THE SOUND VOICE

© Shelagh Davies, M.Sc, S-LP(C) 

HOW THE VOICE WORKS

The voice is basically a wind instrument, like a flute or a pennywhistle, with one
fundamental difference – you don’t just play your instrument, you ARE your
instrument. Because it literally comes from you, nothing can express the inner soul
like the human voice. As a singer you have the potential to reach deep inside the
hearts of your listeners in a way that no other musician can.

All wind instruments have three

basic components that work
together to produce the sound.

For the voice these are: AMPLIFICATION SOURCE

Resonators

The power source –

SOUND SOURCE
the breathing system composed of Larynx
the lungs and respiratory muscles

The sound source –

the larynx, which changes the
breath into a sound wave POWER SOURCE
Breathing system

The amplification source–

the resonators - throat, nose
and mouth. Here, the sound is
amplified, shaped and turned into
what you recognize as your voice.
Figure 1: The Voice Production System
POWER SOURCE:
The Breath
When we want to sing or speak the brain sends signals to the breathing
muscles, and in particular, to every singer’s favorite muscle – the diaphragm.
The diaphragm is a thick, dome shaped muscle that divides the body into
two halves. Above it are the heart and lungs and below it are the stomach
and other organs such as the liver, kidneys and intestines.

At rest the diaphragm sits in the middle of the body like an upside down
soup bowl. When you breathe in, it contracts and flattens, and the soup
bowl becomes a plate. As it flattens, the diaphragm pulls the chest cavity
downward with it and air is sucked into the lungs. This movement pushes
the chest cavity down against the abdomen, causing the abdominal
organs to move slightly outward. You feel the middle of your body gently
expanding and contracting with your breathing. It feels as if the air is
flowing into your belly. It isn’t. The only place the air goes is into the lungs.
 THE SOUND VOICE
© Shelagh Davies, M.Sc, S-LP(C)

DIAPHRAGM

Figure 2a : Full lungs Figure 2b : Empty lungs

When it has finished its descent the diaphragm relaxes back up towards the
bottom of the lungs, pushes the air out and then the whole cycle begins again.

While the diaphragm may do most of the work when you breathe in, the muscles
between the ribs are also active. One set of these pulls the lower ribs up and out,
rather like handles on a bucket. This action helps expand the chest cavity and sucks
air into the lungs. You can feel this action if you put your hands over your lower ribs
and breathe for a while. The ribs lift and the air goes in; the ribs fall and the air goes out.

When you are not doing anything in particular, small movements of the diaphragm
and rib muscles are all you need to maintain your life’s breath. Your body is efficient.
It won’t work harder than it needs to.

When you sing, however, things are quite different.

The diaphragm descends farther, the rib muscles
expand the ribcage more vigorously, and you take
more air into the lungs. Then, when your lungs are
as full as they need to be, the breathing muscles
carefully manage how the air is driven back out
of the lungs and up to the larynx. The diaphragm
and the rib muscles squeeze out exactly the right
amount of air for each note.

Good singing depends upon this exquisite balance

of forces in the breathing system. For example
higher, louder notes take more air; softer, lower
Figure 3 : Rib movements notes take less. A whole host of other things
- like lung volume, phrase length and consonant
articulation will affect the amount of work required
of the breathing muscles. The equation is staggeringly complex and fortunately the
brain figures it out as we go. However, breathing for singing is a learned skill. The
more accomplished you are as a singer, the more efficiently your body makes these
calculations.
 THE SOUND VOICE
© Shelagh Davies, M.Sc, S-LP(C) 

SOUND SOURCE: The Larynx

There is only one way into and out of the lungs and that is through the windpipe.
The entrance to the windpipe is the voice box, or larynx (pronounced lar-inks).
Everyone is pretty familiar with the front view of the larynx; it is the Adam’s Apple
(technically known as the thyroid cartilage). This bone-like structure protects the
larynx and provides an attachment point for the front of the vocal folds

From the inside, the larynx is definitely unfamiliar territory to most of us. There is
no way you can see inside your own larynx without special mirrors, a lot of practice,
and a very weak gag reflex.

