jaw and accoustic laws

8/11/2019 Jaw and Accoustic Laws

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Stephen F. Austin

P R O V E N A N C E

F lapp ing Jaws and A coustic LawsStephen F A ust in

Journal of Singing, November/Decem ber 2006Volume 63, No. 2, pp . 211-216Copyright C 2006

National Association of Teachers of Singing

provenance (prv -nns) n. Place oforigin, source. [LAT. Provenireto originate ]

ROFESSIONAL JOURNALS OFTEN INCLUDE a letters to the editor sec-

tion in order to give readership a chance to reply, rebut, or perhaps

supplement what someone else has written. Occasionally a single

topic can occupythe attention of readers for several issues, givinginterested parties a chance to iron out their differences in a public forum. One

such exchange took place in the The Musical Times in 1937. Here is a part o

it that will introduce the topic at hand.

A pupil of Garcia s on his teaching

Sir.Twice a w eek for three years I sat in M anuel Garcia's drawing room at Cricklewoodfrom 10:30 a.m. till the time of my own lesson, 1:30, and listened to his teaching. MayI be considered qualified to reply to your correspondent 'J.M.L.' on one or two triflingpoints?

He says ' the mou th was on ly opened su fficiently to admit to the t ip of one finger be-

tween the teeth . ' Seor Garcia insisted on the w idth oftwo fingers as the proper open -ing forAh (all our exercises were sun g onAh . For words of course, one had to adjustthe ape rture, but he never told us to make it as narrow as possible. One of h is favouritecures for a stiff jaw w as to make the studen t hold a l i t tle piece of wood betw een th eteeth wh i le s inging exercises (onAh . 'While you are biting up wards he w ould say,'you cann ot push the jaw down wards. ' He would cut a l i t t le p ost for this pu rpose, withan old knife from a stick of firewood, and it was always qu ite one an d a half incheshigh. The 'tip' of nobody's finger is that width.

To forestall misapprehe nsion 1 add that he n ever intended this app liance to be usedmuch. It was merely to convince students th at they could sing without a rigid Jaw. Theywere then expected to reproduce the se nsat ion in thei r own pract ice . '

The following response appeared in the next issue:

Opening the Mouth in Singing

Sir, Mrs. Ree s-Pedlar's recollections of M anuel G arcia 's teaching caused h er to replyin an interesting letter to some represen tations of mine as to the op ening an d shape ofthe mou th according to the Porpora tradition received through G arcia. M ay I quoteGarcia's words from his 'Art of Singing'?

It is generally believed that the more we op en the m outh, the more eas ily andpowe rfully can sounds be e mitted; but this is quite a m istake. Too large a separa-tion of the jaws tightens th e ph arynx and consequently stops all vibration of the voice,depriving the pharynx of i ts vault-l ike, resonant form. Besides, if the teeth be too

nearly closed, the voice will assume a grating character, somewhat l ike the effect

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Stephen Austin

produced by singing through a comb. By projecting thelips in a funnel shape, the notes become heavy. W hen themouth assumes an oval shape, like that of fish, the voiceis rendered dull and gloomy; the vowels are impe rfectly

articulated, and all but indistinguishable; besides which,the face has a hard, cold, and most unpleasing expression.To open the mouth, the lowe r jaw should be allowed to fallby its own weight, while the corners of the lips retire slightly.This movement, which keeps the lips gently pressed againstthe teeth, opens the mo uth in just proportions and givesit an agreeable form.

