A study of intra-laryngeal activity during production of voice in normal and falsetto registers

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NAME AND ADDRESS

DATE

NORTHWESTERN UNIVERSITY

A STUDY OF INTRA-LARYNGEAL ACTIVITY DURING PRODUCTION OF VOICE IN NORMAL AND FALSETTO REGISTERS A DISSERTATION SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFILLMENT OF THE REQUIREMENTS for the degree DOCTOR OF PHILOSOPHY Field of Speech

By PERRY EMANUEL BAISLER Evanston, Illinois August, 1950

ProQuest Number: 10060859

All rights re s e rv e d IN FO R M A TIO N TO ALL USERS The q u a lity o f this r e p ro d u c tio n is d e p e n d e n t u p o n t h e q u a lity o f t h e c o p y s u b m itte d . In th e unlikely e v e n t t h a t th e a u th o r d id n o t s e n d a c o m p le t e m a n u s c rip t a n d th e r e a re missing p a g e s , th e s e will b e n o te d . Also, if m a te ria l h a d to b e r e m o v e d , a n o te will in d ic a te th e d e le tio n .

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TABLE OP CONTENTS

Page LIST OF TABLES LIST O P ILLUSTRATIONS INTRODUCTION AND STATEMENT OF

THE

P R O B L E M .........

1

Origin and Significance of the Problem Significance of Particular Method Used Statement of Purpose A P P A R A T U S ...............................................

7

Photographic Equipment Sound Recording Analytic Equipment Arrangement of Apparatus P R O C E D U R E ........................... * .................... 14 General Plan of the Experimental Procedure Preparatory Procedure Taking the Pictures Examining the Film Analyzing the Sound Limitations of the Method PRESENTATION AND DISCUSSION OF R E S U L T S .................. 27 Vibratory Patterns in Terms of Glottal Length Vibratory Patterns in Terms of Glottal Width Vibratory Patterns in Terms of Glottal Area Combined Patterns of Vibration The Apparent Thickness of the Folds Supra-glottal Conformations The Glide between Normal and Falsetto Registers Results of Sound Analysis SUMMARY AND C O N C L U S I O N S ..................................84 Review of the Problem Summary of Results Conclusions Implications APPENDIX A*

Data from Glottal Measurements . * • * •

APPENDIX B.

Sound Analysis D a t a ...........

BIBLIOGRAPHY

93 102 108

t;,e i 7 6 3

LIST OF TABLES Table I. II# III. IV. V. VI. VII.

Page Elements of the Experimental Conditions . . . . Percentage of Cycle Occupied by "Closed,* "Opening" and "Closing" Phases. . ................ Glottal Width Measurements - Conditions I through IV - Subject A . .............

36 71 94

Glottal Length Measurements - Conditions I through IV - Subject A ........................... 95 Glottal Length-to-width Ratios - Conditions I through IV - Subject A .............

96

Glottal Area Measurements - Conditions I through IV - Subject A. ......................... 97 Glottal Width Measurements - Conditions I through IV - Subject B. .................

98

VIII.

Glottal Length Measurements - Conditions I through IV - Subject B ........................... 99

IX.

Glottal Length-to-width Ratios - Conditions I through IV - Subject B .......................... 100

X.

Glottal Area Measurements - Conditions I through IV - Subject B .................

101

LIST OF ILLUSTRATIONS Figure 1. 2.

Page Schematic Arrangement of Photographic Apparatus • • • • . . . . . .

10

Set-up for Viewing and Tracing Individual ........................ Frames.

12

3.

Typical "Open” Frames - Conditions I to IV*

. 22

4.

Before and after Transition - Condition V .

* 23

5.

Tracings of Laryngeal Image - Subject A Condition I . . . * . * . . .

6.

28

Tracings of Laryngeal Images - Subject A Conditions II and I I I .......................

29

7.

Tracings of Laryngeal Images - Subject A Condition I V ...................................... 30

8.

Tracings of Laryngeal Image - Subject B Condition I .........................

9. 10. 11. 12. 13. 14. 15. 16. 17.

3

Tracings of Laryngeal Images - Subject B Conditions II and I I I ........................... 32 Tracings of Laryngeal Images - Subject B Condition I V .........................

3

Typical Visible Conformations of Supraglottal Structures. ..................

34

Length of Glottis in Successive Frames of Cycle - Subject A - Conditions I and IV . •

. 37

Length of Glottis in Successive Frames of Cycle - Subject A - Conditions II and III •

. 38

Length of Glottis in Successive Frames of Cycle - Subject B - Conditions I and IV . . .

42

Length of Glottis in Successive Frames of Cycle - Subject B - Conditions II and III .

. 43

Width of Glottis in Successive Frames of Cycle - Subject A - Conditions I and IV ♦ ♦

. 47

Width of Glottis in Successive Frames of Cycle - Subject A - Conditions II and III ♦

. 48

Page

Figure 18* 19* 20* 21* 22* 23. 24. 25* 26* 27.

Width of Glottis in Successive Frames of Cycle - Subject B - Conditions I and IV . * .

52

Width of Glottis in Successive Frames of Cycle - Subject B - Conditions II and III

.*

53

Area of Cycle -

Glottis In Successive Frames of Subject A - Conditions I and IV .

* •

56

Area of Cycle -

Glottis In Successive Frames of Subject A - Conditions II and III

*•

57

Area of Cycle -

Glottis in Successive Frames of Subject B - Conditions I and IV •

* .

60

Area of Cycle -

Glottis in Successive Frames of Subject B - Conditions II and III

* •

61

Variations in Glottal Length***to-width Ratios - Subject A * ...........................

63

Variations in Glottal Length-to-width Ratios ~ Subject B .............................

64

Proportional Representation of Vibrational Factors - Subject B - Conditions II and III .

66

Spectra of Sounds in Normal Register Subject A ...........

103

28.

Spectra of Sounds in Falsetto Register Subject A ........................................ 104

29.

Spectra of Sounds in Normal Register Subject B .........................................105

30.

Spectra of Sounds in Falsetto Register Subject B ........................

31.

106

Calibration Curve for Magnetic Tape R ec o r d e r ........................................... 107

A STUDY O F INTRA-LARYNGEAL ACTIVITY DURING PRODUCTION OF VOICE IN NORMAL AND FALSETTO REGISTERS^Perry E. Balsler Northwestern University

INTRODUCTION AND STATEMENT OP PROBLEM It may be safe to assume that "registers* In the human voice have been discussed as long as students have been interested In the improvement of singing and speaking. It was not until about the middle of the last century, how­ ever, that definite attempts to describe the phenomenon began to appear in the literature.

