The Physiology And Psychology Of Voice-production
Above this chapter I might well have placed the following lines which
George Eliot wrote above Chapter XXXI. of "Middlemarch."
How will you know the pitch of that great bell,
Too large for you to stir? Let but a flute
Play 'neath the fine-mixed metal! Listen close
Till the right note flows forth, a silvery rill:
Then shall the huge bell tremble--then the mass
With myriad waves con
urrent shall respond
In low, soft unison.
The lines telling of the great bell stirred by the note of a flute
played at the proper pitch suggest the moving power that lies in
sympathetic vibration. The first time a military body crossed the
Brooklyn Bridge, the spectators were surprised to hear the order given
for the soldiers to march out of step. They had expected to be thrilled
by the sight of a thousand men crossing the great structure in measured
tread, with band playing and colors flying. They did not know that the
structure, being a suspension bridge, might have been weakened and
possibly destroyed by the force of rhythmic oscillation. Yet the
accumulated force in the tramp of a thousand men is no greater than that
which lies in the sympathetic vibrations of a musical note. Every metal
structure has its note, and it is an old engineering saw that a huge
structure like the Brooklyn Bridge eventually could be destroyed by the
cumulative force of sympathetic vibration evoked by a musical instrument
constantly reiterating the note of the bridge.
Sound has three dimensions: pitch, loudness and timbre.
Pitch depends upon the frequency of vibrations. The more rapid the
vibrations, the higher the pitch.
Loudness is determined by the amplitude of the vibrations. As their
length or "excursion" increases, so does the sound gain in loudness.
Conversely, the diminution in the size of vibrations causes
corresponding decrease of loudness.
Differences in the shapes of vibrations cause differences in quality
or timbre.
After voice has originated within the restricted limits of the larynx,
its power, its carrying quality is much augmented by the sympathetic
vibrations within the resonance cavities above the larynx. These include
the pharynx, nasal passages, mouth, bone cavities of the face--in fact
pretty much every hollow space in the head, every space that will
resound in response to vibration and assist in multiplying it. Moreover,
the cavities of resonance by their differences in shape in different
individuals determine the timbre or quality of individual voices. The
chest, although situated below the larynx, is a resonance cavity of
voice. In fact, in a certain register its vibration is felt so
distinctly that we speak of these notes as being sung in the "chest
register," which, so far as it implies that the tones are produced in
the chest, is a misnomer. The same is true of "head register," in which
vibration is felt in the head where, however, it is needless to say,
the "head tones" do not originate.
Expiration--breath-emission--is the motor function of the vocal organs;
and there are two other physical functions of the organs--vibratory and
resonant.
Added to these is the sensory function, to which I attach great
importance; and I call it a psychological function because it acts
through the nerves upon the physical organs of voice. Without it the
three physical functions--motor, vibratory and resonant combined--would
remain ineffectual. They could generate voice, but it would be voice
lacking those higher qualities that are summed up in the word
"artistic." It would be a physical, not an art product, a product
generated by the body without the cooperation of the mind or soul. When
it is considered that the larynx, in which the vocal cords are situated,
is permeated by a network of muscles through which it is capable of some
16,000 adjustments and readjustments of shape, all of them pertinent to
voice-production, and that the same thing also is true of the pliable
portions of the resonance cavities; that these muscles act in response
to an even finer network of nervous filament; and that the constant
shaping and reshaping of various parts of the vocal tract during
voice-emission is directed by messages from the mind, soul, or art-sense
of the singer, messages which travel via nerve to muscle--the only route
by which they can travel--it becomes possible to appreciate the
importance of the sensory or psychological function which, I hold,
should be added to the purely physical ones of motor, vibration and
resonance. For by it these functions are enlisted in the service of
art and made immediately and exquisitely responsive to the emotional
exaltation of music and song. Nor are these vague terms. Psychology
of song and psychological action in general may seem indefinite and
unintelligible. They become, however, absolutely definite and
intelligible when the part played by the nerves as intermediaries
between mind and muscular action of a subtle and highly refined order
is appreciated. The mind presses the button, the nerves carry the
messages, and muscle acts instantaneously and responsively.
The student need not despair because so many separate acts seem
necessary to the production of even a single tone. It is true that air
has to be taken into the lungs and emitted from them; that it must be
controlled by the singer as it passes up the windpipe; that the vocal
cords and other parts of the larynx must be given their specific
adjustment for each note; and the cavities of resonance shaped in
sympathetic coordination with those numerous adjustments, while the lips
also have their function to perform. But it is equally true that correct
instruction supplemented by assiduous practice merges all these separate
acts into one. The singer thinks the note, forms what may be called a
sounding vision of it in his mind, and straightway the vocal tract
adapts and coordinates all its parts to the artistic emission of that
note. It is auto-suggestion become habit through practice.