Deep inside the larynx are the vocal folds – 2 strips of muscle covered with a white
mucosal membrane that flaps in the breeze when they vibrate. The vocal folds are
small – somewhere around 1 centimeter in women and up to 1 1/2 centimeters in
men – and positioned horizontally in the throat, parallel with the floor. The vocal
folds and the area between them would roughly fit inside a postage stamp. Quite
frankly, the vocal folds look like pretty insignificant, nondescript structures and it is
hard to imagine they are responsible for producing the beautiful sounds that some
people make.

The vocal folds are joined at the front and stretch back across the opening to the
windpipe. At the back, each fold attaches separately to a cartilage. These cartilages
tilt and swivel to change the length and position of the folds. When you are
breathing quietly, the folds are in a “V” shape that allows air to pass through them. If
you have just run up 4 flights of stairs and are gasping for air, they open a lot wider.
When you sing or speak, the vocal folds come together to meet in the midline, close
enough to be vibrated by the air from the lungs.

FRONT VIEW SIDE VIEW

Hyoid Bone

Epiglottis

Larynx
Thyroid cartilage

Cricoid cartilage

Trachea

Figure 4: Larynx
 THE SOUND VOICE
© Shelagh Davies, M.Sc, S-LP(C)

The Vocal Folds and the Voice:

LARYNX (top view)
When they are in this midline position, almost
touching each other, the vocal folds are ready
1 - 1.5 cm to produce the voice. The air flows up from the
CANADA lungs and the vocal folds begin to vibrate in a
rapid, complex, rippling motion, chopping the
vocal folds airstream into little puffs. This turns the direct
current of air into an alternating current of
Figure 5 : Vocal folds - approximate life size
sound.

The pitch of the voice depends upon the number of times the vocal folds vibrate per
second - the faster the vibration, the higher the pitch. For a man’s voice in speaking
range, the vocal folds vibrate, on average, around 100 – 130 times per second; for a
woman’s voice it is in the range of 180 – 220 times per second. For guys, when you
are singing in falsetto, the vocal folds could be vibrating up to 500 or so times per
second, and when a classical soprano sings a high C, her vocal folds are vibrating at
over 1000 times per second!

Vocal Folds (top view)

Larynx
RELAXED VIGOROUS VOCALIZING
BREATHING BREATHING
Figure 6 : Vocal fold positions

Of course, in the human body, nothing is simple. This vocal fold vibration is very
complex - the folds meet from back to front, bottom to top, and the mucosal
membrane flows over each fold like a wave rippling on the seashore. Other things
affect the way vocal folds vibrate. The amount of air pressure from the lungs, how
tightly the folds are approximated, and the set of the muscles around the larynx all
can alter the way the folds meet and part.

You can imagine that a sound generator this complex produces an equally complex
sound wave, full of potential harmonics that add richness and character to the voice.
You can also see that there can be a huge amount of variation in how well the system
works. Even a small amount of extra tension around the vocal folds can affect the
way they vibrate. And because the folds vibrate SO MUCH, a small amount of
 THE SOUND VOICE
© Shelagh Davies, M.Sc, S-LP(C) 

tightness can have a big effect. You can also begin to see how your vocal folds’ health
can be affected by things like:

• how much you use your voice

• how hard the impact is when the vocal folds meet

• whether the folds are well lubricated or dry

The Larynx and Swallowing: DID YOU KNOW?

Some singers might disagree, but the most • THE ADAM’S APPLE...
important function of the larynx is actually not You may have noticed that the Adam’s
to produce the voice, but to protect the lungs. Apple is a lot easier to see in men than
Every time we swallow it acts as a valve, women. This is because the whole
squeezing tightly shut. structure is bigger and the angle of the
thyroid cartilage is sharper and more
The only thing that should go into your lungs is air. prominent.
The lungs do not like foreign objects. If anything goes
• CORDS OR FOLDS...
down the wrong way you know about it.
You double over, coughing and gasping, until Vocal cords and vocal folds mean the
same thing. Doctors tend to talk about
you have got rid of the offending morsel. You will
vocal cords; voice scientists prefer the
also have given a very neat demonstration term “vocal folds”. “Vocal cords” is more
of the other two basic functions of the larynx: common, but strictly speaking, “vocal
folds” is more accurate.
1. to protect the airway during swallowing
• SEEING THE VOICE IN ACTION...
2. to act like a valve so that you can cough out the
On this website you can view video
stuff that shouldn’t have got down there in the
material of the vocal folds in action!
first place www.voicedoctor.net/media/video

So how does a swallow actually work?

