Film Thech - Tecnología de cámara I

Fil m-Tech

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ALTHOUGH IT CAME INTO BEING ONLY A SHORT TIME AGO, THE MOTION

PICTURE |NDUSTRY; TODAY; IS ONE OF THE MAJOR INDUSTRIES OF THE WORLD-

TH|s INDUSTRY, HOWEVER, HA0 A HUMBLE BEGlNNlNG,JUST LIKE MANYOTHER

GREAT ENTERPRISES. EARLY PICTURES wen: BLURRY AND INDISTINCT a:cAus:

THE EQUIPMENT usso AT THAT 4__ Y

TIME wAs CRUDE,’ 0H-

PARATIVELY LITTLEWAS KNOWN

ABOUT THE ART or PHOTO-

GRAPHY- BuT,AsY:ARs PASSED

CONTINUED DEVELOPMENT TOOK

PLACE, NEH IDEAS van:

wonxco ouT, THE ASSOCIATED

EQUIPMENT vAs PERFECTED

AND, EVENTUALLY,RENARKABLE

RESULTS wens OBTAINED.

THE PICTURES, As we

KNOW THEM TODAY, ARE CLEAR

AND REALl5TIC- THEY ARE

SHOWN |n MAGNIFICENT THE-

ATERs, As HELL As IN THE

NEIGHBORHOOD "novnz", AND

ARE AVAILABLE To THE IN-

HABITANTS or THE SMALLEST

or TOWNS. HOWEVER, IN

SPITEOFALL TH\S ASTOUNDING

ADVANCEMENT IN THE ART or ; _

PHOTOGRAPHYAND MOTION FIC-

TURE PROJECTION SOMETHING F|G_ |

wAs STILL LACKING -- THE Rsconnaue A Sous Fon A Mus|cAL PICTURE

PAGE 2 souuo PICTURES

CHARACTERS DIDN'T SEEM ExAcTLY ALIVE As THEY WENT THROUGH THEIR Mo-

TIONS AND GESTURES IN AasoLuTE SILENCE. THE wHoLE THING, IN EAcT, WAS

JUST A MATTER or PAuT0M|HE, WHEN ALL OF A suoozn, RADIO PRINCIPLES wERE

INCORPORATED IN THE FILMING AND REPRODUCTION or PICTURES AND GAVE us

OUR MODERN SCUND PICTURES OF TooAY.

No LONGER no THE cHARAcTERs MovE ABOUT IN SILENCE 0R As sLAoows

BUT RAa|o HAs PUT LIFE INTO THEM, so THAT THE AUDIENCE ACTUALLY HEARS

THE VARIOUS CONVERSATIONS, soues ETc., JUST As THOUGH THE ACTORS wERE

ou THE STAGE. WITHOUT THE PRINCIPLES OF RA0|o, THE PRODUCTION OF TALK-

|~s PICTURES, As THEY ARE MAoE TqoAY, wouLn BE AN IMPOSSIBILITY AND

THEREroRE wE co NOT EXAGGERATE WHEN wE MAKE THE sTATEME~T THAT RAn|o

HAS REVOLUTIONIZED THE MOTION PICTURE INDUSTRY.

