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Voice
types and the anatomy of the vocal cords.
The human voice consists of
sound made by the vocal folds or 'cords' for talking, singing,
laughing, crying and screaming. The vocal folds, in combination
with the lips, the tongue, the lower jaw, and the palate, are
capable of producing highly intricate arrays of sound. The tone
of voice may be modulated to suggest emotions such as anger,
surprise, or happiness.
A
diagram of the Vocal folds or cords.
Men and women have different
vocal cord sizes; adult male voices are usually lower-pitched
and have larger cords. The male vocal cords (which would be measured
vertically in the opposite diagram), are between 17 mm and 25
mm in length. Female
vocal cords are between 12.5 mm and 17.5 mm in length.As seen in the illustration,
the cords are located just above the trachea (the windpipe which
travels from the lungs).
Food and drink does not pass through the
cords but is instead taken through the eosophagus , a separate
tube. Both tubes are separated by the tongue and an automatic gag
reflex. When food goes down through the cords and trachea it causes
choking.Cords are ligaments within the
larynx. They are attached at the back (side nearest the spinal
cord) to the arytenoid cartilages, and at the front (side under
the chin) to the thyroid cartilage. Their outer edges, as shown
in the illustration above, are attached to muscle in the larynx
while their inner edges or "margins" are free (the hole).
They are constructed from epithelium, but they have a few muscle
fibres on them, namely the vocalis muscle which tightens the front
part of the ligament near to the thyroid cartilage. They are flat
triangular bands and are pearly white in colour—whiter in
females than they are in males.
The
difference in vocal cord size between men and women means that
they have differently pitched voices. Additionally, genetics also
causes variances amongst the same sex, with men and women's voices
being categorised into types. For example, among men, there are
basses, baritones and tenors, and altos, mezzo-sopranos and sopranos
among women. There are different methods for categorizing voices,
such as the fach in German opera, and vocal weight in British opera.
Vocal
registration
The human voice is capable
in most cases of being a complex instrument. Humans have vocal
folds which can loosen or tighten or change their thickness and
over which breath can be transferred at varying pressures. The
shape of chest and neck, the position of the tongue, and the
tightness of otherwise unrelated muscles can be altered. Any
one of these actions results in a change in pitch, volume, timbre,
or tone of the sound produced. One important categorization
that can be applied to the sounds singers make relates to the register or
the "voice" that is used. Singers refer to these registers
according to the part of the body in which the sound most generally
resonates, and which have correspondingly different tonal qualities.
There are widely differing opinions and theories about what a register
is, how they are produced and how many there are. The distinct
change or break between registers is called a passaggio or a ponticello.
The following definitions refer to the different ranges of the
voice.
The chest voice is the register
typically used in everyday speech. The first recorded mention
of this register was around the 13th century, when it was distinguished
from the throat and the head voice (pectoris, guttoris, capitis
-- at this time it is likely head voice referred to the falsetto
register. The speaking voice is named as "the
chest voice" in the Speech Level Singing method. It is so
called because it can produce the sensation of the sound coming
from the upper chest. This is because lower frequency sounds have
longer wavelengths, and resonate mostly in the larger cavity of
the chest. A person uses the chest voice when singing in the majority
of his or her lower range.The tonal qualities of the chest
voice are usually described as being rich or full, but can also
be belted or forced to make it sound powerful by shouting or screaming.Use of overly strong chest voice
in the higher registers in an attempt to hit higher notes in the
chest can lead to forcing. Forcing can lead consequently to vocal
deterioration.
Falsetto
In falsetto, the vocal folds,
or cords when viewed with a stroboscope are seen to be blown
apart and a permanent oval orifice is left in the middle between
the edges of the two folds through which a certain volume of
air escapes continuously as long as the register is engaged (the
singer is singing using the voice). The arytenoid cartilages
are held in firm apposition in this voice register also. The
length or size of the oval orifice or separation between the
folds can vary, but it is known to get bigger in size as the
pressure of air pushed out is increased. The folds are made up of elastic
and fatty tissue. The folds are covered on the surface by laryngeal
mucous membrane which is supported deeper down underneath it by
the innermost fibres of the thyro-arytenoid muscle. In falsetto
the extreme membranous edges, ie the edges furthest away from the
middle of gap between the folds appear to be the only parts vibrating.
The mass corresponding to the innermost part of the thyro-arytenoid
muscle remains still and motionless.Some singers feel a sense of
muscular relief when they change from chest voice to falsetto.In women, the falsetto voice
refers to the whistle register.Generally when singers describe
their range they exclude the falsetto voice. A classical male singer
who routinely sings using the falsetto is called a countertenor.
Countertenors tend to count this range. If a singer makes frequent
use of their falsetto it may be counted as part of their vocal
range.
The head register is used in
singing to describe the resonance of singing something feeling
to the singer as if it is occurring in their head. It's mentioned
in the Speech Level Singing method used in some singing. All
voices have a head register, whether bass or soprano. It is not
associated with any particular musical pitch, but rather with
the resonance of the voice in the head. The head register is sometimes
called "the mask" by vocalists and singers because resonation
from the voice is felt in the sinus cavities behind and around
the eyes and nose. But often explanations for the physiological
mechanisms behind the head voice alter from voice teacher to voice
teacher. This is because, according to Clippinger: "In
discussing the head voice it is the purpose to avoid as much as
possible the mechanical construction of the instrument".
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