Sir Charles Santley, who was for two years a pupil of Nava inMilan and on his return to England had some lessons fromGarcia, writes in his 'Art of Singing' (Macmillan):

The m outh ought not to open more than sufficient to in-

troduce the tip of a finger; if the under-jaw is low ered be-yond what is necessary for this it is impossible to pronouncethe consonants promptly and firmly, as the tongue, teeth,and lips will be too far a part to fulfil their office ... Themost advantageous, and at the same time the mo st pleas-ing and elegant position of the mouth is the approach to asmile:'

Tosi (b. 1683) says in his 'Observations on the Florid Song'1723): The mouth ought to be composed in a manner (if the

sense of the w ords permit it) rather inclined to a smile, thantoo much gravity:'

Isaac Na than (for five years a pupil of Domenico C orn, whowas for seven years a pupil of Porpora) has, in his 'MusurgiaVocalis' 1823), pages on the opening of the mouth. H e begins:Opening the mouth to the fullest extent is by many persons

considered the very acme of perfection: and later says: Exclusiveof external appearances, it is extremely disadvantageous to thevoice to keep the m outh in so open a position; for the fleshysubstance of the cheek must thus necessarily press against theteeth and deaden the sound . . . It is when the mouth is in asmiling form, that the sweetest tones are produced . . It is ad-visable to form the mouth in an easy manner, so as to give duearticulation to every w ord in singing as in speaking.

Gustavo Carulli (b. 1801) in a 'Mthode de chant' 1838),dedicated to and approved by the celebrated and accom plishedFrench tenor D uprez, prints a charming illustration of a m outhin the proper form for singing the first Italian vowel. The teethare mode rately separated and the lips sm iling: the author, inthe text gives the space of separation as some six or eight mu-sic lines, a little less or m ore than half an inch, and draws at-tention to the extension of the m outh at the sides and the rest-ing of the lips on the teeth according to the conformation ofthe mouth, so that the teeth can be seen2

Finally, this response from E. Herbert-Caesari finished

the exchange:

Opening the outh in Singing

Procedures (as quoted by'J. M. L .') such as employingwooden posts:' showing six teeth:' the lips smiling:' a

smiling form of mouth:' m ean absolutely nothing to the stu-

dent seeking the truth; indeed, they mislead because theyteach nothing. The fact of smiling with the lips is assuredlynot the keystone to vocal mechanics. It is worthy of note thatnot one of the quotations given by'J. M . L.' from works ofthe distinguished departed mentions the factor of pitch. Didanybody ever see a great singer produce a high note fortwith a smile on his lips, or with his mouth open no more thansufficient to introduce the tip of a finger as advocated by

Santley? N ow Santley was a fine singer; but like so many greatartists (and teachers), he omitted to amp lify or complete hisideas, and just revealed one aspect of a many-sided procedure.'

To rop or Not to rop

This exchange provides some interesting historical per-

spective on a matter of important consideration: What

should we do concerning the position of the jaw for

singing? What are the implications of a wide or nar-

row space between the teeth? Is there any logic behind

the various positions that teachers and singers take on

the subject?

Unlike the writers quoted above, many of our mem-

bership are engaged in teaching different vocal styles.One of the first things that deserves consideration on

this subject is the fact that different vocal styles may

have different requirements. Does an operatic soprano

follow the same practice as a pop singer? Acknowledging

that a picture is worth a thousand words may be help-

ful to conjure up a few mental images of well known in-

dividuals that most people would recognize as repre-

sentatives of a few of the vocal styles we may deal with.

First, consider the the great operatic soprano Leontyne

Price singing at the top of her range with the mouth gap-

ing wide, but who used much less space in the middle

and low range. There is Lyle Lovett, the country and

western singer with a guitar in hand who sings in a rel-

atively limited pitch range and hardly opens his mouth

at all. Luciano Pavarotti, the great operatic tenor who

sang throughout his range with minimal space between

the teeth (even at the top of his range), especially com-

pared to the prima donna standing next to him. Finally

there are iconic entertainers from the past such as Cab

Galloway from the big band era who sang with a huge

gaping maw throughout his limited range, or the inim-

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rovenance

itable Ethel Merman from the historical merican Theater

tradition, belting throughout her range with mouth wide

open Here we have several different vocal styles, each re-quiring a different sound quality. The question is, does

the mouth opening have anything to do with acquiringthese unique vocal qualities? A brief tutorial in acoustics

and how the vocal instrument works may be of assistance.