About that time, it Is

reported, Manuel Garcia defined a register as a series of consecutive vocal notes which the musical ear can distin­ guish from an immediately following series of notes, such that the change in passing from one series to the other may also be detected (15).

More recently Luchsinger offers an

almost identical definition which he attributes to Nadolecsny (6)*

Almost all authorities agree that there can

be easily distinguished in most voices at least two such "series"--a "lower" and a "higher," the latter often being called "falsetto." •^Grateful acknowledgement Is made of the assistance of Dr. Paul Moore, director of this study.

1

2 W ith the clearer recognition of the auditory nature of registers came attempts to explain them in terms of characteristic alterations in the functioning of the vocal mechanism-

The frequent use of the terms "head-11 and

"chest register’* reflects the early tendency to make the differentiation a matter of a change in the relative use of these two parts of the body, i.e., to make resonance ad-* justments the chief explanatory principle*

On the other

hand, as modern methods of investigation have made the larynx more accessible for observation, there has been a strong tendency to seek at least part of the answer in the altered function of the laryngeal mechanism (1, 4, 6, 31, and others).

It is in the latter tradition that the present

study was undertaken. An early survey of the field revealed a considerable lack of agreement as to the number of registers In the human voice.

Relatively authoritative opinion has placed

the count all the w a y from one (7) to six (6).

In a pre­

liminary attempt to define the scope of the current prob­ lem the writer secured the cooperation of 64 students in beginning speech classes at the University of Washington. Each subject was asked to glide up the scale while humming from his lowest note to the highest one he could reach with­ out discomfort.

Of the total number only four failed to

exhibit a "break” that could be clearly detected by the ob­ server and six showed two equally obvious breaks.

Of the

four whose voices seemed to continue in an uninterrupted

3 fashion, two had had considerable training in singing, and a third had an extremely limited r a n g e - w e l l under one oc­ tave*

When asked to report on their subjective reactions

52 (including one of those with vocal training) said they "felt" one major readjustment of the vocal apparatus, while eight reported two such sensations# Obviously results from a rough procedure of this kind were not to be considered conclusive, but since they were not at variance with the opinion of Curry (1, p# 66) and others that the average voice Is characterized b y two main registers, it was decided to limit the present inves­ tigation accordingly# The names most commonly applied in this country to these two major divisions of the voice are "normal" and "falsetto#"

Some writers,

including Husson (23), have fol­

lowed the practice of referring to the upper register as "the falsetto In men and the fhead* voice in women," but since they make no further distinction between the two, It appeared to be a useless elaboration of terminology# It might be well to point out here that register is closely associated with, and hence frequently confused with, pitch#

Under normal circumstances a change of register is

always accompanied by a change in pitch.

Yet It seems ob­

vious that the former is essentially a quality phenomenon. This is so b y definition, which Implies a "sameness" to the tones within a given register.

In other words, the difference

4 between normal and falsetto register is not a matter of pitch; otherwise the distinction would he between successive tones, not between successive series of tones.

That it is

not a matter of loudness is suggested by the fact that the latter may be varied completely independently within either register.

It is equally obvious that It is not a matter of

duration— all of which leads back to the earlier statement that register is primarily a matter of quality. 0ne additional point needs to be made clear at this time.

Registers tend to overlap (6, 14, 22, and others)-*

that Is, as the voice moves up the pitch scale the break, or transition, is apt to be higher than when the voice ap­ proaches the critical area from above. Origin and significance of the problem.

The modern

student of voice, whether he is primarily Interested In vocal training or in the scientific knowledge upon which such training Is presumably based, Is continually confronted with the problem of "voice register."

Pew present-day text­

books dealing with either the singing or the speaking voice— fail to devote at least some space to the nature and Impor­ tance of this matter. writer*s opinion,

Much of this material Is, In the

superficial, and some of it appears to be

inconsistent and hence at least partially inaccurate.

Con­

fessions of a general lack of basic information regarding the phenomenon are numerous.*

Some authorities attempt to

*4s.g., cf. Metzger (28, p. 109).

5 dispose of the problem by such statements as:

"Indeed the

concept of registers is probably useless, except perhaps to explain falsetto voice. all in this connection.

Again, it may be least useful of • •

(3, p. 194).

Others have

elaborated quite definite theories of register which are ap­ parently based on little or no experimental evidence.

Most

of the evidence that Is available has been based upon stro­ boscopic observation.

The disadvantages of this method of

studying vocal fold activity have been pointed out by Moore (30). Significance of the particular method u s e d .

The

scarcity of our knowledge concerning the relationships be­ tween laryngeal function and register is due in part at least to the difficulty in viewing and measuring the rapid movements within the larynx during phonation.

Indirect

laryngoscopy along with normal speed photography has yielded some knowledge of gross intralaryngeal activity, and more recently high-speed motion picture photography has been adapted for study of the vibratory action of the vocal folds. This technique has been and is being used In the study of pitch and intensity changes.

In 1937 a film (16) was pre­

sented before the American Acoustical Society (21) which showed, more or less incidentally, a few short bursts of falsetto at high speed, but the writer has been unable to find evidence that this particular method of investigation •^Por an account of the problems and progress in the field of laryngeal Investigation see Moore (29) and Metzger (28).

6 has been focused directly on the problem of vocal register# It is felt that this technique, together with the constantly Improving methods In X-ray photography, m a y eventually lead to the solution of many of the current problems relating to voice production# Statement of purpose#

This investigation was de­

signed to study and describe the activity within the larynx during the production of voice in each of the two registers, normal and falsetto# More specifically,

it was an attempt to find answers

to such questions as the following: 1#

Is there a difference between the registers in the patterns of vocal fold activity as determined by: a) the changing length and width of the glottis during typical cycles of vibration? b) the variations of the glottal shape as defined by the relationship of length to width? c) the pattern of area change? d) the length of each phase of the vibration cycle (I#e#, closed, opening, and closing phase)? e) the point of initiation of the opening on the glottal axis and the course of its extension? f) the apparent mass of the folds involved in the vibration?

2.

Is there a difference in the adjustment of the false folds and other supra-glottal structures of the larynx between the two registers?

3#

If such differences are observed, do they appear to be consistent from person to person?

4.

