Book: Voice Production in Singing and Speaking

W >> Wesley Mills >> Voice Production in Singing and Speaking




[Illustration: FIG. 33 (Spalteholz). Shows various structures, and
especially well the false and the true vocal bands, with the space
between them (ventricle of Morgagni), but which has no special
function in phonation, unless it acts as a small resonance-chamber,
which is possible. This space is a natural result of the existence of
two pairs of vocal bands in such close proximity.]

[Illustration: FIG. 34 (Spalteholz). Parts have been cut away to
expose to view the whole of the inner surface of the larynx (lined
with mucous membrane). An excellent view of the vocal bands and of the
"ventricle" of the larynx, between them, is afforded.]

When the vocal bands are in action their vibrations are accompanied by
corresponding vibrations of the cartilages of the larynx--a fact of
which any one may convince himself by laying his fingers on the upper
part of the thyroid, especially when a low and powerful tone is
produced. This vibration is not confined to the larynx, but extends to
other parts--_e.g._, the chest itself, for when one speaks or sings a
distinct vibration of the chest walls can be felt, though the extent
to which this is present is very variable in different persons. As an
ascending scale is sung the larynx can be felt (by the fingers) to
rise, and the reverse as the pitch is lowered. This is due partly to
the action of those muscles attached to the larynx which are not
connected with the movements of the vocal bands, and partly to the
influence of the expiratory air-blast. The glottis, partially closed
as it must be in phonation, presents considerable resistance to the
outgoing stream of air, hence the upward movement of the larynx when
it is left free, and not held down by muscular action.

In singing and speaking the larynx should be steadied, otherwise the
"attack," or application of the air-blast to the vocal bands, cannot
be perfect. On the other hand, it is obviously incorrect to attempt to
hold the larynx always in the same position. Holding down this organ
by main force, as in the production of the so-called "straw bass," is
one of the surest methods of producing congestion and consequent
disorders of the vocal organs; and the author wishes to warn all
voice-producers against such unnatural practices. Students of
elocution and young actors often sin in a similar way, and
"clergyman's sore throat" is almost always due to this or some similar
misuse of the vocal organs. One's own sensations and common sense
should never be disregarded, however eminent the teacher who
recommends unphysiological methods.


PRACTICAL CONSIDERATIONS.

When the student has read the above description of the structure and
functions of the larynx, and studied the illustrations well, he will
be prepared to deal with the subject in a practical manner, and
without that it is feared his ideas will remain somewhat hazy.

First of all, he should try to find the parts mentioned in his own
person, following this up by examinations of others, for which purpose
children make good subjects, as they have usually necks that are not
too deeply padded with fat, and they may be easily led to take the
examinations as a sort of fun.

From above downward one feels in the middle line the parts in the
order previously mentioned, beginning with the hyoid bone. One may
learn that the larynx is movable and yielding, a hard structure
covered with softer tissues, but what these are, and much more, can
only be learned by examination of the larynx after it has been removed
from some animal. Every butcher can provide the material for getting a
sound, practical knowledge of the respiratory apparatus. He may be
asked to supply the following:

1. A pig's "pluck"--_i.e._, the "lights," or lungs, with the windpipe
attached. The liver, heart, etc., are not required, though to observe
the relations of the circulatory system--_i.e._, the heart and large
blood-vessels--to the respiratory system will be time well spent.
Unless special instructions are given, the larynx, which the butcher
may term the "weezend," may be lacking or mutilated. It should be
explained that this organ, with a part of the windpipe and the extreme
back part of the tongue, and all below it, are required. For one
sitting this single "pluck" will suffice, as it will serve for a
general examination. The lungs may be dilated by inserting a tube into
the windpipe, tying it in position, and blowing into it with greater
or less force. It should be especially observed how suddenly the lungs
collapse when the breath force is removed, as this illustrates well
their _elasticity_. By cutting through the windpipe lengthwise and
following it downward one learns how numerous are the branches of the
bronchial tree, etc.