ack to as ics

The vocal folds within the larynx are driven into vibra-

tion by an air stream produced by the respiratory sys-

tem. The phonatory cycle consists of the vocal folds

opening and then closing, interrupting and then emit-

ting airflow. The vocal folds are literally blown apart

due to air pressure coming up from the lungs, and theyclose due to the elastic properties of the vocal folds

themselves (and some additional help from negative air

pressures in the glottis). It is the interruption of the air-

flow that produces the sound of the voice. The tone pro-

duced by the larynx is a mere buzz before it is shaped by

the vocal tract. A comparable tone can be produced by

vibrating the two lips as if you were blowing into a trum-

pet mouthpiece, but without the mouthpiece. The vo-

cal folds produce a complex tone, that is, it has acoustic

energy at the fundamental frequency or FO (usually the

pitch that we hear) and a series of partials or over-

tones above it. The partials above the FO are spaced reg-

ularly at frequencies that are integer multiples of the

FO. If the FO is 100 Hertz (Hz), partials occur at 200 Hz,

300 Hz, 400 Hz, and so on. A complex tone is the re-

sult of many simple tones (similar to the sound pro-

duced by a tuning fork) all added together. Light is a

good metaphor for understanding the nature of the

complex tone. We know that white light actually is

made up of many colors by observing what happens

when it is passed through a prism. A complex tone issimilar; when we pass it through an acoustic prism (a

Fourrier transform), we see that a complex tone is many

simple tones occurring at once. We do not usually per-

ceive the individual sounds or partials, but instead our

ears merge them together. We perceive this complex-

ity s t imbre

The manner in which the airflow comes to a halt has

important implications for the quality of sound. If the

vocal folds shut off the airflow suddenly and then re-

main closed for a significant portion of the whole cycle

(over fifty percent), there will be a lot of acoustic en-

ergy in the high partials. We would characterize this

sound as ringing and bright (characteristic of the belt

voice or the operatic sound). If, on the other hand, the

airflow is less suddenly interrupted, or some minimalairflow remains throughout the whole cycle, then we

have a tone where the energy in the upper partials is

much weaker than the first case. The quality of this tone

is likely to be soft, muffled, and much less brilliant. It is

appropriate for many vocal styles (the breathy voice of

Nora Jones comes to mind), but not for the operatic

performer unless used for special effect.

The source is only the beginning. The sound pro-

duced at the vocal folds is a very unattractive buzz when

it leaves the larynx. The vocal tract (the pharynx, oralcavity, and sometimes the nasal cavity) has a profound

effect upon the sound produced by the vocal folds. The

vocal tract has been described as a selective filter which

shapes the sound by favoring some frequencies more

than others.

To begin to understand the filtering process, we of

ten model the air space of the vocal tract as a simple

tube of uniform diameter, open at one end and closed

at the other. I use a mailing tube from the post office as

a teaching tool for this purpose. To demonstrate the

selectivity of the filter, I put one end of the tube up to

my mouth and seal it as best I can. This is the closed

end of the tube. I then sing a long glissando from low

to high and ask the group to s if there is a particular

frequency that becomes louder as I go up and down

the pitch range. There are indeed several points along

the way where the sound emitted out of the open end

of the tube is suddenly much louder than the frequen-

cies above or below that particular pitch. The air space

in the tube is tuned to that particular frequency and

not to others. This is the selective effect of a resonator.A complete explanation of this is beyond the scope of

this brief review, but suffice it to say that if there is

acoustic energy (a partial or harmonic) near the fre-

quency of the resonator, the air space will amplify it

and will make it louder.

The air space in the vocal tract is not exactly like a

mailing tube, but it does behave in a similar fashion.

The movement of the tongue, lips, jaw, larynx, and soft

palate all have an effect upon the shape of the air space

and, as a result, the tuning of the resonances (formants).