What type of laryngeal adjustment occurs at the moment of transition between registers? As has been suggested, answers to these questions

were sought in this study primarily through the use of high­ speed motion picture photography#

The apparatus employed

made It possible to get pictures of the larynx in action at

7 speeds in excess of 4000 frames per second#

When the film

was projected at normal speed (16 frames per second) the rapid laryngeal movements were ”slowed dow n ” to less than 1/250 of their actual rate, and more significant qualitative observations could be made than would be possible through direct viewing or through ordinary photography*

It also

permitted a careful analysis of consecutive film frames, during which measurements could be made of cycles typical of the various experimental conditions*

Supplementary in­

formation was obtained by subjecting the vowel sounds re­ corded during photography to a physical analysis* It should be recognised here at the outset that the basic technique to be described in more detail later has certain limitations which will be outlined at that time* Because of these the answers obtained in this research must be looked upon as suggestive rather than conclusive*

APPARATUS In the accumulation of data for the present study a number of different pieces of equipment were used. may be classified roughly Into three groups: graphic equipment,

These

(1) the photo­

(2) the sound recording apparatus, and

(3) the analysis equipment.

A brief description of the

various pieces follows* Photographic equipment*

The camera used*** was a

■^The writer wishes to acknowledge with thanks that

8 Western Electric Fastax.

This is a precision-built research

instrument developed at the Bell Telephone Laboratories and is capable of exposing motion picture film at a rate in ex­ cess of 4000 frames per second (20)* The film used was Oine-Kodak Super-XX, 16 mm., No. 355.

This particular type has twice the number of sprocket-

wheel perforations as in the ordinary 16 mm. film, and while it was found that film with standard perforation could be used with some success in an emergency, the risk of film damage is excessive, and the practice is not recommended. The lens with which the camera came equipped proved to be unsuitable for the short-focus work required.

It was

found that by mounting a four inch lens on an adapter which moved it out an additional one-half inch from the camera prism, pictures of satisfactory size could be obtained.

The

lens used was a lumenized Cine-Kodak Anastigmat, 102 mm., f./2.7. Illumination was obtained from a 5000 watt incan­ descent lamp.

Since a source of this kind generates a great

deal pf heat, it was necessary to cool the light to avoid burning the subject.

This cooling was accomplished by

passing the light rays through approximately ten Inches of water, contained In a cylindrical water cell eight Inches the camera employed in this research was the property of the Armour Research Foundation of the Illinois Institute of Tech­ nology. He is also grateful to Messrs. Betz and Perrine of their staff, who not only cooperated In making it available but also offered valuable suggestions as to its use.

9 In diameter.

A lens then converged the rays onto an oblique,

front-surfaced mirror which was located so as to turn the light axis approximately 90 degrees and direct it Into the mouth of the subject.

A guttural mirror (also front-surfaced)

located in the oro-pharynx reflected this light down into the larynx (see Fig. 1).

Since it was neither necessary nor

desirable to have the lamp burning at maximum intensity all the time, a variable transformer was employed to regulate the voltage to the lamp.

A 120 volt Powerstat, type 11D56

(Superior Electric Company) was used for this purpose. Sound recording.

A magnetic tape recorder was em­

ployed to record the phonated sounds. Brush Sound Mirror, Model BK-401.

The type used was a

Sound was put into the

recorder through a Turner Dynamic microphone, Model TJ93. Analytic equipment.

The analysis of the film and

the recorded sounds required distinct types of apparatus. 1.

Film analysis.

Standard 16 ram. projectors were

used for frequent screening of the film, during which quali­ tative observations were made.

For detailed frame to frame

analysis, however, a special viewing device was set up (see Fig. 2).

A Keystone projector, Model D12, was mounted on a

table with the lens directed at a convenient angle.

An op­

tical flat, front-surfaced by evaporation, was then mounted at such an angle as to direct the light from the projector almost directly downward at the other end of the table.

The

angle of the tracing table (E, Fig. 2) was then adjusted so that no distortion of a projected image occurred.

Finally,

10

F

A B C D E F

Fi g. I

CAMERA O B L I Q U E M I RR O R L I GHT L E N S WATER C E L L LAMP GUTTURAL MI R R O R

S C H E M A T I C A R R A N G E M E N T OF

PHOTOGRAPHIC

APPARATUS

XI the table (E) was raised to a height which gave an exactly five to one enlargement of the laryngeal image on the film. It was found necessary to construct a supplementary table (D) to meet the above conditions for the female subject, whose shorter pharynx brought her larynx somewhat closer to the camera during photography* The enlargement ratio in each case was determined as follows.

Immediately after a series of pictures was

taken, the subject withdrew and a millimeter scale was placed at the approximate level of the larynx and within the photographic field as viewed through the camera*

The

scale was moved up and down and then fixed and photographed at the point where it came into sharpest focus*

By project

ting this photographed scale the amount of enlargement could be readily determined. After preliminary experimentation with this viewing apparatus, it was found advisable to erect a screen (B, Fig. 2), with a hole in it just large enough to admit the projec­ ted beam, between projector and work tables*

This prevented

’’fading" of the image due to light leakage from the projector to the observerfs eyes* 2*

Sound analysis*

The major piece of equipment in

this group was a General Radio Sound Analyzer, Type 760.^However, the procedure also employed (see next section of the paper) a vacuum tube voltmeter (Hewlett-Packard, Model ^This Instrument was borrowed from the N.TJ. Techno­ logical Institute through the courtesy of Dr. C* J. Overbeck*

12

Fig.2

A

PROJECTOR

B C 0 E

SCREEN OPTICAL VIEWING VIEWING

SET-UP

FOR

WI TH OP E N I N G TO PASS

FLAT LEVEL LEVEL

VIEWING

FRONT

PROJECTION

SU R F A C E D

FOR S U B J E C T FOR S U B J E C T

AND

TRACING

B A

INDIVIDUAL

FRAMES

13 400A) and an audio-oscillator

(Hewlett-Packard, Model 200B).

Arrangement of apparatus.

The basic relationship of

camera and light systems is illustrated in Fig. 1, but a few additional details should be mentioned.

It was found most

satisfactory to arrange these .two systems so that their axes were in the same horizontal plane and formed an angle of approximately 90 degrees.

Numerous light meter tests indi­

cated that the most efficient Illumination at what would be (during photography) the level of the glottis^- was secured when the following relationships obtained:

distance from

the center of the lamp filament (which had been rotated slightly to give the effect of some narrowing and greater concentration at the light source) to the center of the convex surface of the lens--18 inches, and to the center of the oblique mirror— 22 Inches; distance from this latter point to the center of the guttural mirror--12.5 inches. The camera, oblique mirror and guttural mirror were all mounted on a rigid table some 42 inches high, and the table was securely anchored to the floor.

The oval hole in

the oblique mirror was approximately three Inches wide and two inches high.

The lamp, water cell and lens, together

with the Powerstat, were mounted as a separate unit. Finally, the microphone of the sound system was mounted Immediately to one side of the table

(but not touch­

ing it), on a level with the guttural mirror and seven Inches ^The small variation In glottal level between the subjects was found not to be significant here.

