2.2 Intonation in singing voice

Vocal sound as an acoustic phenomenon.

The acoustics consider as sound waves of pressure that propagate through compressible media. The sound of the human voice is the vibration of the air particles that propagate as waves of condensation and rarefaction. It is like concentric waves that appear on the water surface because of a stone thrown in there.

When a person speaks or sings, his voice not only passes through the airways into outer space, but also propagates through the inner soft tissues of the body, causing the sense of vibration in different areas of the singers body, especially in the chest and the head.

The sound waves of human voice are generated in the larynx as a result of vibration of vocal folds and then spread in concentric circles all around the tissues surrounding the larynx. They only open partially into the outer space through the mouth. Only 1/50 of them come to the ear of the listener.

The airways of voice box are covered with soft mucosa. During the phonation singers should make their tissues harder to enhance the sound of their voices. To address this problem while adjusting the vocal placement, following techniques exist:

- Disclosure of the nose wings (as if smelling pleasant odors);

- Feeling of the soft palate like a cupola, while yawning;

- Lowering of the tongue root vertically down around with the larynx, like you do when pronouncing an exaggerated vowel U;

- Disclosure of the throat horizontally, like you do when pronouncing the vowel U;

- Deep but moderate inhale with the yawn using the diaphragm, abdominal muscles, back, etc.

All these techniques are aimed at stretching of the soft tissues of the mucous membrane covering the airways of the voice box and making them more resilient in order to improve the sound energy of the voice.

The main point is that the singer should be able to remember and to keep in mind the position of the articulatory apparatus in order to maintain it while singing - this is the essence of vocal placement. 

The stabilization of the larynx in singing is of particular importance. Regardless of vocal task (types of vowels or changes in the pitch), the throat should not be moved while singing. The preservation of inhalation at the level of the diaphragm and the optimal activity of the body muscles due to a certain vocal placement can be useful.  

The activity of the voice building system depends on the tone of all muscles. This illustrates the physiology: there is an intramuscular coordination in the human body as a complex system. That is why singing goes better in standing than in relaxed sitting. This also explains the need for a definite vocal placement and posture that helps to preserve the muscle activity of the whole body while singing.

The efficiency of the acoustic energy of the singing voice can be reached using the resonator system. Resonance of the voice is an essential element of the quality of the singing pitch. However, the lack of resonance or their exclusion from the singing process can also occur. A complete resonance also depends on muscle activity of the vocal apparatus and especially on the elasticity of the vocal tract and trachea walls.  

The singer should remember this feeling of "resonance". To practise this, there are special techniques:

- singing with the mouth closed at a certain position of articulation organs (jaws opened, constant feeling of a hidden yawn);

- tubularly twisted lips, closed slightly, but significantly pushed forward;

- singing with an inclined position of the body.

Pitch.

Pitch is a subjective perception of the oscillatory motion frequency of the sound source. The more often the periodic oscillations of the air occur, the higher the sound seems.

Increased vibration frequency of the sound source is related to the degree of active tension of voice building muscles.

The tension of the vocal folds does not show that they are constricted, it is just one of their positions. If the singer vocalises correctly, he doesn't notice the tension of the vocal folds that is created by the reflective interaction of various laryngeal muscles aimed to compensate the pressure of the subglottic air coming from the lungs. The tension resulting in the contraction of vocal folds is created with help of muscles that lie outside the larynx, in an attempt to squeeze them around it to control the height and intensity of the sound.

With an incorrect posture, fatigue or a bad mood while singing, the human muscular system can spontaneously relax, as a consequence of a protective reaction. It affects badly the purity of intonation.

The quality of intonation depends greatly on the condition of the body muscles while singing. Muscle activity is associated with a correct singing position. Positive emotions when singing, on which the muscle tone of the body and the voice box largely depends, can be of great assistance.

Among the natural sounds, we distinguish tonal sounds with their special pitch, and noises, different in their pitch. All the musical sounds are tonal, as they have a distinct note. Tonal sounds are produced when the source of vibrations moves repeatedly with a certain frequency.  

Noises are non-periodic oscillations, and therefore they don't have a certain height.

Human vocal tract can produce tonal sounds as well as noise while singing or speaking. All vowels are tonal in nature, and voiceless consonants consist of noise. In fact, if you listen to the sound of consonants like s, p, ch, tsh, you can easily determine their noise nature.

Larynx is the place in the vocal apparatus, where the quality of pitch originates. Human vocal folds are the source of sound; the voice pitch is determined by the frequency of their closure. There are no other mechanisms that could change the pitch after its formation in the larynx.

Specialities of the pitch perception by the person who hears it.

Our ear has its particularities of the pitch perception. One of them is that it is able to hear and distinguish not all the frequency. Our hearing is limited in the frequency range that lies from 16 to 20,000 Hz. The frequencies above and below this range are called infra- and ultrasound that the human ear can not hear. However, we perceive a range far exceeding those of singing voices: the low bass notes, such as D2-flat that has the amplitude of 60-70 Hz or high soprano notes like D in the third octave - 1200-1300 Hz.

People differ from others having a certain hearing, they perceive the accuracy of singer's intonation differently, and the accuracy of the pitch can be perceived differently. It depends on the ear for music, particularly for pitch, which by its nature can be absolute or relative.

People with perfect pitch have a very quickly establishing auditory memory to the stimulation with sound of a certain pitch that stands beside a certain note. People with relative pitch perception can also identify notes but they hear them as stages of the fret. But both of these categories show another feature of hearing: the zoned nature of the pitch perception. Thus, the absolute ear for music is not really absolute; it also has a zoned nature.

Our ear perceives as having the same pitch sounds that actually have different frequencies within a certain frequency band or zone. The width of the band of frequencies is different for each person. And of course: the finer it is, the thinner is the pitch perception. Highly qualified musicians frequencies have the width of this zone varying from 1/8 tone, or 25 cents. Every musician has his personal threshold of pitch perception that can be improved with training.

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