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Stephen ustin

The shape of the vocal tract determines the specific fre-

quencies of the resonances. The frequencies of the first

two formants identify the vowels. For [] the first for-

mant (Fl) is about 500 Hz and the second formant(F2)

is about 1500 For I i] Fl is about 35 Hz and F2 is about

2100 Hz, and for [a] they are about 850 Hz and 1200 Hz.

The tongue moves and the resonance frequencies are

changed because the airspace has a different shape. I

teach this concept with the notion of making "vowel

cookies." The larynx produces the raw material, the

vowel dough. Each vowel has a specific resonance shapeand it imposes its shape upon the raw material, and the

result is a unique and distinct acoustic form that we

identify as easily as we can perceive the difference be-

tween a star shaped cookie and a moon shaped one.It is hoped that this brief review of old concepts will

reinforce some basic principles that have been studied

in more depth before. There is one more very impor-

tant new component to this before we can really answer

the question at hand: How wide do we need to drop the

jaw for singing?

Som ething al led Inertive Reactance

Ingo Titze enlightened those in attendance at the 2004

NATS conference in New Orleans about somethingcalled inert ive reactance. He took over an hour to explain

this in some detail. For a more complete review and

some helpful graphs and visual aids, I refer you to his

Power Point presentation that can be viewed on the

website of The National Center for Voice and Speech

at NCVS.org

According to Titze, the vocal tract actually can store

energy and help the vocal folds function under certain

conditions. When levels of inertive reactance are high,

the airflow cuts off more suddenly when the vocal foldsclose. This produces greater energy in the upper par-

tials, a sound that we would describe as bright and rich

in timbre. Dr. Titze described two ways that singers can

take advantage of inertive reactance. The primary means

of increasing levels of inertive reactance are to elongate

and narrow the small air space directly above the vo-

cal folds, called the epilaryngeal tube. This is accom-

plished by lowering the larynx below its resting level or

speech level. (The gesture of lowering the larynx is re-

lated to the concepts of chiaroscuro and voce chiusa th t

I have discussed in previous columns.) To narrow the en-

trance into the epilarynx we learn to "squeeze" the en-

trance into the epilaryngeal tube by contracting the

muscles of the aryepiglottic folds and lowering the

epiglottis. These gestures are commonly observed in

classically trained singers and have been described in

the literature since the time of Garcia's observations

with the laryngeal mirror.

The second means of utilizing inertive reactance in

the vocal tract is through formant tuning. Titze pro-

posed that the level of inertive reactance is highest just

below the frequency of a formant. Years ago we learned

from Johan Sundberg that a soprano can gain as much

as 3 decibels (dB) of intensity by tuning Ficlose to

(just above) the frequency of FO. A doubling of inten-

sity is a 3dB increase, so this is a huge advantage This

is the influence of the resonator adding gain to the par-

tial. It is crucial to appreciate that the frequency of Fl

is influenced tremendously by the position of the jaw

(mouth opening). If you lower the jaw you raise the fre-

quency of Fl, and, conversely, it goes down when the

mouth opening is made smaller. This principle is prac-

tically applied when the pitch that a soprano is singing

is higher than the first vowel formant, which is a com-

mon experience for her. Recall that the range of Fl is

from about 300 Hz for [i] to 85 Hz for [a] with all theother vowels falling in between. We can see that this is

within the common pitch range of the soprano voice,

so the option of formant tuning is almost always there

when she sings above E . She drops her jaw to raise Fl

as the FO goes up. Formant tuning is an important prin-

ciple for two reasons: gain from the resonator and high

levels of inertive reactance.

Denouement

Titze went on to explain another very important prin-ciple that applies to all styles of singing. It has to do

with maintaining certain relationships between the F

and the lowest two partials of the source spectrum. The

quality that we recognize as an operatic soprano singing

above the staff is due to the fact that only the FO is be-

low the frequency of the first vowel formant, an event

that occurs only in the high part of her range. When

an operatic (or classically trained) soprano sings above

the staff and drops her jaw, she raises Fl slightly above

the pitch of the FO. She takes advantage of the boost

from the resonator and she takes advantage of the in-

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rovenance

ertive reactance that helps her vocal folds close firmly

and suddenly giving as much energy as possible into

the sound from the source. That is a specialized ges-

ture in her high voice for a particular vocal quality.