14 from

it along a30 degree radius.

It remained in this posi­

tion

during the filming of all conditions.

PROCEDURE As has been suggested in the earlier sections of the paper, the basic technique employed in this study was the use o f high-speed cinematography to record the move­ ments within the larynx during the production of voice in normal and falsetto registers, and the careful observation and analysis of the resulting film to determine the compara­ tive patterns of action.

To supplement this method, and as

a possible check on the accuracy of the above observations, a physical analysis of the sounds produced by the voice during filming was also done. General take

plan of the experimental procedure.'*'

First,

motion-pictures at approximately 4000 frames per second

of the larynx of each of two adult subjects producing the vowel

at constant intensity during the following five

conditions:

(I) at a pitch well within the normal register,

(II) at a pitch close to the top of the normal register,

(III)

at approximately the same pitch as In (II) above but in the falsetto register,

(IV) at a pitch well within the falsetto,

(V) on a glide between normal and falsetto using the pitches To facilitate the frequent references to the experi­ mental conditions that will be necessary, the broad outlines of the design are summarized In Table I.

15 of (I) and (IV) as terminal levels*

Second, make qualitative

observations during repeated projections of the film at nor­ mal speed,

i*e*, when the motion of the laryngeal structures

had been slowed down at a ratio of about 250 to one*

Third,

select appropriate cycles from the different conditions and make measurements of structure relationships from frame to frame * Preparatory procedure*

Two adult subjects were se­

lected primarily on the basia of the criteria suggested earlier In this section.

.

While the fact that one of the

subjects was a woman was not particularly advantageous as far as the major purpose of this study was concerned,

it was

felt that her very unusual ability to expose the vocal folds for photography under a variety of conditions would make a distinct contribution*

Trials were made to determine the

approximate ranges of the two voices, and for each, the average level at which the break occurred between the two registers.

Ihe subjects were then tested as to their ability

to perform the five conditions of the experiment (see p* 14 and above).

At first It was noted that both subjects

(one

in particular) would occasionally slip into the wrong regis­ ter on Conditions II and III.

Since this was an obviously

crucial point In procedure, It was a matter of some concern and was given special attention.

It was discovered that If

the subject approached Condition II by phonating up the scale, and Condition III by singing down from higher in the falsetto, there were no "slip-overs.”

When this was done

16 the two tones were consistently identified with the proper register by all three observers, one of whom had had con­ siderable musical training. The general alignment and adjustment of the equip­ ment was accomplished by repeated checks with each subject In the "photographic position."

The camera was moved back

and forth to determine the position in which the largest possible laryngeal image was presented In the center of the viewer, and In which at the same time only a slight adjust­ ment of the lens was necessary to bring the glottis of each subject Into the sharpest focus. to the table at this point.

It was fastened securely

"Dry runs"

(camera Inoperative)

were conducted to determine the most convenient setting for t

the volume control on the recorder, which was then fixed at that position.

A full fledged trial run (100 feet of film)

demonstrated that the camera viewer could not be depended upon for sufficiently sharp focus under the conditions of the experiment.

More adequate focus was obtained by devising

a viewing screen that would fit on the sprocket wheel of the camera and then adjusting the focus before the camera was loaded. The adjustment and calibration of certain supplementary pieces of apparatus are described later In this section. Taking the pictures.

The specific goal of each photo­

graphic session was to obtain clear pictures of the experi­ mental condition, with faithful performance of all Its spe­ cifications but without excessive fatigue on the part of the

17 subject.

To this end a routine was set up composed of six

fairly distinct steps.

In step 1 the subject received care­

ful instructions as to the exact requirements of the condi­ tion under consideration.

He was then given the pitch from

the audio-oscillator and allowed to practice,

^hen In the

opinion of three observers he was able to reproduce the con­ dition easily and without error for six consecutive times, he was Instructed to rest while the next step was taken. Step 2 consisted of a final check on the equipment.

The os­

cillator was checked against a tuning fork, and the lamp, camera, and recorder were tried out to see that they were functioning properly.

In step 3 the subject practiced moving

up over the mirror**' and adjusting himself so that his laryn­ geal Image was properly framed in the viewer of the camera. This was done with the help of Instructions from the operator apd with aid of a reflecting glass which together enabled the subject to identify the correct position.^

During this

step final adjustment of the focus was made b y the method described earlier in this section of the paper.

In step 4

the subject rested while the camera was loaded.

During this

process a hole was cut about one and one-half feet from the end of the film and this section was placed over a hole in •*-To prevent clouding it was necessary to warm this periodically to approximately body temperature by means of a portable heater. ^This step proved difficult and tiring in preparation for one or two of the first films, and it was deemed advisable to give up and postpone work until the following day.

i

18 the sprocket wheel, which in turn was lined up through the prism with the axis of the camera lens system.

This proce­

dure enabled the operator to assist and check the subject in the proper framing of the laryngeal image during the last two steps.

Step 5 consisted of a complete "dress rehearsal"

for photographing the condition except that the camera and recorder were not in operation.

If the subject did not

come into position easily and meet the vocal requirements of pitch, Intensity and register by his second attempt, a halt was

called, and one or more of the earlier steps was

repeated.

Step 6*

During the brief Interval that the gut­

tural mirror was being re-heated the recorder was started and the oscillator tone was fed in from the ear-phone through the microphone.

The earphone was then replaced on the sub­

j e c t s head, and he moved into position while the light was turned up full.

He then went through a final trial, and if

not stopped by a prearranged signal, he tapped his foot, took a breath, and began to phonate. immediately,

The camera was started

completing the exposure of its 100 feet of film

In about ij seconds, and the subject continued to phonate as long as he could comfortably after the camera had stopped. This sequence was repeated for both subjects on all five conditions, thus exposing in all a total of 1000 feet of film. Examining the film, 1,

Observation during projection at normal speed.

The "ultra slow-motion" effect thus achieved enabled the

19 observer to determine patterns of activity that were much too fast for the naked eye to catch#

Notes on the patterns for

all conditions were recorded# and these observations were checked during repeated showings at different times# 2#

Analysis of cycles#

It was felt that a more

detailed study of Individual cycles from the various condi­ tions would add to our knowledge of the patterning involved and make for a more accurate differential comparison of normal and falsetto registers# most fruitful analysis

It appeared that for the

(of the high-pitched falsetto action

especially) one of the most important considerations was to get as many frames as possible in the cycles selected#

For

a given pitch this number naturally varied with the speed of the camera#

Since it was found that the camera was con­

tinuing to accelerate slightly even after reaching its rated speed in the first half of its run, it was decided to select the cycles from the last 12 feet of the films--thus gaining the advantage of what was practically the cam e r a fs greatest speed and at the same time avoiding the last few feet, which in many instances appeared "light-struck.” An exception to this rule was made in the procedure applied to Condition ¥, i.e., the glide from normal to fal­ setto, which presented a special problem.

