FOURTH PRINCIPLE
_Resonance_ is the _most important factor_ in voice production.
It furnishes to the voice volume and quality, and emphasizes its
loudness. To _rely_ on _resonance_ _rather_ than on _force_ is
essential for producing a big and pleasing voice.
To understand the phenomenon of resonance, it is indispensable
to become acquainted with the few laws of acoustics, which are
most closely related to it. The readers, however, who desire to
get a more complete knowledge of this interesting property of
sound, can refer to any treaties on acoustics where this subject
is widely discussed.
In order to explain what resonance is, we prefer a practical
rather than a scientific illustration, since it is more
advantageous for our purpose.
A common experience—talking into a megaphone—shows how the voice
can become greatly magnified in its characteristics—loudness,
volume, and quality. This is merely the result of a resounding
property furnished by the horn of the megaphone.
If we hold a violin string by its extremities, in tension,
against a brick wall, or an empty space, and strike it, an
almost imperceptible sound develops, given by the vibrations of
the string. If we put the string on an empty case—wooden,
metallic, or of some other material—the sound becomes much
louder and more resonant. The reason is that the amount of air
contained in the empty case vibrates also under the stroke of
the vibrations transmitted by the string, thus magnifying the
vibrations in number and amplitude. The sound, so decidedly
enlarged, is the result of the string only, in so far as the
embryonic element, the vibrations, is concerned; the case is
responsible for its development and enlargement.
The auxiliary function of the megaphone and of the case, with
their characteristic power of magnifying the original vibrations
of the sound constitutes what we call _resonance_.
In the human voice the sounds, as produced by the vocal cords,
are weak and colorless, but when magnified by the resonance
furnished by the laryngopharyngeal and oral tube, plus the
resonance chambers and body cavities, they become larger in
volume, stronger in loudness, and of softer quality.
The laryngopharyngeal cavity and the mouth—a natural horn—as
compared with the megaphone—an artificial horn—act as a
resonating apparatus which magnifies the rudimental vibrations
of the vocal cords into full voice, just as the megaphone makes
the sounds produced into it more voluminous. In both cases the
decided improvement in their original vibrations is due to the
intervention of the magnifying power of resonance.
Scientifically, a tone produced without resonance is a simple
sound; with resonance it becomes a compound or complex sound.
The original sounds produced by the vocal cords are simple, made
up of vibrations of limited sounding power. They become complex
when enriched with the resonating power of the body cavities
which gives them timbre, volume, and loudness. We say _body
cavities_, because we venture to assert that the human body, in
all its cavities, acts as a big resonator for the voice.
Although a chest and masque resonance, originating from the
chest, the antrum and frontal sinuses, are generally admitted,
up to the present time no mention has been made of the body
resonance. Nevertheless if, according to the laws of acoustics,
the vibrations travel in every direction, provided they are not
intercepted by any obstacle, there is no reason why the sounding
waves should stop at the aforementioned cavities of the chest
and masque instead of spreading all over the body, getting the
resonance of all its other cavities—the head, bones, abdomen,
and joints combined.
What usually interferes with the transmission of the sounding
waves from the larynx to the body, confining the radius of their
expansion to the nearest cavities is caused in most cases by a
throaty production which checks the expansion of the voice.
As a result of this false mechanism of voice production even the
amount of resonance given by the nearest cavities is sometimes
obliterated also, as the exaggerated contraction of the throat
prevents the sounds from reaching the resonance chambers. If
this is true of the nearest cavities, it is logical to suppose
that interferences of similar nature are likely to prevent the
vibrations from reaching the more remote sections of the body,
thus hindering the cavities of these sections from making the
valuable contribution of their resonance.
The rigidity of the muscles of the body, for instance, which is
usually the coefficient of a forced mechanism of voice
production, and an instinctive act with many defective singers,
represents a marked physical obstacle to the traveling of the
sound vibrations.