SINCE RADIO PRINCIPLES ARE so ALL-IMPORTANT TO souuo P|cTuREs, YOU

WILL REAo|LY REAL|zE THAT MosT EVERYTHING WHICH You HAVE so FAR LEARNED

T" I REGARDING RAn|o CAN BE APPLIED To

I sauna P1cTuaEs.|R EAcT,THE TRUTH or

THE MATTER IS THAT You HAvE ALREADY

LEARNED THE GREATER AND MoRE IMPOR-

TANT PART or THE TECHNICALITIES IN-

VOLVED IN souuo PICTURE WORK so THAT

IT rs How ONLY NECESSARY To RELATE

THEsE vAR|ous PRINCIPLES To THE"E|LM

ING" PROCESSES INVOLVED. THERE ARE

MANY ANGLES To THE PRODUCTION AND RE

PRODUCTION or souND PICTURES AND

so NATuRALLY,|T WILL REQUIRE sEvERAL

LESSONS IN WHICH TO D|scuss sucH A

LARGE SUBJECT. In EAcH or THEsE

souun PICTURE LEssoHs,wE HILL ons-

cuss CERTAIN PHASES or THE PRODUC-

TIDN AND REPRODUCTION or souuo AND

r|LM, so THAT upon COMPLETING ALL or

I THEM,You WILL HAvE A econ UNDERSTANB

“‘— sue or THE wHoLE SUBJECT INCLUDING

F1 G, 11 ozsc RECDRDlNG,F|LM RECOROlNG,STUDl?

.

:;h0o*579 8 :;C2,le_ TEcHH|QuE,THE OPERATION or "TALKIE

EQUIPMENT ETC.

In THE FIRST LESSON OF THIS sER|Es,wE WILL BEGIN WITH THE PRocEs§

Es INVOLVED |~ THE TYPE or sounn PlCTURES,lN WHICH THE souuo EFFECTS

ARE REcoRuEo on DISCS 0R As wE GENERALLY sAY,D|SC RECORDING.

THE STAGE "SET-UP"

A PORTION OF THE SOUND RECORDING PROCESS IS QUITE SIMILAR TO THAT

OF BROADCASTING- TO BEGIN WITH, THE SCENE IS CAREFULLY LAID OUT ON THE

STAGE, THE ACTORS ASSUME THEIR RESPECTIVE POSITIONS, THE LIGHTING EFF-

ECTS, CAMERAS ETC. ARE ADJUSTED SO THAT A PERFECT JOB OF PHOTOGRAPHY

CAN BE ACCOMPLISHED. IN ORDER TO HAVE A PERFECT REPRODUCTION OF SOUND

DURING THE FILMING, IT IS NECESSARY THAT THE SCENE BE ACOUSTICALLY TREA

TED, THE SAME AS IS DONE IN A BROADCASTING STUDl0,AND IN PICTURE WORK,

THIS IS GENERALLY DONE BY LINING THE BACKGROUND OF THE SCENE WITH NON-

RESONANT WOODEN sLAas, WHICH ARE KNOWN To THE INDUSTRY As "CELoTEx".

LESSON no.1

PAGE 9

LARGE WOOLEN QUILTS ARE ALSO FREQUENTLY USED FOR SOUND ABSORPTION PUR-

POSES, SO AS TO REDUCE ECHOES AND OTHER ANNOYING SOUNDS-

THE MICROPHONE IS PLACED AT THE MOST STRAGETIC POINT, WHERE IT IT

WILL FAITHFULLY PICK UP THE SOUND AS THE ACTORS MOVE ABOUT AND CARRY ON

THEIR CONVERSATION ETc.

AND VERY OFTEN, IT |s OF

couasz NECESSARY To use

SEVERAL MICROPHONES AT

THE SAME TIME. THIS IS

ESPECIALLY TRUE wnsn

"SHOOTING" A LARGE scsns

WHERE THE AREA To as cov

ERED as Too GREAT ro BE

ADQUATELY SERVED av ous

MICROPHONE.

|~ RESPECT TO MICRO

PHONE PLACEMENT,ONE MUST

ALSO consumes THE FACT

THAT IT |s NOT PERMISS-

IBLE TO HAVE THE MICRO-

PHONE snow m THE PlC- 8‘! Ow‘ Of Hm /ezcora/mg AF/Jara*us'

TURE AND FOR THIS REASON, THE MICROPHONE IS GENERALLY PLACED ABOVE THE

HEADS OF THE ACTORS, JUST HIGH ENOUGH TO BE EXCLUDED FROM THE RANGE OF

THE CAMERA LEN5E- IN FIG-2, YOU WILL SEE SUCH AN EXAMPLE OF A SUSPEND-

ED MICROPHONE, THE MICROPHONE IN THIS CASE BEING VISIBLE DIRECTLY ABOVE

THE ACTOR'S HEAD, WHILE THE CAMERA CAN BE SEEN IN THE FOREGROUND.