The attempt to

control intensity during photography of this condition had been completely unsuccessful In the case of both subjects, and by the very nature of the condition the pitch was con­ stantly changing#

Moreover, the element of crucial interest

20 in these films, i.e., the transition between registers, was obviously somewhere In the earlier cycles.

It was finally

decided to determine by repeated Inspection the essential activity patterns they revealed, and to proceed with a quail tative description of those features. As Individual frames of these cycles were projected In sequence it was possible to observe more closely and to quantify by measurement some of the major factors that con­ stituted the action pattern of the laryngeal structures during phonation In a given register.

A projection device

was set up which enlarged the laryngeal Image on the film until it was exactly 25 times the actual size of the larynx under consideration. ratus.)

(See Fig. 2 and the section on appa­

Various attempts to make measurements of the Image

thus projected demonstrated that the most efficient method was to make careful tracings of each projected frame and then make the measurements from the tracing.*** to 11.)

(See Figs. 5

It will be obvious from consulting the accompanying

figures that, because of shadows created in the larynx dur­ ing photography, no method of measuring such pictures can be considered rigidly exact, but for the comparative pur­ poses of a study of this kind the technique described has been shown to be sufficiently accurate (17, pp. 33 ff.). In a number of films the subjects were unable to \

keep the epiglottis from obscuring the anterior ends of the ^Brackett reports the same experience in a similar study completed In 1947 (17, pp. 23 ff.).

21 folds and, during some of the frames, the posterior end of the glottal opening (see Pig* 3)*

In the tracing the lines

representing these structures were continued to an imaginary terminal point under the shadow of the epiglottis 5 and 8)*

(see Pigs.

This procedure was felt to be justified because

the observable portions gave a pretty good indication of what was occurring in the hidden portion, and because the w r i t e r ’s frequent observation of these two larynges under more favorable conditions enabled him to make such estimates with a fair degree of accuracy.

In any case, the slight ad­

ditional error that was undoubtedly involved in this practice was felt to be much less than if the obscured areas had been ignored entirely. Further study of the film indicated that the factors most significant in analyzing the vibratory patterns of the vocal folds were: (2) Its length,

(1) the changing area of the glottis,

(3) its width,

(4) the point at which It

first appeared to open and the direction in which the open­ ing seemed to move, and (5) the time relationship among Its "closed,” "opening and "closing" phases.

In addition it was

felt that the apparent length of the true folds and the area between the false folds were to some extent indices of the action of the supra-glottal structures.

Consequently careful

measurements of all these elements were undertaken.

An engi-

ft

n e e r ’s steel millimeter rule and of a polar planimeter were used for this purpose.

I

22

SU B JEC T - A

SUBJECT - B

NORMAL- 1 3 0 0 /

NORMAL-210 'V

N O R M A L - 2 5 6 *\/

N O R M A L - 2 8 5 O/

F A L S E T T O - 2 5 6 'V,

FALSETTO- 3 2 0

F ig . 3

T Y P I C A L “O P E N "

F A L S E T T O - 4 8 0 0/

FRA MES - C O N D I T I O N S I

TO I E

S3

SUBJECT - A

Fa l s e t t o

normal

Fig. 4

BEFORE

AND

AFTER

T R A N S I T I O N - C O N D I T IO N I

24 Analyzing the sound*

Because of the marked pitch and

intensity changes that occurred during the filming of condi­ tion 5, this phase of the research was limited to the first four conditions for each subject* The audio-oscillator was first re-calibrated and was then used to test the frequency response of the sound analyzer.

This test was continued to the upper limit of

the latter*s range, i.e., 7500 cycles.

Next the response

characteristics of the magnetic tape recorder were checked over a frequency range of from 100 to 7500 cycles.

Pure

tones of constant intensity and at 100 cycle intervals were fed into the recorder from the oscillator.

As these were

played back the output from the recorder was connected to the analyzer on which intensity readings were made.

A curve

was constructed from these data (see Pig* 31 in Appendix B). The analysis of the sounds recorded during photogra­ phy was then undertaken.

Since all components of these com­

plex sounds could not be checked in the relatively short time the subject continued phonation, a section of the tape beginning immediately after the camera noise had subsided was cut out of the reel.

From this a loop was made just

large enough to fit snugly around the tape track of the re­ corder after the spools had been removed.

The playing of

this continuous piece of tape enabled the tone to be repro­ duced as long as was necessary fo.r the analysis.

A slight

alteration of frequency from t h a t of the original tone was noted, and was attributed to the difficulty in getting

25 exactly the right amount of tension on the loop.

However,

since it was assumed that this would result in only a slight, and at the same time uniform, frequency shift of all the partials, it did not appear to invalidate the process for the purposes of this study.

The output from the recorder

was then put through a voltmeter to insure constant inten­ sity and thence into the analyzer. After all four sounds for each subject were examined in this way* corrections for the response of the recorder were made and an acoustic spectrum for each sound was con­ structed (see Appendix B, Pigs. 27, 28, 29, 30). Limitations of the m e t h o d .

The rather considerable

advantages of the present approach over most other methods of laryngeal investigation have already been suggested here and detailed elsewhere (29).

There are, however, certain

limitations that at present seem inherent in the technique. In order to clarify the procedure these might well be intro­ duced at this point, and then, of course, must be kept in mind during the interpretation of results. One of the most serious restrictions is the limit it places on the number of subjects available.

Many willing

prospects find that they cannot tolerate the mirror in contact with the faucial arch.

Some may learn to increase their

tolerance sufficiently, but at the cost of considerable time, patience, and some discomfort.

Not all who can maintain the

mirror in position have the proper laryngo-pharyngeal confor­ mation to permit a view of the folds adequate for photography

26 of this kind.

Thus, even after considerable exploration,

it

was found necessary to limit the number of subjects for this study to two.

Obviously a larger sampling would have been

highly desirable, but it is felt that as more and more studies**- of this kind are completed the gradual accumulation of data obtained under the same or similar conditions will lead eventually to satisfactorily conclusive findings. Another limitation as far as the study of speech is concerned grows out of the necessity for maintaining a rela­ tively open oro-pharyngeal passageway.