Because the larynx is so important a factor in generating voice,
writers on voice-production have described it with much minuteness,
and because of these minute descriptions readers may have obtained an
exaggerated idea of the size of this organ. But one of the marvels of
voice-production is the smallness of the organ in which voice is
generated, the size of the average larynx being about two inches in
height by an inch and a half in width. Yet so numerous are the
adjustments in shape of which this small organ is capable that the
phenomenal soprano, Mara, could make 100 changes in pitch between any
two notes in her voice, and as this had a compass of twenty-one notes,
it follows that she could produce no less than 21,000 changes in pitch
within a range of twenty-one notes. While in Mara's day this no
doubt was attributed to a natural gift of voice, modern study of
voice-physiology and of the metaphysics of voice-production readily
accounts for it. It needs an ear naturally or by training so
delicately attuned to pitch that not only all the fundamental notes of
a voice, but all the numerous overtones at infinitesimal intervals are
heard in what may be called the singer's mental ear; that the nerves
convey each of these sounding mental conceptions to the intricate
system of muscles in the larynx and resonant cavities and that the
right muscles immediately adjust the larynx and cavities of resonance
to the shape they have to assume to sound the corresponding note.
Every vocal tone is, in fact, a mental concept reproduced as voice by
the physical organs of voice-production, so that every vocal tone is,
in its origin, a mental phenomenon. That is why an inaccurate ear for
pitch results in a vocalist singing off pitch. His mental conception
of the note is wrong, the message conveyed from the mind over the
nerves to the muscles of the vocal organs is wrong, consequently they
shape themselves for a note that is wrong, and, when the note issues
from between the singer's lips, it is wrong--wrong from start to
finish, from mind to lips. Thus again is illustrated the intimate
connection between psychology and physiology in voice-production, and
the necessity of having every function concerned therein so thoroughly
trained that every act from mental concept to sounding voice is
correctly performed through a habit so thoroughly acquired that it has
become second nature. In common parlance one might say to the student
of song, "Get the correct voice-habit and keep it up," for that really
is what it amounts to, only it is necessary that great stress should
be laid on the word "correct."
It now becomes necessary to describe the larynx, and this I will
endeavor to accomplish without puzzling the reader with too many
technical terms. The study of the larynx was made possible by the
invention of the laryngoscope in 1855 by Manuel Garcia, a celebrated
singing-master. It is a simple apparatus--which, however, does not
detract from but rather adds to its value as an invention--and has been
a boon to the physician in locating and curing affections of the throat.
Its essentials are a small mirror fixed at an obtuse angle to a slender
handle. Introduced into the mouth it can be placed in such position
that the larynx is reflected in the mirror and thus can be observed
by the operator. Those who have had their throats examined with the
laryngoscope will recall that the operator wears a reflector over his
right eye. Through a central perforation in the reflector he views the
image, which is seen the more clearly for the light thrown upon the
laryngoscopal mirror by the reflector. It would be possible after
comparatively little practice with the apparatus for a singer to examine
his own larynx. But it would be most inadvisable for him to do so.
Either he soon would become "hipped" on the subject of innumerable
imaginary throat troubles, or his voice-production would become
mechanical, which is very different from the spontaneous adjustment
of the vocal tract described above.
N. B.--Vocal cords approximated]
1, Glottis. 2, True Cords. 3, False Cords. 4, Epiglottis. 5, Base of
Tongue. N. B.--Glottis open for inspiration]
1, Glottis. 2, True Cords. 3, False Cords. 4, Epiglottis. 5, Base of
Tongue. N. B.--Vocal cords approximated]
1, The Glottis (i. e., the opening between the opposed edges of the
Vocal Cords). 2, True Vocal Cords. 3, False Vocal Cords. 4, Epiglottis.
(N. B.--In singing, the "true cords" are closely approximated.)
V, Ventricles. T, Thyroid Cartilage. C, Cricoid Cartilage. W, Windpipe
or Trachea.
(N. B.--In STRAINING, the "false cords" are closely approximated.)]
The laryngoscope should not, in fact, leave the hands of the physician.