For a second sitting one should secure at least two specimens of the
larynx of the pig or sheep, though the former is more like the human,
and so the better on the whole. A case of dissecting instruments is
not essential; a sharp pocket-knife will serve the purpose. In order
that the student may have a clear idea of the cartilages, all the soft
tissues must be cut or scraped away. It is necessary to exercise great
care, or the membranes connecting the cartilages together will be cut
through; and on the other hand, unless the work in the neighborhood of
the arytenoids be cautiously done, these cartilages may be injured,
and it is most important that their swivel-like action and their
relations to the true vocal bands be observed. The glottic chink can
be seen from above or below, and should be observed from both
view-points. Its margins are formed by the true vocal bands.

Then, with the figures before him, the student should endeavor to
isolate each of the muscles described. The muscles can always be
recognized by their red color, but it is to be remembered that those
on the inner surface of the larynx, such as the crico-arytenoid, are
covered with mucous membrane, which after death is very pale. This can
by careful dissection be removed, and if in doing this a small pair of
forceps be employed, the work will be greatly facilitated. One must be
very skilful indeed if he would get all the muscles "out," or well
exposed to view as individuals, on a single specimen. Likely several
will be required before entirely satisfactory results are reached, but
these are well worth all the time and labor required. The action of
the muscles can in some measure be demonstrated by pulling on them in
the direction of their loosest attachment, though it must be confessed
this is much more difficult in the case of most of the muscles of the
larynx than in those of other parts of the body.

Should the specimens be very successfully dissected, it may be worth
while to keep them for future observation, in rather weak alcohol (40
per cent.), in, say, a preserve jar.

All examinations of the vocal bands may leave the observer
disappointed; he may fail to realize, most likely, how such wonderful
results can be accomplished by structures so simple as those he sees
before him. But when the laryngoscope is brought into use, then comes
a revelation. This instrument will be described in the next chapter.


HYGIENE.

Some of the hygienic principles involved have already been referred to
and illustrated, and others follow from the facts already set forth.
It is very important for the voice-user to bear in mind that his
larynx is a part of the respiratory tract, and that the whole of this
region and the entire digestive tract, part of which is common to
both, are lined with mucous membrane. If the nose be affected with
catarrh, the throat does not usually long escape; and if the back of
the mouth cavity (_pharynx_) be disordered, the vocal bands and other
parts of the larynx are almost sure to be involved more or less.

The condition of the stomach is reflexly, if not by direct continuity
through the mucous membrane, expressed in the throat generally; hence
as experience shows, the voice-user cannot exercise too great care as
to what and how much he eats, especially before a public appearance.
He must know himself what best suits him, in this regard, to a degree
that is necessary for few others.

When singing, more blood is sent to the organs used, hence the great
danger of that excess of blood being retained in the parts too long,
as might easily happen from pressure about the neck, etc. It is
scarcely necessary to point out that draughts, cold rooms, etc., will
also determine the blood from the skin inward, and set up that
complicated condition of multiform evils known as "a cold." The
obvious principle of prevention lies in keeping the body, and
especially the neck, shoulders, and chest, warm after using the vocal
organs in any way in public. To hand the singer a wrap after leaving
the platform is always wise, and the judicious friend will see that
conversation is not allowed, much less forced on the possibly
breathless and wearied voice-user--a precaution that is probably more
honored in the breach than in the observance, for in this as in other
cases one's friends are sometimes his worst enemies.


SUMMARY.

The larynx is the most important organ in voice-production, and
consists of cartilages, muscles, the vocal bands, true and false,
membranes and ligaments, folds of mucous membrane, etc. It is situated
between the hyoid (tongue) bone above and the trachea below. The
cartilages are the (1) epiglottis, (2) thyroid, cricoid, arytenoid,
the two small, unimportant cornicula laryngis, or cartilages of
Santorini, surmounting the arytenoids, and the two cuneiform, or
cartilages of Wrisberg, in the folds of mucous membrane on each side
of the arytenoids.

The muscles are attached to the main cartilages. In addition to the
muscles that are concerned with the movements of the vocal bands,
others that hold the larynx in place or raise and lower it are
attached _externally_ to these, especially to the large thyroid
cartilage. The epiglottis, the false vocal cords, the true vocal
cords, and the thyro-arytenoid muscles are attached to the interior
anterior surface of the thyroid in this order from above down.

