CHAPTER XII

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.

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.