This requirement

reduces drastically the number of speech sounds available for use in such experimentation,2 but will be seen to be a matter of minor significance in the present study.

Perhaps

more important is the possibility that the presence of the guttural mirror in the oro-pharynx m a y cause certain compen­ satory muscular adjustments which would distort the true laryngeal picture of normal, unimpeded voice production.

It

has been assumed, however, that such error, if it does exist, will be quite small, and will be relatively constant for all conditions of the current experiment. Still another difficulty was found in holding constant •kphe writer knows of seven similar studies, either completed or In progress, at two different universities, while he has reason to believe that a third is about to launch an extensive research program along the same lines. 2 The method would have limited application, for in­ stance, In testing Russell1s theory concerning the effect of laryngeal function on vowel quality (12, pp. 86 ff.), since probably no more than the three lowest front vowels could be observed.

27 the variables other than the experimental one--intensity in particular*

While this is a problem in all voice investiga­

tion (and of course in many other areas as well) the diffi­ culty was accentuated here, somewhat paradoxically, by the very shortness of the photographic period (less than two seconds) and the necessity for the extreme concentration of the subject in order to keep his laryngeal image pro­ perly located in the photographic field. however,

Theoretically,

it should be possible to surmount this difficulty,

and perhaps it should not be considered an intrinsic limi­ tation of the method which has been described.

PRESENTATION AND DISCUSSION OP RESULTS As already outlined, the purpose of this research was to study the action of the internal structures of the larynx during the production of voice in both normal and falsetto registers.

The major technique employed was high­

speed motion picture photography, by means of which it was possible to gain the effect of "slowing down" the very rapid motion of the laryngeal parts for more detailed ob­ servation of their activity.

Measurements of the movements

were made as the camera in effect successively stopped their progress in individual frames of the film at intervals of approximately 1/4000 of a second.

The results will be pre­

sented in terms of the various measureable aspects of the vibratory pattern and in terms of the action of the supra-

20 FRAM ES

OF

CYCLE

(N O

O P E N IN G IN F R A M E S

ONE

THROUGH T E N )

ru.

26 FRAM ES

OF

SCALE:

CYCLE

Fig.5 TRACINGS OF THE LARYNGEAL IMAGE FROM SUCCESSIVE FRAMES OF A TYPICAL CYCLE.

SUBJECT A -CONDITION I (LOW-PITCH IN NORMAL REGISTER)

5 TO I

C O N D IT IO N H

2

3

4

F R A M E S (N O O P E N IN S IN F IR S T TWO F R A M E S )

CONDITION H I

FRAM ES

(N O

O P E N IN G IN F IR S T S IX

FRAM ES)

Fig.6 TRACINGS OF LARYNGEAL IMAGES FOR TONES OF APPROXIMATELY THE SAME PITCH IN NORMAL AND FALSETTO REGISTERS.

SUBJECT A-CONDITIONS E AND IE

30

6

7

II

4

3

2

9

8

13

12

Fourteen

5

Frames

in

Complete

10

14 Cycle

Seale: 5 to I

FIG. 7. T R A C I N G S OF LA R YN G E A L IMAGES FOR CO ND ITIO N I E ( H i g h - f a l s e t t o ) — SU BJE CT A.

31

FRAMES

FR A M E S

F ig.8

TRACINGS

OF

THE

LA R Y N GE AL

IMAGE

FROM S U C C E S S IV E F R A M E S OF A T Y P I C A L C Y C L E .

S U BJ EC T B - C O N D IT IO N I

(L O W -P IT C H IN

N O R M A L R E G IS T E R )

F R A M E S - C O N D IT IO N I I

F R A M E S -C O N D IT IO N m

Fig.9

TRACINGS OF LARYNGEAL IMAGES FOR TONES OF APPROXIMATELY THE SAME PITCH IN NORMAL AND FALSETTO REGISTERS. SUBJECT B -CONDITIONS 1LANDH

OF

CM

LARYNGEAL

ro

CD

o.

°

1 o +o-

c

in

o o to

O)

CONDITION

_aj

FOR

CD

IMAGES

o 0

TRACINGS

EC (High - falsetto) - SUBJECT

10.

m

FIG.

33

CD

n the other hand, there was a marked

"crowding in” of these structures for the two falsetto con­ ditions in contrast to the more "open" configuration of the normal register. As a final comment on the results for Subject A, it may be said that the glide from normal to falsetto register tended to verify in broad outline the patterns summarized above.

In addition, a section of the film about 30 feet

from its beginning showed a sudden, short period of irregu­ lar vibratory action before settling down to the essentially typical falsetto pattern for this individual. A summary of the findings for Subject B follows. The differences in vibratory patterns between normal and fal­ setto registers were much less marked than those for Subject A, but some of the same tendencies did appear.

Generally

88 speaking, the extent of movement in the three main factors was reduced for the falsetto register (see Figs. 14, 15, IQ, 19, 22, 23).

A notable exception was in the length varia­

tion patterns where the low-falsetto condition actually showed a slight increase over the high-normal (see Fig. 2 6 J.1 Moreover, for all conditions there was little tendency toward further reduction in the high-falsetto.

In fact, the width

patterns showed an increase for this condition (see Figs. 18 and 19).

The Increase from low- to high-pitch In the

normal register was observed again in this subject, but she tended to show slightly greater activity in the high-falsetto than in the low. The varying length-to-width relation of the glottal opening showed the same general pattern for all conditions. However,the ratios were generally higher for the falsetto conditions, reaching a maximum for the whole experiment In the latter part of the cycle representing the low-falsetto (see Fig. 25). In the matter of the relative length of time In which the cycles of the four conditions remained "closed” (see above, p. 41, footnote 1) the low-pitch In the normal register showed a long closed phase--even longer than that observed for Subject A. high-normal,

It was again much shorter in the

and from there decreased regularly In the next

^It was suggested that the greater length of the Initial opening might account for this reversal of the other­ wise consistent tendency. i'

i j two conditions.

This latter reduction was so slight, how­

ever, that there is some question about its significance. (See Table II.) The conformations of the superior structures of the larynx for Subject B were such that more of the true folds was exposed to view for the combined falsetto conditions than for the two normal ones.

However,

there seemed to be

a slight tendency for the false folds to approach the midline during the falsetto, and the increased area between them may be accounted for in the tendency of the epiglottis to "ride into" the picture a little further on the two normal conditions (see Fig. 11). Finally,

in the glide from normal to falsetto regis­

ters the shift in pattern began to occur shortly after the beginning of the film, but there appeared to be no sharp break and no period of irregular vibration marked by the erratic sequence of cycles--that is, the transition was quite smooth compared with that of Subject A (Cf. 6, p. 51 and 23, p. 1631).

