Being a Singer

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The mechanism of voice

A piano player doesn't really need to care about how the hammers and dampers and soundboard in their instrument work. Guitar players need to change their strings but they don't have to know much more than that about guitars.

We singers are in a different position. Every time we sing we are 'creating' - or more accurately 'lining up' our instrument. So we need to know in some detail how our instruments work.  

We refer to the entirety of 'the instrument' and the Vocal Tract. We must not forget that the vocal tract is entirely part of the body and that the posture and general condition of the body has a very great impact on the proper functioning of the vocal tract. 

The vocal tract begins at the diaphragm, which is a sheet of muscle extending across the bottom of the rib cage. The diaphragm is the main muscle of normal breathing and plays a major part in the control of air pressure for singing. When the lower (floating) ribs move forward, the abdominal wall moves forward with it, and the diaphragm moves downward into the created space. This lowers pressure in the lungs, drawing air in.

During singing, as the lower breathing exhale muscles act together on the bottom of the lungs, the lungs form a large reservoir of pressurised air. 

The tracheal tree is an upside-down Y shaped pipe leading from the lungs up to start of the throat. It carries the air.

At the top of the trachea is the larynx. This is a cartilage box containing the vocal cords (glottis) and its operating muscles. The vocal cords are more properly in science referred to as the Vocal Folds (they aren't cords...). They are a pair of  muscular folds, lined with mucous membrane, located inside the Larynx, one on either side. They can fold away to allow air to pass unrestricted to and from the lungs, or can be closed together (adducted) to either completely seal the opening to the trachea (as in swallowing, to prevent food entering the lungs) or slightly less firmly for the purpose of making sound - 'Phonation'.

During phonation the vocal folds are closed together and 

This air, trapped in the lungs by the closure of the glottis


The lungs contain the air, and in singing form a nice big reservoir of air

Singing is a conscious adaptation and extension of the body's inherited ability to make strongly resonant pitched cries.

The pure strong sound produced by this mechanism is recognisable to us as the singing voice.

The singing voice is a broad psychoacoustic channel which carries information about emotion and feelings.

To allow the body to produce the singing voice, we must learn to allow the throat to relax, and not allow speech habits involving throat tension or movement to interfere.

The overall singing mechanism involves the abdominal muscles and diaphragm, the larynx and vocal cords, and the upper vocal tract generally.

The function of these components is as follows:

  1. The abdominal muscles and diaphragm regulate the sub-glottal air pressure. Ultimately it is the muscular effort expended here, in the form of air pressure in the lungs (elastic potential energy) which is converted into sound. We must learn to introduce only enough energy into the system to produce the desired sound. Any more than that will be doubly wasted... at source where we are wasting energy blowing too hard, and at the upper vocal tract where muscular effort will be needed to counteract the excessive force of breath. In this case, the sound of the voice will be ruined.
  2. The larynx contains the vocal cords and the associated musculature. (The Glottis). The vocal cords operate by closing against each other across the top of the trachea, and when sufficiant sub-glottal air pressure is available, allow the passage of bubbles of air at audio frequencies. The precise frequency of vibration is set by the thickness and tension of the cords, as requested by the singer's mental envisioning of the pitch and monitored and corrected by the ear.
  3. The air pressure pulses exiting the larynx are acted on by the resonant chambers of the upper vocal tract to transform them into sound waves.  There are two major resonators: The pharynx and the nasal cavity. Resonance in the pharynx produces the sensation we feel as 'Chest Voice'. Resonance in the nasal cavity produces the sensation we identify as 'Head Voice'. The upper resonator (head) is fixed, that is we cannot alter it, and must submit strictly to the laws of acoutics as they apply. The lower resonator (chest) is adjustable within the range available to us according to the laws of acoutics. All notes of the singing range require both resonators to be operative. When the throat is relaxed, both resonators will function. Most vocal problems result from the inadvertent closure of one resonator. The mouth is a third area of resonance which is engaged in some vowels, and also acts as a moveable acoustic filter and articulatory device, thereby producing linguistic phonemes.