A simple demonstration of this can be obtained by following
closely the phenomenon of resonance in musical instruments. A
piano, for instance, improves its tone merely by being placed on
a wooden platform, in which state its vibrations are not
confined to its strings alone, nor to its case. They travel in
every direction and are transmitted even to the floor and walls
of the room, from which they get other vibrations and resonance,
if the material of which they are composed has resonating power.
Piling many articles of heavy material on the piano and playing
it on a tiled floor, or even on a floor covered with thick
carpets, are sufficient causes for markedly diminishing the
power of its resonance.
All opera houses and theaters are constructed according to the
rules of the physical property of expansion of the vibrations
and their resonating power. Architects take particular pains to
obtain the best acoustics by scientific methods, which guarantee
the free expansion of the sound waves, so they can reach any
empty space within the walls of the building, which are
constructed of such material and in such a shape as to produce
new vibrations, thus increasing their power of resonance.
As for the human instrument, a well-built body, with all its
strong bones and large cavities, undoubtedly furnishes one more
factor of resonance to the resonating power, which should not be
neglected.
There are singers who stand rigidly and heavily while singing,
and their stiffness creates such an obstacle even to the
circulation of the blood, as to be easily discernible in their
spasmodic expressions, and in the congestion of blood in their
faces and necks. These singers undoubtedly deprive the voice of
most of its resonance, because the rigidity of their muscles and
tissues prevents the spreading of the sound vibrations from the
source of their production to the entire body, just as it
prevents the blood from running freely all through the
circulating system.
Several years ago, a prominent London doctor startled the entire
musical world by saying that Caruso possessed musical bones.
A certain newspaper in New York solicited interviews with some
laryngologists to inquire into the possibility of possessing
musical bones. The writer was one of those consulted, and he
found it most difficult to convince the interviewer that,
although there are in truth no musical bones, there is a
possibility of human beings possessing organs made of tissues of
exceptional resonating property, which is dependent, perhaps, on
the quality and constructive essence of the cells from which
they are made.
Indeed, Caruso had no musical bones; but the writer can affirm,
from personal knowledge, that they had a power of resonance
which was startling. In fact, by tapping on his mastoid with a
finger, or, as he did himself, with his ear lobe, a sound was
produced which could be heard at a considerable distance. This
represented merely the exceptional power of resonance of his
bones, which were composed of very fine, compact resounding
matter. This is not at all surprising when we consider that in
some musical instruments the kind of wood from which they are
made has a striking influence on the resonance of the tones
produced, the quality and volume of which, according to
manufacturers, is even related to the number of years of
seasoning of the wood. The hypothesis is naturally suggested
that the compactness of the cells and fibers of certain trees
has the characteristic property of lending to their wood a more
remarkable power or resonance.
Why can not this same possibility exist in the human body? The
resounding property of the masque, head, chest, etc., which are
hollow cavities surrounded by hard compact matter, may be
dependent upon the nature of the cells, which constitute the
constructive substance of the entire frame of the body.
This subject is worthy of a certain scientific consideration,
and should arouse at least sufficient interest for finding out
whether the privilege that certain races possess, of having a
greater number of beautiful voices, is not attached to some
physiological property dependent upon their method of living,
alimentation, climate, etc., which creates a certain difference
in the anatomical structure of the tissues of their bodies.
The soil, sunshine, air, light, etc., which are responsible for
making the fibers of certain trees hardier, drier, and of more
compact matter, better fit for the bodies of musical instruments
than others of soft and spongy nature, raised in marshy, damp
fields, constitute the characteristic conditions which influence
the different growth of those trees. Cannot the same natural
conditions have some influence upon the physiological
development of the human tissues of the inhabitants of certain
regions? By a logical deduction, this should be so. Of course we
are not talking of beautiful voices in reference to their
phonetic and artistic qualities; as for singing, we must not
discard the fact that the more marked aptitude of certain races
for expressing their feelings through singing is due to
psychological influence, such as musical education, environment,
temperament, and, principally, hereditary disposition. We think,
though, that even these traditional racial qualities have at the
bottom a physiological ground, which was generated primarily by
the above-mentioned natural conditions, and evolved gradually
into a psychological form from generation to generation, for
centuries. The temperament of the Latin races, for instance,
especially the Italians, has always been associated with a
certain influence of the mild climate, the bright sunshine, the
clear skies, the volcanos, etc., all such elements which seem to
be responsible for some of their characteristics and natural
dispositions, and have undoubtedly influenced the psychology of
that race.
