal chords is changed by the resonances of the different harmonics in the cavities located between the vocal cords and the outside: the pharynx, the mouth and the nasal cavities. Depending on the form of these cavities, certain frequencies will be faded while others will be amplified and will be more audible. The areas where the harmonic frequencies are amplified are called formants.
The biggest changes in the spectrum are caused by the position of the tongue, the jaw and the opening of the mouth. One can alter the shape of the oral cavity and produce different vowels with the same pitch.
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The detection of the first formants allows us to distinguish between vowels and then allow us to speak (and to sing). What counts for understanding of speech, is the relative position of the formants and not so much their absolute value, thus it is possible to sing vowels at different pitch and to remain understandable.
In the diagram below, you can see how the tongue and the lips can alter the shape of the oral cavity and thus change the spectrum of the produced sound.
The vowels
The nasal vowels are produced by lowering the soft palate that causes a reduction of the high frequencies.
The consonants are not harmonic sounds, they are transients without fundamental frequency. They are produced by different modes of opening and closing of the mouth.
Generally we do not confuse two people saying the same vowel. This stems from the rest of the spectrum, including the highest part which is not involved in the detection of vowels, but which is fundamental for the voice timbre. The color of the voice is unique to each individual, it depends on its anatomy and how it articulates the words.
The singing formant
It is an area of resonance of the human voice located around 2800/3000 Hz for the men and 3000/3200 Hz for the women. This is the region where our ear is the most sensitive, while the instruments of classical music only produce low frequency in this area, allowing the voice going out over the orchestra.
The diphonic singing
It is a form of singing used in Central Asia in which one selects some harmonics that become so intense that it gives the impression of a second melody. We can test this approach by dividing the oral cavity with the tip of the tongue.
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