Gradually the glottal opening became

more and more restricted posteriorly.

About three-fourths

of the w a y through the film it was limited to the anterior half of the potential glottis and was considerably reduced in maximum width.

It should be added that there was at

least one closed frame in every cycle to the very end of the film* Conclusions.

A consideration of the questions posed

in the first section of this paper, and a careful analysis

of the results summarized above, lead the writer to offer the following tentative conclusions* 1*

The chief difference which distinguishes the

vibratory patterns of the vocal folds as the individual changes vocalization from normal to falsetto register is the tendency for the extent of fold movement to be reduced in the falsetto* a) That this difference is not the r©suit of the concomitant pitch change is indicated by the definite break in the "pitch trend” as the two registers are compared. b) The theory (8, p* 127) that in the falsetto the folds do not close completely at any time dur­ ing the vibratory cycle finds no support in this study. c) The tight pressing together of the posterior portions of the folds is not a necessary character­ istic of the falsetto--except, perhaps, at very high pitches within this register* 2.

The adjustments of the supra-glottal structures

of the larynx probably do not have a major role in distin­ guishing the two registers. a) The tendency sometimes observed for the ven-

I |

tricular folds to move inward for falsetto voice

j

(see Pigs. 3 and 4--Subject A) is not a necessary

| i | |l

pattern in producing the characteristic quality distinction between the registers.

This supports

the observation of Musehold (8, p. 126)* b)

Even in very high falsetto the ventricular

folds do not appear to impinge upon the true folds although some narrowing of the entrance to the ventricles may occur (Cf* 8, p* 130.)* 3.

^he differences between registers appear to be

far from consistent from person to person* a) While the reduction of the movements deter­ mining width and area of the glottis in the falsetto register occurs for both subjects, one subject shows this decrease to a much greater degree than the other. b) Many of the activity patterns studied, e.g., the relative lengths of the

closed and open phases

of the cycle, showed marked dissimilarities between individuals. 4.

The transition from one register to the other

need not involve a sudden marked change in laryngeal function* Impli cat ions.

It would be difficult to end a report

of this kind without a brief comment on the significance of the findings presented*

The

writer

is of the opinion that

research In this area is as yet not extensive enough to w a r ­ rant a complete or detailed description of the typical fal­ setto mechanism,

such as has been attempted (5, p. 73 f.)*

To the extent to which the techniques of this study permitted the accurate measurement of laryngeal activity, the results indicate that such activity may be less Important in

distinguishing th© registers than has been commonly reported (1, 4, 8, 11, etc.)*

The importance of a supra-laryngeal

factor is thereby suggested.

(Cf* 9, 22, 23, etc.)

On the other hand, the very wide variations in laryngeal function from individual to individual also re ­ ceives some emphasis*

(Cf. 1, p. 61.)

It is possible that

these individual differences are obscuring certain function­ al patterns which would serve to differentiate the registers. Finally,

the lack of similarity in the patterns shown

by the two subjects also suggests the possibility of a defi­ nite sex difference in laryngeal function.

The difference

in size of the vocal organs has been stressed frequently; it would be Interesting to investigate further the hypothe­ sis that there are distinct functional differences between male and female larynges. falsetto

Perhaps the distinction between

(male) and head (female) registers may prove to be

justified. It is clearly recognised that the limited number of subjects used In this study may lead to over-emphasis of individual or atypical differences in the laryngeal activity patterns which have been reported here.

For this reason It

is felt that further speculation on the significance of the above data can be most fruitful if postponed until these findings are supplemented by additional evidence from future researches of a similar kind.

APPENDIX A DATA PROM GLOTTAL MEASUREMENTS

94 T A B L E III

Glottal Width Measurements* Conditions I through IT: Subject A

Conditions

Frame XI

1

a 3 4 5

> a

§ 7 8 9

10 11

It 14 15 16 1#

U 19 20 21 22 23 24 25 26 27 28 29 30 31

.0 *0 .0

.0

.0 .0 .0 *0 *0 .0 .3 (a)** .6 (a) •9 (a) 1.2 (a) 1.5 (a) 2.0 (a) 2.2 (a) 2.2 (a-m) 2.1 (a) 2.3 la) 2.2 la) 2.0 (a-m) 2.1 (a) 1.8 (a-m) 1.8 (m) 1.4 (m) .8 (a-m) •8 (a-m) .5 (a) .3 (a) .2 (a)

.0 .0 .2 (a) .5 (a) •6 (a-m) 1.0 (a-m) 1.4 (a) 1.6 (a) 1.7 (m) 1.3 (a) 1.1 (a-m) .7 (m-p) •6 (a-m) •6 (m) .4 (a-m) •4 (a) .4 (a)

IV

III

.0 .0 .0 .0 .0 .0 .2 (a) •4 (a) .6 (a) 1.0 (a) .9 (a) .8 (a-m) .8 (m) •6 (a) •4 (a) .3 (a-m) .2 (a)

.0 .0 .0 .1 (a) •2 (a) .2 (a) .4 .4 .7 •6

.6 .2 .1 .1

(a) (a) (a) (a) (a) (a) (a) (a)

* In millimeters, rounded to the nearest tenth. **The symbols (a), (m)t and (p) represent the point at which these measurements were taken, i.e., the anterior, middle, or posterior third of the vocal fold length.

95 SABLB IV Glottal Length Measurement 3* Conditions I through IV: Subject A

Frame

Conditions

— I

II

III

IV

.0 .0 .0 .0 .0 .0

.0 .0 .0 .8 1.0

9.2

•4 •8

1.8 1.8

10.6 10.8 10.6 11.0

1.6 2.2 2.6

2.4

1 2

*0

.0 .0

3 4

.0 .0 .0 .0 •0 .0 •0 •0

2.4 4.0 5.8 7.0

' f -5 6

7

8 9 io ii if i& 14 15 18 17 18 19

20 21 22 25 24 25 28 27 28 29 50 31

•0

1.7 2.4 3*6 4*4 5.4 5.5 5.8 6.4 7.0

--------1

8.2

10.4 10.4 7.8 4.1

3.8 4.0 3.6 3.4 2.9

1.8

1.6

8.0 7.6 7.4 7.4 7.8 7.4 7.2 7.1 7.0 3.8 2.7 1.4

In millimeters» rounded to the nearest tenth.

1.4

2.6 2.6 2.6 2.2 .6

96 TABUS

V

Xength-to-Width Batios* Conditions I through IV: Subject A . .

Frame

1. 1—

. I I I .................. I II .