The false vocal bands have no direct function in phonation. _The whole
larynx, so far as phonation is concerned, may be said to exist for the
true vocal bands._ They are attached close together to the internal
and anterior surface of the thyroid in front and to the lower anterior
angles (vocal processes) of the arytenoids behind. Between the false
vocal bands above and the true vocal bands below there is a cavity
(the ventricle of Morgagni). The false vocal bands are protective, and
approximate closely during coughing, swallowing, etc.

It is very important to note that the arytenoid cartilages move freely
on their base, swivel-like, so that nearly all the changes effected in
the movements and tension of the vocal bands are brought about through
alterations in the position of these cartilages; and this implies that
all the muscles concerned are attached to them. From above down, in
front, the order of structures is as follows:

Hyoid bone.
Membrane.
Thyroid cartilage.
Membrane.
Cricoid cartilage.
Trachea.

The hyoid bone is not a part of the larynx, but from it the larynx is
suspended. The bone itself gives attachment to the muscles of the
tongue. The glottis is the chink between the true vocal bands.

The muscles of the larynx may be divided into the following: (1) Those
that open and those that close the glottis; (2) those which regulate
the tension of the vocal bands. The latter include the (_a_)
crico-thyroids, which tense and elongate them, (_b_) thyro-arytenoids,
which relax and shorten them. The crico-thyroid may be considered the
most important muscle of phonation, because it is so much used and so
effective. By its action the cricoid is pulled up in front and down
behind, so that the arytenoids are drawn back, and thus the vocal
bands tensed and lengthened. The lateral crico-arytenoids and the
thyro-arytenoids have the opposite effect--_i.e._, they relax and
shorten the vocal bands; hence when they come into play a new register
begins. The thyro-arytenoids, attached along the whole length of the
vocal bands externally, have a very important but not well-understood
action in the production of the higher tones, and probably also of the
falsetto.

The whole larynx is lined with mucous membrane, that covering the true
vocal bands being very thin. The false vocal bands are made up chiefly
of mucous membrane; the true vocal bands abound in elastic tissue. The
larynx rises during the production of high tones, and during
phonation its vibrations may be felt, as also those of the chest.


_Practical._

1. Feel in your own person the parts of the larynx, etc., from above
down.

2. Note the vibration of the larynx when a vowel is spoken or sung. A
similar vibration of the chest walls may be felt by the hands laid
over them.

3. Note the change of position of the larynx in singing a scale.

4. Dissect a pig's or sheep's pluck and some specimens of the larynx.

[Illustration: FIG. 35. These three figures illustrate perhaps more
clearly the _action_ of the muscles indicated FIGS. 26-34.

The arrows show the direction of the pull of the muscles. The result
of this action is the new position of the cartilages and vocal bands,
which is shown by red outlines. The muscle is also depicted in red.
The heavier outer rim is to indicate the thyroid cartilage. By
comparing the upper and the lowest figure it will be seen that they
are opposites. Of course, in phonation the vocal bands are never so
much separated as shown in the illustrations. Rather does the lower
figure indicate a case of extreme separation due to a very deep
inspiration. However, these illustrations are merely diagrams meant to
indicate in a general way the manner of the working of parts. For
exact pictures of the vocal bands and related parts, see Chapter
VII.]




CHAPTER VII.

SOUND--THE LARYNGOSCOPE--THE LARYNX RECONSIDERED.


Before discussing our subject further it is desirable that some
attention be given to a few of the fundamental principles of that
department of physics termed _acoustics_, and which deals with the
subject of sound. If the student has the opportunity to study this
subject theoretically and practically, as it is set forth in some good
work on physics, he will have no reason to regret the time spent. A
deep knowledge of the laws of sound is not absolutely essential, or
even highly necessary, for a sufficient understanding of the
principles involved in voice-production. It is, however, all-important
that a few facts and principles be thoroughly grasped.

For those who feel that they have the time for a study of acoustics,
the author would especially recommend Tyndall's work on sound, in
which the subject is treated with wonderful clearness and charm. What
we endeavor now to bring before the reader we have found sufficient
for nearly all the purposes of the voice-user.