Foe THE PRESENT, we ARE JUST CONSIDERING THE STUDIO on STAGE "sET-

uP" IN A BRIEF WAY, SIMPLY |~ ounce To CARRY YOU THROUGH THE STEPS or

onsc RECORDING IN THE PROPER ssougucz BUT LATER, wE WILL DEAL WITH sTu-

DIO TECHNIQUE IN GREATER DETAIL.

- l _

‘I ARE OF

‘ ON THE

OFF TO

THE RECORD I NG

‘ APPARATUS

In F|c.§,You WILL

SEE A GENERAL LAY—OUT

I or THE RECORDING APPAR-

_ ATUS AND THE CAMERA.THE

MICROPHONE AND CAMERA

nouns: LOCATED

SET (scEuE)wn:LE

‘ THE MONITOR, AMPLIFIER

AND RECORDER ARE LOCAT-

ED IN SOUND PROOF ROOMS

ONE SIDE OF THE

STAGE on sET nnown AS

"MONITOR ROOMS"AND GEN-

, _ __ ERALLY THEY ARE EQUIP?-

ED WITH A THICK GLASS

F

_ _ Ia" 4 wmuow, so THAT Tl-IE OP-

7700 Ezcora///1 Uh/f5 Or/Ven S I16/Irarlau /

9 _ V 5‘! E"ATORS cm ossznvs THE

W1 fh Camera s,

PAGE U souuo PICTURES

ACTIONS GOING ON AS THEY OPERATE THEIR CONTROLS. THIS WOULD BE EQUIVA'

LENT T0 THE CONTROL ROOM OF A BROADCAST STATION WHILE THE SET CORRES-

FONDS TO THE BROADCAST STUDIO.

FOR SOUND RECORDING, THE MICROPHONE MUST BE OF A VERY HIGH QUALITY

TYPE,AND THE MONITOR CONTROLS THEMICROPHONE OUTPUT RAISING OR LOWERING

IT AS THE OPERATOR FINDS IT NECESSARY -- AT ALL TIMES BLENOING IT T0

GIVE THE BEST EFFECTS POSSIBLE. THIS MONITOR IS ESSENTIALLY THE SAME AS

THE MIXER USED FDR BROADCAST PURPOSES, AND WHICH WAS INTRODUCED TO YOU

IN THE SERIES OF LESSONS TREATING WITH BROADCAST STATIONS-

FOLLOWING THE MONITOR,WEHAVE A HIGH GRADE AUDIO rnzouzucv AMPLI-

FIER ar CONVENTIONAL ossxsn BUT INSTEAD OF runs AMPLIFIER'S ourpur OP-

ERATING A SPEAKER, AS 1~ PUBLIC ADDRESS WORK, on FEEDING INTO A TRANS-

MITTER CIRCUIT AS IN A BROADCAST svsrzn, THE AMPLIFIER or THE souuo

RECORDING SYSTEM |s usco TO OPERATE A RECORDER.

WHEN USING MORE THAN ONE MICROPHONE, AS IS OFTEN THE CASE,THEN THE

VARIOUS MICROPHONES CAN ALL BE FED INTO A MIXER, THE SAME AS IN RADIO

OF THEM CAN BE CUT

OUT OF OPERATION AS

AND IF IT IS NECESS

HAVE THE MICROPHON-

 “

I  __.

a§§§

ES LOCATED AT A CONSIDER-

ABLE DISTANCE FROM THE HIE

ER ANO AMPLIFIERJTHEN AN

INTERMEDIATE OR LINE AMP-

LIFIER CAN BE INSTALLED IN

THE CIRCUIT BETWEEN THE

MONITOR AND MICROPHONE DUI

PUT SO AS TO PREVENT TOO

GREAT A LOSS OF MICROPHONE

ENERGY»