Invaluable for the detection of diseases of the throat which impair the
voice and which have to be cured either by treatment or operation before
the voice can be restored to its original potency or charm, its value
in studying the physiology of voice-production and the functions of
the vocal organs is doubtful. In fact, it is its use by amateur
laryngoscopists that has resulted in the promulgation of all kinds of
absurd theories of voice-study and in those innumerable pet methods of
vocal instruction, each one of which may safely be guaranteed to destroy
expeditiously whatever of voice originally existed. Fascinating as it
may seem to the singer to examine his own larynx while he is producing a
vocal tone--"during phonation," the physiologist would say--the value of
the deductions formed from such observation may be doubted, if for no
other reason than that the introduction of the mirror into the back of
the mouth makes the whole act of phonation strained and the effects
observed unnatural. In fact, as Mackenzie already has pointed out,
although the laryngoscope is invaluable in the recognition and treatment
of diseases which before only could be guessed at, "with the exception
of certain points relating to the 'falsetto' register, it can scarcely
be said to have thrown any new light on the mechanism of the voice." In
other words, the instrument belongs in the hands of the physician, not
in those of the singer.
The larynx, as I already have stated, is a small organ, on an average
two inches long and one and a half inch wide. The reader can form a good
idea of its location by the Adam's apple, which is its most forward
projection at the top.
From the singer's point of view the larynx exists for the sake of the
vocal cords--in order that they may be acted upon by certain muscles and
thus relaxed or tightened, lengthened or shortened, or by a combination
of these states properly adjusted to the note that is to be produced.
The vocal cords lie parallel to each other. The space between them
(the opening through which the air from the windpipe passes up into
the larynx) is called the glottis. With every loosening, tightening,
lengthening or shortening of the vocal cords or other effect of
muscular action upon them, the space between them--the glottis--alters
in size and shape. These subtle changes in the size and shape of the
glottis are, as I shall expect to show, of great importance in
voice-production. They form the first step in the actual creation
of voice.
The numerous and subtle adjustments and readjustments in shape of which
the larynx is capable could not be effected if its shell consisted of so
hard and unyielding a substance as bone. Consequently, it has to consist
of a substance which, while sufficiently solid to form a background for
the attachment of its numerous muscles, yet is sufficiently pliable to
yield with a certain degree of elasticity to the action of these. Nature
therefore has built up the larynx with cartilage, or gristle, providing
a framework made up of a series of cartilages, sufficiently joined to
form a firm shell surrounding the muscular tissue, yet, being hinged as
well as joined, capable of independent as well as of combined movement,
and, withal, possessing the requisite degree of pliability to respond in
whole or part to the extremely varied and often delicate action of the
laryngeal muscles--muscles which indeed are required to be as practised
and as sensitive to suggestion as if they were nerves.
The principal cartilage of the larynx is the thyroid or shield
cartilage, named from the Greek thureos (shield). It really consists
of two shields joined along the edges in front (its most forward upper
projection being the Adam's apple) and opening out at the back. The
thyroid is the uppermost cartilage of the larynx and the Adam's apple
is the uppermost portion of the front of the larynx. But as the shields
open out back of the Adam's apple, they slope upward and at the extreme
back each shield has a marked upward prolongation like a horn. By these
horns, enforced by membrane, the thyroid cartilage and through it the
whole larynx is attached to and is suspended from the hyoid bone, or
tongue-bone. This gives mobility to the larynx and freedom of movement
to the neck; and the larynx, while mobile as a whole, furthermore is
capable of an infinite number of muscular adjustments and readjustments
within itself.
At the back the lower edges of the thyroid rest upon the cricoid
cartilage, which derives its name from the Greek krikos, a
signet-ring. This is next in size to the thyroid. The broader portion,
the part which corresponds to the seal in a signet-ring, is at the
back. Attached at the back, the two cartilages do not, however, meet in
front. Place a finger on the Adam's apple, slide it down a little way,
and the slight depression there met with locates the front opening,
covered with yielding membrane, between the thyroid and cricoid
cartilages.
On the broader part of the cricoid--that is, on the part in the back of
the larynx--and rising inside the thyroid are two smaller cartilages,
the arytenoid or ladle cartilages, named from the Greek arutaina, a
ladle. Though smaller than either thyroid or cricoid, they are highly
important, because they form points of attachment for the vocal cords.
These (the vocal cords) are attached in front to the inner part of the
angle formed by the two wings of the thyroid just back of the Adam's
apple, and behind to a forward projecting spur at the base of each of
the arytenoid cartilages, which for this reason often are spoken of as
the "vocal process."
The vocal cords, as has been stated, lie parallel to each other, and
the space between them is known as the glottis or chink of the glottis.