An observer on the street, looking at a military band, notices certain
movements of one member of the organization which result in what he
termed the sound of the drum; but a deaf man by his side, though he
sees the movements, hears nothing. This, being analyzed, means that
the movements of the drummer's arm, conveyed through the drumstick to
the membrane of the drum, give rise to movements in it which set up
corresponding movements of the air within the drum, which again cause
movements of the body of the instrument, the whole causing movements
of the external air; and here the purely physical process ends. The
movements other than muscular ones are not readily observed, but
experiments not only prove that they exist, but demonstrate their
nature, even to their exact rate of occurrence, their size, etc. These
movements are termed _vibrations_, and, as has been indicated
previously, they are the sole physical cause of sound. But that the
latter is not due wholly to a physical origin is evident from the fact
that sound for the deaf does not exist. It must, therefore, be a
personal, a subjective experience, and as the sleeping, unconscious
person does not necessarily hear a sound, the process is not wholly a
corporeal or physiological process; it is finally an experience of the
mind, the consciousness, and so is psychological as well as
physiological.

The fact that sound has a physical basis in the vibrations of bodies,
either solid, liquid, or gaseous, may be brought home to one in
various ways. Concussion or shaking of some kind is essential to start
these vibrations. The air is made up of its particles, and one being
moved sets up, inevitably, movements in neighboring particles on all
sides, hence vibrations travel in all directions; which explains why a
sound in the street may be heard by those in every part of the street
not too distant, and also in the upper rooms of the houses and below
in the basements. This is an important fact for the singer or speaker
to bear in mind. His purpose must be to set up vibrations that will
travel with great perfection and rapidity in all directions.

The following experiments of a simple kind will serve to convince
those who may not have given much attention to the subject that sound
is due to movements of some object, which we term the sounding body,
strictly that which starts the vibrations by its own movements or
vibrations.

If a sufficiently flexible band of metal or a stiff piece of whalebone
be fixed at one end in a vice, and then sharply pulled to one side and
suddenly let go, a sound results. The same effect is produced when a
tight cord or small rope is plucked at and then suddenly released. In
each of these cases, if actual movements are not seen, a certain haze
which seems to surround the object may be observed. The same can be
seen when a tuning-fork is set into action by a bow, a blow, etc. In
the case of the fork a graphic tracing (Fig. 36) can be readily taken
on smoked paper, thus demonstrating to the eye that vibrations exist,
that they occur with perfect regularity and with a frequency that can
be measured.

[Illustration: FIG. 36 (Tyndall). Illustrates how the vibrations of a
tuning-fork are registered on a blackened (smoked) glass. In order
that the movements of the fork shall be traced in the form of regular
curves, the surface must be kept moving at a definite regular rate.]

A similar observation can be made in the case of stringed instruments.
If pieces of paper be laid on the strings of a violin, and the bow
then drawn across them, the bits of paper will fly off owing to the
movements--_i.e._, the vibrations--of the strings.

That a force applied at one end of several objects in a line or series
causes an obvious effect at the other end, can be well illustrated in
a simple way. If a number of individuals stand one behind another in a
line, each with his hands laid firmly on the shoulders of the one next
to him, and the person at the end be pushed, the force will be
conveyed through all the intermediate individuals, and cause the
unsupported person at the distant end to move. So is it with the
particles of which the air is composed. The movements begun in the
drum set up by contact corresponding movements or vibrations in the
adjacent air, which ultimately reach the hearing subject's ear,
thereby affect his brain, and are accompanied by that change in
consciousness which he terms "hearing." It will be observed that these
events constitute a chain, and a break anywhere will prevent a sound
being heard; there is then, in fact, no sound.

Sounds are characterized by _pitch_, _volume_, and _quality_.

The _pitch_ is determined by the number of vibrations that reach the
ear within a certain time; the more numerous the sound-waves
(vibrations) in a second, the higher the pitch.

[Illustration: FIG. 37 (Tyndall). Meant to illustrate vibrations. The
impulse communicated by the ball pushed from the hand to all the
intervening ones causes only the last to actually move bodily.]

Animals differ a good deal as to the limits of hearing. Cats hear very
high-pitched sounds, as of mice, that human beings may not notice, and
it is likely that insects hear sounds altogether beyond the limit of
the human ear. But it is wonderful how much human beings differ among
themselves in regard to this matter. It has surprised the author to
find that many persons cannot hear the high-pitched note of certain
birds, as the wax-wing.