A totally different quality of tone results when thereis more than one partial below the level of Fl. When a

contemporary commercial music (CCM) singer carries

the belt voice (or belt mix) up toward the top of the

staff, he or she will drop the jaw while ascending as well.

But remember we are talking about maybe an octave

lower than the situation for the operatic soprano that

was just discussed. They also drop the jaw to raise the

Fl so that at least the first two partials remain below it

(FO and the second partial). If the second partial goes

above the first formant, the belt quality goes away andthere is a switch in register qualities. This is a partial

explanation for the limited range of this voice. It can

go no higher than the relationship between Fl and the

second partial can be maintained. Recall that the second

partial is twice the frequency of the FO. The Fl for [a]

has the highest frequency for all the vowels at about 850

Hz. For an FO that has a second partial no higher than

850 Hz we are talking about a sung pitch at about 425

Hzabout the frequency of A . This is a common limit

to the trained belt voice. Of course, some singers who

do this style learn to raise that by a considerable amount;

but the important message is that it is not just that they

train the chest register (the vocalis muscle) to be strong

enough to do this, they also learn to modify the vocal

tract so that they raise Fl far above its normal boundaries.

A totally different quality exists when the FO and all

the partials are above the frequency of Fl. Titze described

this as mixed quality. Two examples of this are the

tenor who is singing what we might call the head voice

at or above his passaggio (about F ) and female mid-

dle voice. Many fine singers will use very little mouthopening in this situation. If you watch Pavarotti sing

through this part of his voice and above, he uses sur-

prisingly little mouth opening. The [a] is more open

than the other vowels, which is the case even in the

speech literature for normals (singers are not nor-

mals ), but he never utilizes the kind of space that the

soprano does at the top of her range. There would be no

advantage to do so. A tenor cannot achieve the tuning re-

lationship between FO and Fl that the soprano can be-

cause of the difference in the frequency range of men

and women. The closed vowels [I], [e], and [u] are so

good for training the male voice above the staff because

they have low Fl frequencies and it is relatively easy to

keep the FO and all the partials above Fl. By keeping the

mouth opening small a male voice can lower Fl andkeep this arrangement over his whole top and achieve

the head voice quality. The same gesture works for the

female voice in the middle and low part of her range.

This is what we often observe when we see a female

singing in her middle range. Keeping her mouth open-

ing relatively closed allows her to maintain the middle

voice or Titze's mixed register quality that helps her unify

the registration with the low mechanism and maintain

a real presence in the middle range.

To be sure, all singers do not do the same thing. Anobvious example in the operatic tenor voice was Giuseppe

Di Stefano who tended to use a wide mouth opening at

and above his passaggio The sound was very exciting,

partly because it sounded so raw and even dangerous

it was rather belty in quality. As a young singer Pavarottibecame enamored of Di Stefano's sound. His father (also

a fine singer) cautioned him not to use this technique

because it would be dangerous for him to do so. The

danger was that the top was too open and would stress

the instrument too much. It has been said that Di Stefano

paid a price for his approach, but who can argue with his

success? We can see another example in old films of the

great heldentenor Lauritz Melchior. We see him open-

ing at the top much in the same fashion as Di Stefano.

The passaggio is open and the turn that we expect at

the passaggio is extended higher than normal or never

really happens. For Melchior we can say that his prac-

tice worked for the repertoire he sangand who did it

better? The vocal demands are simply different accord-

ing to the range, style, and timbral expectations.

O N L U S I O N

One of the first things we can do to organize our think-

ing and observations on this matter is to realize that

singers who sing in styles that typically use amplifica-

tion systems are likely to use different strategies than

those who have to sing over large numbers of instru-

ments and other voices. These would include folk singers,

country and western, and other intimate vocal styles.