PRACTICE, so THAT ANY ONE

OR ALL

SEE TWO RECORDING MACHINES MOUNTED SIDE BY SIDE. FUNDAMENTALLY, THEY

ARE NOTHING MORE THAN A PAIR OF HIGH GRADE LATHE5, EACH PROVIDED WITH A

TURNTABLE WHICH CORRESPONDS TO THE TURN TABLE DN A PHONOGRAPH. THESE

RECORDING MACHINES ARE ARRANGED TO BE DRIVEN SYNCHRONOUSLY WITH THE

CAMERA-THAT lS,THE SPEED OF THE TURN TABLE AND THE LATERAL.MOTIDN OFTHE

RECORDING UNlT(RECORDER CUTTER)MUST BE PROPERLY TIMED WITH THE SPEED AT

WHICH THE RIBBON TYPE FILM IS BEING UNREELED THRU THE CAMERA. THIS MUST

BE DONE IN ORDER TO KEEP THE SOUND AND FILM IN STEP WITH EACHOTHER, A5

OTHERWISE THE ACTORIS MOTIONS

HE IS SPEAKING ANO THIS WOULD

ALTHOUGH ONLY one CAMERA

PRACTICE TO "snoor" THE scans

Iv ru|s case, THE CAMERAS cnu

LLEL, ALL or rnzu BEING svncunownzzu TO THE spszo OF THE asconouue

CHINE.

WOULDN'T CORRESPOND WITH THE WORDS THAT

NATURALLY SPOIL THE RECORDING-

|s suowu nu F|s.}, YET IT IS A common

wurn SEVERAL CAMERAS AT THE SAME TIME.

as cousnosazo AS aenus OPERATED IN PARA-

MA-

LESSON No.1 PAGE 5

THE RECORDING UNIT

Now IN F|c.5, WE HAvE A SIMPLE DIAGRAM, ILLUSTRATING THE FUNDAMEN-

TAL PRINCIPLE w|TH wH|cH A RECORDING UNIT cAH BE MADE TO oPERATE.NoT|cE

THAT wE HAvE A PIECE OF sort IRON BENT INTO THE sHAPE or A HoRsEsHoE. A

PAIR OE_"UY SHAPED PGkE'PTECES“iRE THEN MOUNTED TO THIS LARGE MAsHET,so

THAT WE HAvE A PAIR or NORTH POLES on one SIDE AND A PAIR or souTH POL-

Es on THE oTHER. TH|s MAGNET |s ENERGIZED av A FIELD COIL THROUGH wH|cH

A D.C. SUPPLY IS FLOWlNG-

AT THE cEHTER, wE HAvE A LIGHT METAL (|RoH) ARHATuRE, WHICH us

FLEXIBLY PIVOTED AT ITS cE~TER AND A SHARP CUTTING TooL MADE OF FINELY

GROUND sAPH|RE, PROPERLY CALLED A STYLUS, IS MOUNTED ON THE LowER END

OF THIS ARMATURE. THE ARHATuRE IS NORMALLY BALANCED nu: TO THE EFFECT

or THE NORTH AND SOUTH POLES UPON IT, coHsEQuEHTLY, |Ts NORMAL POSITION

LIES IN A vERT|cAL PLANE As |LLusTRATE0 IN F|s.5.

A "vo|cE co|L", MADE UP IN

Two sEcT|oHs,suRRouH0s THE ARM- if? tf:_

ATuRE IN THIS PARTICULAR EXAMP- p1** (“ “

LE AND THE ENDS OF THIS "vo|cE  \

co|L" ARE CONNECTED To THE OUT- /*q§\ ‘ §§§?§?==$$

PUT TERMINALS of THE AUDIO AHP— 4;fZi_;ii§%:g;§;3¥

LIFIER. THEREFORE,AS THE VARY- _ :1 gwq ‘A HML T

znc CURRENTS or souuo FREQUENCY F-b§§"I“*\i§;7“‘§:""

FLOW THROUGH TH|s co|L,THE MAG— _ ' ”>“ f“-"l,:E“‘E*.;-‘l?’