The lower limit, speaking generally, is for most persons 16
vibrations, and the highest 38000 vibrations a second, according to
Helmholtz, hence the entire range of the human ear would be fully 11
octaves; but the practical range of musical sounds is within 40 and
4000 vibrations a second--_i.e._, about 7 octaves--and, as is well
known, even this range is beyond the appreciation of most persons,
though as to this much depends on cultivation--attention to the
subject extending over a considerable period of time.

The _volume_, or loudness, of a sound depends on the size of the
vibrations, just as one feels a blow from a large object, other things
being equal, more than from a small one. The ear drum-head is in the
case of a large sound beaten, as it were, more powerfully. The singers
that give us bigness of sound instead of quality belabor our ears, so
to speak; they treat us as persons of mean understanding--dull
intellects; the thing is essentially vulgar.

The _quality_ of a sound is determined by the form of the vibrations.
A sound of good quality is to the ear what a beautiful statue or
picture is to the eye. As will be explained later, the form or quality
depends largely on the shape, etc., of the resonance-chambers above
the vocal bands.

Much discussion has taken place from time to time as to the nature of
the larynx as a musical instrument, some being inclined to regard it
as most closely allied to a stringed instrument, others to a
wind-instrument. It has obviously points of resemblance to both, but
the most recent researches make it clearer than ever that it is
neither one nor the other, strictly speaking, but that it stands in a
class by itself. It is, however, helpful, in considering many
questions, to bear in mind its resemblances to both wind and stringed
instruments. The vocal bands are not wholly free throughout their
length, like the strings of a violin, nor do they bear any great
resemblance to the reed of such an instrument as the clarinet, but as
in the latter the force causing the vibrations is a blast of air. We
have already pointed out that the vocal bands are set into vibration
solely by the _expiratory_ blast of air.


THE LARYNGOSCOPE.

The distinguished physiologist Johannes Mueller demonstrated the
working of the larynx by special experiments. He fixed into the
windpipe a bellows, and showed, in the dead larynx, of course, that
the blast from this source could cause the vocal bands to vibrate and
thus produce sounds, which by varying the strength of the force, etc.,
were made to vary in pitch.

While such experiments indicate the essential principles of a possible
voice-production, as the conditions in life were not and could not be
fully met these results were rather suggestive than demonstrative of
Nature's methods. These investigations served a good purpose, but
they were manifestly inadequate, and this was felt by one thoughtful
vocal teacher so keenly that he pondered much on the subject, in the
hope of finding a method of observing the larynx during actual
phonation. To this distinguished teacher, Manuel Garcia, belongs the
honor of inventing the means of observing the vocal bands in action.
This was accomplished in 1854, and, soon after, Garcia read an account
of his observations to the Royal Society of London; and though much in
this paper required correction by subsequent observations, it remains
to this day the foundation of our knowledge of the action of the
larynx in voice-production.

[Illustration: FIG. 38 (Bosworth). Intended to illustrate the optical
principles involved and the practical method of carrying out
laryngoscopic examination. The dotted lines show the paths of the
light-rays.]

As usually employed, the laryngoscope consists of two mirrors, the
head-mirror, so called because it is usually attached to the forehead
by an elastic band, and the throat-mirror, which is placed in the back
part of the mouth cavity. The purpose of the head-mirror is to reflect
the light that reaches it from a lamp or other source of illumination
into the mouth cavity so perfectly that not only the back of the
mouth, etc., but the larynx itself may be well lighted up; but
inasmuch as this illumination may be accomplished, under favorable
circumstances, by direct sunlight, the head-mirror is, though mostly
indispensable, not an absolutely essential part of the laryngoscope.
There is, indeed, one advantage in the use of direct sunlight, in that
the color of the parts seen remains more nearly normal. Lamplight
tends, because of its yellow color, to make parts seem rather of a
deeper red than they actually are; but this to the practised observer,
always using the same source of illumination, is not a serious
matter--his standards of comparison remain the same. Moreover, this
objection does not apply equally to electric light, now so much used.

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