—

■ .»

in

.... I

,

,

in

■ ! • ■'

Conditions — 1 ■— *»■*.... — "' -■■■ .............. II III IV

X

2 12.0 8.0

3 4 5

9.6 7.0 5.8 5.7

6 7

8 & io ii i2 X3 14 13

16 *7 ip 19

20 21 22 23 24 25 26 27 28 29 30 31

6.2 8.1 5*6 4.0 4.0 3.6 3.6 2.7

9.6 15.7 17.3 17.3 19.5

2.6

4.5

10.2

8.0 2.0 2.0 2.7

2.2 2.8 4.7 5.0

6.0 8.5

10.0 8.0

2.9 3.3 3.5 3.4 3.7 3.5 4.3 4.1

6.1 8.8 8.7 7.6 9.0 7.0

* In millimeters, rounded to the nearest tenth*

5.0 7.0 4.5 4.1 3.4 4.0 4.3 13.0

20.0 6.0

97 TABUS VI Grlott&l Area Measurements* Conditions I through IV: Subject A

Frame

1

z 3 4

5

6 7

8 9 10 11 IE 13 14

is U

17 18 19 EO El EE E3 £4 £5

£6 £7

£8 £9 30 31

Conditions — .......... ■■■- ■ ■*........■— ..... I II III

♦0 .0 •0 •0 .0 .0 *0 .0 .0 .0

•4

•8

£•0 3 *6 5*6 7.6 9 .£

.0 .0 •4

1.6 £.4 5.£ 8.4

10.0 13.£ 1 E .0 9.£ 6.4 5.£ 4.4

£.0 l.£ •4

— ...... IV

.0 .0 .0 .0 .0 .0

.0 .0 .0 .1 .1

.£ .4 •8

•4

1.6 £.0 £.4 £.4

1.6

•£

.8 l.E •8

.8 •6

.£

.1

l.£

.6 •4

10.0 10 .£ IE.4

11.6 10.6

10.£ 9.6

8.8 6.8 4.8 3.6

1.6 .8 .£

square millimeters , rounded to the nearest tenth

98

1 I

TABLE VII Glottal Width Measurements* Conditions I through IV: Subject B

Conditions

Frame II

1 2 3 4 5 6 ’ sXJ i*f

8 9

10 11 1? 13 14 13 16 17 18 19

20 21 22

.2 Ip)** •2 (p) #2 (P> •2 (P) •2 (p) •2 (p) •2 (p) .2 (P) .2 (P) .3 (p) .3 (P) •4 •6 (a) •8 (a) 1#6 (a-m) 1.8 (a-m) 1#4 (a) 1.1 (a) 1.0 (a) #7 (a) .3 (a-p) •2 (p)

.3 #4 •4 #4

1.0 1.4

1.8 1.9

2.0 1.9 1.4

1.0 .9 *4 .3

(P) (p) (P) (P) (*) (*} (mj (m) (m) (a-m) (m) (a-m) (m) (m-p) (P)

III

.2 (p) .2 (P) •4 (p) •4 (m) .9 (m) 1.0 (m) 1.2 (m) . 1.0 (a-m) 1.0 (a-m) .6 (a-m-p) 5 (m) .3 (P) •3 (P)

IV .3 (P) .3 (P) .6 (m) 1.3 (a-m) 1.6 (a-m) 1.4 (a-m) .9 (a) .4 (a-m) .2 (m-p)

•

* In millimeters, rounded to the nearest tenth# **The symbols (a), (m) , and (p) represent the point at which these measurements were taken, i#e#, the anterior, middle, or posterior third of the vocal fold length#

99 f J?ABIM VIII Glottal Length. Measurements* Conditions I through IV: Subject B

Conditions I

1 2

7

1*2 1*0 1*1 1.1 1.0 1.0 1.2

8

1.3

9

3 4 5

6

tt

1.6 1.6 1 .*

12

3.0

13 14 15 IS 17 18 19

6.0 6.8

10

20 21 22

7.2 7.4 7.2 7.2

II

III

iv

2.6 2.6

4.8 5.4

2.0

5.0

8.2

6.6

6.2

9.8 9.6 9.8 9.8

7.2 7.4 7.6 7.4 7.2 5.0

9.0 9.0 9.8

10.0 10.0 10.0 9 .6 9.6 9.2 9.4 3.6

10.0 9.8

10.0 10.0 10.2 5.8

6.8 6.8 6*4

2.6

> In millimeters, rounded to the nearest tenth*

4.8

100 IABLE IX Length-to-Width Katios* Conditions I through IV: Subject B .■ia'f::;,,:'.'". 'ir.ajr.1-,i^:..:,yi,TTr;"“r.TT1..in’ :.'.,':.,ii....

Frame

—

...

i

--

Conditions »--- ----------- -------

ii

in 24.0 27,0 20.5 24.5

6.0

8.6

3 4 5

6

5.0 5.5 5.5 5.0 5.0

7

6.0

8

6.5

6.5 12.5 15.5 9>0 6.4 5.4 5.2 5.0 5.2

9

6.0

10 11 12

5.3 5.6 7.5

13 14 15 16 17 18 19

10.0

20 21 22

9.7 21.3 13.0

8.5 4.5 4.1 5.1 6.5

v

1^ "■- ; —

1

z

:"j.1/i;,VT3:'m1...i*si ,,a* ■■■?,".

10.6 9.8

8.1 10.0 9.8 16.6

6.8

20.0

9.6

34.0 19 .3

10.2 23.5

12.0

6.8

* In millimeters, rounded to the nearest tenth#

rv 6 .6 16.0

11.0 5.5 4.6 5.4

8.2 18.5 25.0

101 TABLE X Glottal Area Measurements* Conditions I through IV: Subject B

Frame

1 I

1 2 3 4 5

6 7

8 9

10 11 IS 13 14 15 16 17 18 19 SO SI 82

#3 «4 #4 #3 .3 •3 •4 •4 •4 •4 •4 •5

2.0 4.4 7.2 9.6 6.4

....

Conditions ...... — — II III *4

.8

.4 •4

.9

1.6

1.6

2.4 4.8

5.6 9.2 18.4 13.6 14.0 13.2

10.0 7.6 5.2 2.4 .8

6.8 8.0 7.2 6.4 4.8 3.2

.... ■— IV

.8 1.4

2.8 6.8 7.6 7.2 4.8

2.0 1.4

1.6 .8

6.0 4.8

2.8 l.S

.8

* In square millimeters, rounded to the nearest tenth#

APPENDIX B SOUND ANALYSIS DATA

103

o o

o o CM

CM

K)

ro

X

o o

O O (O

CL

register-Subject A.

Z

O CJ i=