For them an exaggerated mouth opening serves no pur-

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Stephen ustin

pose. They do not need to take advantage of the acoustic

principles discussed above. What they need most is to

sound natural, and that does not include the kind of ges-

tures that are necessary for the singer of classical music

and other highly energized vocal styles.

On the other hand, for the young operatic and clas-

sical voice in training there are certain articulatory

practices that allow them to optimize the output of

both the source and the filter. One often observes young

women who have not learned to drop their jaw as they

approach their top. The most common flaw that I ob-

serve is that they do exactly the opposite They may

tip their head down, close the mouth and smile and

wonder why they have no high notes.

Consider the young men who have not learned to ac-

cess the high voice. As they approach the secondo pas-

saggio at about E or F., they may try to increase their

mouth opening to a point where it fails. The tone is

white and sounds too open to our ears. Singing the

closed vowels [i], [e], or [u] through the passaggio is

helpful because the first formant is low; we produce

those vowels with a relatively small mouth opening,

keeping the formant as low as possible so that the FO

and all the partials are above it. If the young male singer

would learn to maintain his larynx in a comfortably low

posture and keep his mouth relatively closed at the top,

the head voice could be there waiting to be discovered.

The CCM singer may need to learn to increase jaw

opening starting at a much lower pitch than the classi-

cally trained counterpart. These performers may not

always want the mixed quality in the middle voice, and

instead need to keep the belt quality as they ascend to

the top of their range. This information may be espe-

cially helpful to singers who are attempting to be

crossover artists; each style has a distinct timbre that is

the result of different articulatory gestures.

The fact that we are now coming to a scientific under-

standing of long-standing practice should help us define

techniques that are taught to everybody who is study-

ing a particular vocal style. There is plenty of room for

individuality after certain principles that are "tried and

true" are established in our student singers.

NOT S

Jean Hunter Rees-Pedlar, The Musical Times 78 no. 1130

(April 1937 ): 358.

2 J. M. L., The M usical Tim es 78,no. 113 1 May 1937): 450-451.

3 E. lIerbert-Caesari, The Musical Times 78 no. 1132 (June

1937 ): 551.

Stephen F. Austin, MM, PhD, is a singer, voice teacher, and a trained

scientist. He received a masters degree in vocal performance with the

late Dr. John Large at the University of North Texas, and a PhD in Voice

Science at the University of Iowa with Dr. Ingo Titze. Dr. Austins dis-

sertation was titled The Effect of Sub-glottal Resonance Upon Vibra-

tion of the Vocal Folds. This and other research is published in the

Journal of Voice

Dr. Austin recently joined the faculty of the University of North Texas,

where he is associate professor of voice and voice pedagogy. He is asso-

ciated with the Texas Center for Music and Medicine. The center pro-

vides a unique opportunity for collaboration among musicians physicians

researchers, psychologists, educators, and biomedical engineers.

Dr. Austin has presented recitals, lectures, and workshops across this

country and in Australia and Europe. He is regularly featured on the

faculty of the Annual Symposium: Care of the Professional Voice spon-

sored by The Voice Foundation. He has made presentations to national

conventions of the National Association of Teachers of Singing (NATS),

the American Speech and Hearing Association (ASHA), and the Music

Teachers National Association (MTNA). He has been a featured guest

lecturer at the summer and mid-winter workshops sponsored by

NATS. Dr. Austin has been a regular contributing author to Australian

Voice, the journal of the Australian National Association of Teachers

of Singing, and he serves NATS as the chair of the Voice Science

Advisory Committee and as a member of the editorial board for the

Journal of SinQing He also is a member of the Scientific Advisory

Committee of The Voice Foundation.

Dr. Austin is a successful studio teacher with students singing in opera

houses of Germany and the United States. His students are regular mem-

bers of young artist apprenticeship programs around the country, includ-

ing the Houston Grand Opera Studio, Grass Roots Opera, Des Moines

Metro Opera, Seagle Colony, and many others.

216 OURNAL OF SINGING

jaw and accoustic laws

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