Food, drink and air all share the same passage through the mouth and upper throat,
down to the level of the larynx, then things get a little complicated. When you
swallow:

• the larynx rises and the vocal folds shut firmly together.

• other muscles on top of the larynx shut tightly and seal off the entrance
to the windpipe.

• whatever was in your mouth is propelled into passages on either side of

the larynx, and thence down into the esophagus.

The main biological function of the larynx is to act as a gatekeeper to the lungs: air
down the centre, lunch round the sides. The reason I am mentioning this is to let
you know that your throat has some pretty strongly wired biological functions and is
well equipped with muscles that act as a valve. They tighten, squeeze, and close.
 THE SOUND VOICE
© Shelagh Davies, M.Sc, S-LP(C)

Food / Drink

EPIGLOTTIS

LARYNX
TRACHEA
ESOPHAGUS

Figure 7: Swallowing

Tighten - squeeze - close … possibly familiar feelings when you sing? The swallowing
muscles are strong and used to acting on automatic pilot. When you are speaking
and singing you want them to stay uninvolved and neutral so the larynx can act as
a vibrator and not a valve. Training the throat muscles to allow vibration without
constriction is part of what good voice technique is all about.

AMPLIFICATION SOURCE: The Resonators

If you take a larynx that someone doesn’t need any more, mount it in a frame and
drive air through it, the vocal folds will vibrate. The sound they make is thin and
quiet. It doesn’t sound like a human voice at all, which is hardly surprising when
you consider that the whole top of the vocal tract is missing. The upper vocal tract is
the final part of the voice production system, and it makes dramatic changes to the
sound.

The rich, complex sound wave produced in the larynx travels upward into the
cavities of the throat, mouth and nose. Here the sound behaves as it would in any
large, empty place: it resonates. It takes on the character of the space it is echoing
around in. Some frequencies are amplified, some are damped, and by the time the
sound wave hits your lips it has been profoundly altered. It has been turned into
your voice rather than someone else’s. Everyone’s voice is unique, just like everyone’s
fingerprints, and differences in the resonance system have a lot to do with this.

The resonance system also makes your voice louder without any added work on
your part. By simply passing through the relatively large cavities of the mouth and
throat the sound is automatically amplified. As a singer you can actually “tune” your
resonating system to give you a louder, richer sound – all without straining your voice!
When you do this, you get a big buzzy feeling in your face and your throat feels
open and relaxed. It feels great and it is very powerful.
 THE SOUND VOICE
© Shelagh Davies, M.Sc, S-LP(C) 

The mouth, nose and throat are

the only resonators that shape the
voice directly, because the sound
wave actually passes through
them on its way outside. But the
sound wave produces sympathetic
vibrations throughout the body. NASAL CAVITY
It will vibrate in hard structures MOUTH
like bones and open spaces like
the chest cavity or sinuses. When
singers talk about “chest voice” or THROAT
“head voice” they are referring to
these resonance sensations. Even
though these kinds of resonance
don’t directly affect the sound,
they can give you valuable, instant
Figure 8 : Resonators
feedback about how you are
producing your voice.

TURNING THE VOICE INTO WORDS

So far we have been talking just about the voice – the sound/noise component of
speech. At the back of your throat the voice is simply raw sound but by the time
it leaves your lips it has been transformed into speech. In between, the voice is
stopped, started, amplified, squeezed, aerated, exploded and narrowed. It is turned
into words by a series of precise, high-speed maneuvers. This shape-changing is done
by the muscles in the walls of the mouth and throat and also by the articulators: the
tongue, lips, jaw, and soft palate. Speech scientists have recorded all this on x-ray
film, and it is wonderful to watch the beautifully timed, precise dance of the vocal
tract in action.

So producing the voice and speech is one of those paradoxes. It is so simple we aren’t
conscious of doing it and so complex that - if we had to do it consciously - we would
never get it done at all.

Shelagh Davies, M.Sc., S-LP(C), Registered Speech-Language Pathologist

Graphic Design and Illustrations by Helma Sawatzky