Therefore, the author’s hypothesis has some scientific and
material foundation. The human body contributes resonance from
all its cavities, and there may exist a difference in the
quantity and the quality of resonance in different persons,
which is dependent upon the constitutional structure and the
development of their tissues, and perhaps upon the origin of
their races.
The voice has three characteristics which are closely allied
with its power of resonance: loudness, timbre or quality, and
volume. From the combination of all of them a strong, beautiful
and resonant voice results.
A recent view, already quoted in this book, gives to the
resonance the power of producing vocal vibrations, besides the
function of magnifying them, a function which is generally
attributed to the vocal cords alone. Thus, according to this
view, the _resonance_ plays a more _important_ rôle, combining
both the power of _magnifying_ and that of _producing_ sound
elements.
The vibrations, by their power of expansion, spread from the
vocal cords into the larynx, where certain resonance is given to
the fundamental sounds by the ventricles of Morgagni. They then
expand through the pharynx, all over the mouth, the resonance
chambers and the entire body. In the resonance chambers more
vibrations are produced by those already traveling from the
larynx, all of them becoming reinforced in their dimensions and
characteristics by the resonating power. This coördinated
strength, resulting from the intensity and amplitude of the
vibrations produced by the vocal cords and by the resonance
chambers, and their magnified resonance, is responsible for the
loudness of the voice, which constitutes the most striking of
its characteristics.
The second characteristic of the voice—the more valuable—is the
timbre or quality, which to most experts signify the same thing.
It is the author’s view that the quality or timbre of the voice
possessing the distinct property of pleasing the ear constitutes
the most prominent characteristic in voice production. It is
worth finding out, therefore, what physical factor gives quality
to the voice.
If we strike a tone on the piano, and let the sound fade
gradually, toward the end of its vibrations, we hear a series of
lighter tones which are perfectly harmonious with the original,
though much higher in pitch. The tone we hear so distinctly at
the beginning, which fades gradually, after a while, is the
_fundamental_ tone, which we are playing. The other sounds,
which are concomitant tones to the fundamental one, are the
so-called _overtones_. The fundamental tone is the lowest in
pitch but much stronger than the others; the overtones are
higher and much softer, and are to the tones what the shadows in
a painting are to the drawing. A well-trained ear can detect the
overtones in voices correctly produced, while in voices produced
by a forced mechanism only the fundamental tone can be heard, or
certain high overtones which do not entirely harmonize with the
fundamental one.
Voices produced with only fundamental tones are poor in quality
and _dry_, lacking the richness in overtones; those in which
incorrect overtones prevail are disagreeable and decidedly
forced.
The quality of the voice can be enriched only through the
abundance of its correct overtones. Because of their importance,
therefore it is of interest to know their position with regard
to the fundamental tones.
The most important overtones are located on the octave, the
twelfth, the fifteenth, and the seventeenth notes of the
fundamental tone. Striking a note on the piano, C below the
staff, for example, the first overtone is C of the next octave;
the second overtone is G above the staff, which is five notes
higher than the first and twelve notes higher than the
fundamental tone. The third overtone is high C above the staff,
fifteen notes higher than the fundamental one; and the fourth
overtone is E, which is seventeen notes higher than the
fundamental tone; and so on.
There are higher overtones, in addition to these, but they are
difficult to detect, except with the aid of Helmholtz
resonators, and are of no help in singing, therefore useless to
discuss.
According to Helmholtz, the overtones which are perceptible to
the ear are those which determine the quality of the voice.
Their presence or absence, whether partial or entire together
with their intensity, decides the particular characteristic of
the organ, whether more or less metallic, and gives to the voice
its distinctive quality.