Above the glottis and on opposite sides are two pockets or ventricles,
and above these are the so-called false cords or ventricular bands. The
pockets are, in fact, bordered below by the vocal cords and above by
the false cords. The false cords or ventricular bands (a name given to
them by Mackenzie) are the lower edges of membranous folds that form the
upper entrance to the larynx. Here are two pairs of small cartilages,
the cartilages of Santorini and the cartilages of Wrisberg. Usually
they are dismissed as of little or no importance. Yet they have, in
connection with muscles located in that part of the larynx, their roles
to play in those numerous adjustments and readjustments which, as I
shall show a little later on, are of the greatest importance in
voice-generation. For I consider, as I also will show, that the
numerous, indeed innumerable, and extremely subtle and exquisite
changes of shape of which the larynx is capable within itself, have
much to do with the actual creation of the tone which eventually issues
from the lips; although I believe this statement to be contrary to all
accepted authority. For the present, however, I must content myself
with this mere statement.
The larynx is protected above by a lid, a flexible, leaf-shaped
cartilage, the epiglottis. The gullet, or food-passage to the stomach,
is situated behind the larynx and windpipe, and the function of the
epiglottis is to close the larynx and to act as a bridge over which
food passes from the mouth into the gullet. But for the epiglottis, food
might get into the larynx and thence into the windpipe every time we
swallowed, with what distressing and even disastrous effect any one who
has ever "swallowed the wrong way" well knows. When open, on the other
hand, the epiglottis forms a beautifully smooth cartilaginous curve,
over which the sounding air, the tone, as it issues from the larynx,
is guided to the resonance cavities above the larynx, which are the
cavities of the mouth and of the nose. While parts of these cavities are
solid, like the roof of the mouth, other parts, like the soft palate,
are pliable; while the tongue is so astoundingly mobile that it
constantly can alter the resonance cavity of the mouth as to dimension
and shape.
The larynx is swathed and lined with membrane and muscle. These
membranes and muscles are named after the cartilages to which they are
attached, between which they lie, or which they operate. There is no
reason why they should be enumerated now. The function of the muscles
of the larynx is stated by all authorities with which I am familiar to
be twofold--to open and close the glottis (the space between the vocal
cords), and to regulate the tension of the vocal cords, because the
vibrations of these are considered the determining factor of vocal
pitch. Sir Morell Mackenzie, however, in describing the muscles of the
larynx in a passage couched in untechnical language, unconsciously gives
a hint of another purpose for which the complexity of muscles in the
larynx may exist. After speaking of the "innumerable little fingers of
the muscles which move the vocal cords," he continues: "These fingers
(which prosaic anatomists call fibres), besides being almost countless
in number, are arranged in so intricate a manner that every one who
dissects them finds out something new, which, it is needless to say, is
forthwith given to the world as an important discovery. It is probable
that no amount of macerating or teasing ever will bring us to 'finality'
in this matter; nor do I think it would profit us much as regards our
knowledge of the physiology of the voice if the last fibrilla of tiny
muscle were run to earth. The mind can form no clearer notions of the
infinitely little than of the infinitely great, and the microscopic
movements of these tiny strips of contractile tissue would be no more
real to us than the figures which express the rapidity of light and
the vast stretches of astronomical time and distance. Moreover, no two
persons have their laryngeal muscles arranged in precisely the same
manner--a circumstance which of itself goes a considerable way toward
explaining the almost infinite variety of human voices. The wonderful
diversity of expression in faces which structurally, as we may say,
are almost identical, is due to minute differences in the arrangement
of the little muscles which move the skin. The same thing holds good of
the larynx."
These are significant words. The distinguished physician who wrote them
might just as well have said that the generally prevailing theory that
in voice-production the muscles of the larynx exist solely to open and
close the glottis and to regulate the tension and hence the vibration of
the vocal cords, is incorrect. For they also exist in order to shape and
reshape the entire larynx within itself according to the note to be
produced, and the opening or closing of the glottis with the degree of
tension of the vocal cords resulting therefrom is but one detail in the
coordination of adjustments and readjustments which prepare the vocal
tract to produce the tone the singer hears in his mind. Nearly every
authority on the physiology of voice-production believes that the vocal
tone is produced solely by the vibration of the vocal cords, and that
the entire vocal tract situated above the vocal cords is concerned
merely with augmenting the tone and determining its timbre or quality.
Let us examine this theory and ascertain how tenable it is.