The overtones are so intimately connected with the fundamental
tone that to change their number or intensity means to change
its quality. In fact, as we said before, a sound without
overtones is soft and sweet, but feeble, small, poor; with the
lower overtones—those classified above—the sound becomes rich,
harmonious and full, still retaining its softness, if all
overtones are produced with the same proportional intensity.
In voice production, when the overtones over the fifth become
more prominent than the fundamental tone, the voice becomes
sharp and disagreeable. Those overtones which should be ignored
are, on the contrary, much developed by the current methods of
singing, based essentially on the force of the breathing
apparatus, which emphasizes, by an exaggerated number of
vibrations, only the highest overtones.
The fullness of the voice is due to the prevailing intensity of
the fundamental tone in relation to its overtones. On the
contrary, the dominating intensity of the overtones over the
fundamental tone causes an emptiness in the voice, which is the
result of thin, small vibrations. The presence, therefore, of
the overtones, and their relative position toward the
fundamental tone, is of capital importance in relation to the
most beautiful of its characteristics—the quality.
The contribution of resonance to the volume of the voice is of
much greater importance than that furnished by the moving
power—the breath, or by the size of the vocal cords—the
producing power.
In musical instruments the volume of the tone is dependent
principally on the size of the case of resonance, which is
related to the amount of air it contains, and to a certain
extent also to the quality of material of which it is made. The
larger and finer the wooden body of a violin, the larger the
volume of its tone. The tone of a violoncello is, in fact,
bigger than that of a violin, due more to its larger case of
resonance than because its strings are thicker, although this
has some bearing also on the volume of the tone. All the
foregoing proves that the size of the vocal cords in relation to
the volume of voice is of much less importance than the amount
of resonance which can be given by the resonating power.
As for the moving power—the breath—it cannot be compared with
the power of resonance. Increasing the power of a violin bow for
the purpose of producing bigger tones cannot compare with the
improvement gained by giving to the violin a Stradivarius body,
so rich in resonance. The strings of the Stradivarius, when put
on another violin, fail to give the same tone, even in the
skillful hands of the greatest virtuoso. All of this proves how
important is the rôle played by the resonance and its physical
properties in all musical instruments.
In the human instrument the volume of the voice is related to
the size of all the cavities of the body, the quality of its
tissues perhaps having some relation too.
The chest and resonance chambers, with the antrum and frontal
sinuses, being the nearest cavities to the source of the voice,
have a more decided influence on its resonance so that those in
whom these organs are well developed have the best conditions
for producing the largest amount of resonance.
The shape of the palate also has a very marked influence on the
resonating power of the voice. A well-arched palate enlarges the
oral space for the sounds, and has the same acoustic property as
the vault of a bridge where even small voices are intensely
magnified by, perhaps, new vibrations created by the vault
itself. For the same reason the tongue has some effect on the
resonance.
Titta Ruffo, the world-famous baritone, has told the writer of a
singer whose voice was mediocre, but who could shape his tongue
in a decidedly concave position like a cradle, thus creating a
larger oral cavity for the resonance of his voice, with
remarkable results. Evidently the instinctive conception of that
singer was correct, for, by shaping his tongue in this position,
enlarging the space, he created more resonance for his voice.
This should serve as warning to the many singers who hold their
tongues in a stiff and contracted position, thus abolishing most
of the mouth’s precious space. The illustration in Fig. 11 gives
practical evidence of how the tongue should be shaped to create
the largest space and resonance in the oral cavity.
[Illustration:
FIG. 11.—THE TONGUE IN COMPLETE RELAXATION ON THE FLOOR OF THE
MOUTH, AND IN A CONCAVE POSITION TO CREATE A LARGER SPACE IN THE
ORAL CAVITY
]
All the author’s efforts in the foregoing pages tend to show
that Resonance is the most important factor in voice production.
To rely on _resonance_, and not on _force_, must be the aim of
every singer; and to remember that the largest amount of
resonance can be obtained only by the complete relaxation of the
vocal organs, must be the fundamental rule of any method of
voice culture. The methods in vogue, which base their foundation
on breath, that is, on force, are as erroneous as dangerous.