To begin with, the term "cord" as applied to the vocal cords is
misleading. It suggests a resemblance between the vocal cords and the
strings of a violin, which are capable of great tension, or at least
a resemblance between the vocal cords and the vibrating reed of a
reed-instrument. In point of fact, the vocal cords are neither strings
nor reeds, and are not even freely suspended from end to end or from one
end like reeds, but are attached along their entire lower portion to the
inner wall of the larynx. Therefore they are not cords, nor strings, nor
reeds in any sense whatsoever. They are shelves composed of flesh and
muscle, their substance resembles neither the catgut of which the
strings of stringed instruments are made nor the cane, wood or metal of
which the reeds of reed-instruments are formed; and the entire length of
each cord is a trifle more than half an inch in men and a little less
than half an inch in women. Almost every writer on voice appears to
consider the term "cord" as applied to them a misnomer. They have been
spoken of as membranous lips. "The vocal 'cord' is not a string, but
the free edge of a projecting fold of membrane," says Mackenzie. Yet it
is not only claimed but announced over and over again as a physiological
fact that the human voice, sometimes sweet and mellow, sometimes
tense and vibrant and with its great range, is produced solely by the
vibration of two projecting folds of membrane, free only at their edges
and at their longest only a little over half an inch in length.
At least one writer on voice-production, Prof. Wesley Mills, appears to
have doubted the correctness of the old and oft-repeated theory.
"Allusion must be made," he writes in "Voice-Production in Singing and
Speaking," "to the danger of those engaged in mathematical and physical
investigation applying their conclusions in too rigid a manner to the
animal body. It was held until recently that the pitch of a vocal tone
was determined solely by the number of vibrations of the vocal bands,
as if they acted like the strings of a violin or the reed of a clarinet,
while the resonance chambers were thought to simply take up these
vibrations and determine nothing but the quality of tone.... It seems
probable that the vocal bands so beat the air within the resonance
chambers as to determine the rate of vibration of the air of these
cavities, and so the pitch of the tone produced." This at least shows
dissatisfaction with the old theory and attaches some share of their
due importance to the resonance cavities, but it still is far from
describing the correct phenomenon of voice-production.
Show a lateral section of a larynx to a trumpet or horn player and he
will at once recognize its similarity to the cupped mouthpiece and tube
of trumpet or horn, the cup in the larynx being formed by the ventricles
or pockets above the vocal cords. Extend the picture so that it includes
not only the larynx but the resonance cavities of the head as well, and
the cornet, trumpet or horn player will recognize the similarity to the
tube of his instrument as it turns upon itself. The manner in which the
lips shape themselves as the player blows into the instrument, the form
and size of the cup, the gyration and friction of the air within it and
within the bent portion of the tube, determine the pitch and the quality
of the tone that issues from the bell of the instrument.
The shape assumed by the lips, which are capable of many exquisite
variations in shape, conditions the form of the air-column as it enters
the cup of the trumpet or horn. This I believe to be one important
function performed for the larynx by the vocal cords, which Mackenzie,
with an aptness he could not have appreciated, called the lips of the
glottis. They are, in fact, the lips of the essential organ of voice,
the larynx. If they are looked at from below they will be seen to be
bevelled, and their resemblance to lips even more striking.
While, however, the importance of the vocal cords in tone-production
has been overestimated, I should be going to the opposite extreme if I
limited their importance to their function as the lips of the glottis.
Not only are they lips, but vibrating lips, their vibrations, however,
requiring enforcement through the sympathetic vibrations which they
generate within the cup of the larynx and in the cavities above. As
lips, the vocal cords shape the air-column as it enters the larynx, to
the required note; as vibrating lips--set into vibration by the very
air-column to which they have given shape--they start the vibrations
essential to pitch and pass them along into the cup of the larynx, which
also has shaped itself to the note and where gyration and friction begin
to reinforce the vibrations started by the cords. What is true of the
cup also is true of the resonance-cavities. In other words, the entire
vocal tract, from cords to lips, shapes and reshapes itself with
reference to the tone that is to be produced, and what thus goes on
above the vibrating cords cooperates to produce the effect formerly
attributed to the cords alone.
The fact that the cup of the larynx subtly changes its shape for each
tone produced, makes the hitherto obscure subject of registers of the
voice, which many writers have written around but none about,
perfectly clear. The cup assumes what may be called a generic shape for
each register, and then goes through subtle adjustments of shape for the
different notes within each register. But this is a subject to be taken
up in detail later.
The reader now will understand why at different points in this chapter
I have emphasized the fact that the larynx as a whole and throughout all
its parts is capable of numerous adjustments in shape, and that the same
is true of the resonance-cavities. The vocal tract of an accomplished
singer is capable of as many adjustments as a sensitive face is of
changes in expression. This phenomenon is the vocal tract making ready
to generate, vitalize and emit the tone suggested by the mind--mind
pressing the button, the physical organs of voice-production doing
the rest.