NETIC REACTION WILL BE sucH As A \_,_,\“S "" I i

To cAusE THE ARMATURE To osc|LL 

ATE on ROCK To AND FRO on ITS

PIVOT AND |~ STEP WITH THE A.F. »

CURRENT VARIAT|ONS- In GENERAL PKG 6

RESPECTS TH|s UNIT us QUITE SIM - '

ILAR To A BALANCED ARHATuRE TY: C”#'”-7 hag Wax‘

PE SPEAKER uH|T,oHLY THAT INSTEAD or TRANSFERRING THE ARMATURE MOTION

To A SPEAKER DIAPHRAGM, TH|s MOTION |s USED To MOVE THE sTTLus FROM

SIDE To SIDE IN DIRECT RELATION To THE AUDIO FREQUENCY vAR|AT|oHs THRu

THE "vo|cE co|L".

R"

So FAR, YOU cAH sEE How IT ls POSSIBLE To MAKE A CUTTING TOOL va-

BRATE IN A DIRECT RELATION To THE AUDIO FREQUENCIES, HH|cH ARE IMPRESS-

ED upon THE DIAPHRAGM or A MICROPHONE, REeARoLEss or HHETHER THE souno

BE Hus|c, sPEEcH, OR JUST NOISE. THE THING TO no How IS To TRANSFER

TH|s MOTION OF THE STYLUS OR CUTTING TooL TO SOME SUITABLE MATERIAL, so

THAT IT WILL cuT IMPRESSIONS IN IT, CORRESPONDING ExAcTLY To THE VIBRA-

TIONS WHICH THE ARHATuRE or THE RECORDING TooL uHoEReoEs. WE THEN HAVE

A RECORD or THE STYLUS v|aRAT|ous, As HELL As OF THE AUDIO FREQUENCIES

CAUSING THEsE sAME VIBRATIONS. LET us How PROCEED AND sEE How THIS IS

cons IN PRACTICE. I

CUTTING THE WAX

TO BEGIN WITH, IT IS OBVIOUS THAT THE SUBSTANCE,lNTO WHICH THESE

SOUND IMPRESSIONS ARE TO BE CUT, MUST BE SOFT ENOUGH SO A5 T0 PERMIT

PAGE 6

SOUND PICTURES

THE ARMATURE AND CUTTING TOOL OF THE RECORDING UNIT TO HAVE FULL FREE-

DOM OF MOTION. THE SUBSTANCE USED FOR THIS PURPOSE CONSISTS OF STEARIN,

MONTAN WAX AND EITHER LEAD OR ALUMINUM. QREAT CARE MUST BE EXERCISED

THAT IT WILL BE OF THE CORRECT DENSITY AND FREE FROM GRIT AND AIR HOLES

THIS IS GENERALLY REFERRED TO AS A "WAX" AND IT IS SHAPED INTO DISCS,

WHICH ARE FROM ONE TO TWO INCHES THICK AND FROM THIRTEEN T0 SEVENTEEN

INCHES IN DIAMETER.

BEFORE RECORDING ON THIS DISC OR WAX, IT MUST FIRST DE PLACED IN

A LATHE AND SHAVED TO A HIGHLY POLISHED SURFACE. THE WAX IS THEN PLACED

ON THE TURN TABLE OF THE RECORDING MACHINE AS SHOWN IN FIG.6 AND AS THE

RECORD IS ROTATED BY THE TURN TABLE, THE RECORDING UNIT IS GRADUALLY

CAUSED TO TRAVEL IN A STRAIGHT LINE ALONG A HORIZONTAL PLANE AS INDICA-

Tao av rue ARROW IN F|a.5.

THUS IF THE STYLUS OR CUTTING TOOL BEARS DOWN UPON THE WAX WITH SB

FFICIENT PRESSURE, IT CAN BE SEEN THAT A SPIRAL GROOVE I5 CUT INTO THE

WAX SURFACE STARTING AI THE CENTER AND FINALLY ENDING UP AT ITS RIM. IN

 -*

I11§'\111I\\i\\\\

——sn-———

FlG1.7

MODERN RECORDING PRACTICE,THI5 GROOVE IS

KEPT AT A CONSTANT DEPTH AND WITHOUT ANY

MODULATING CURRENT FLOWING ranoucu THE

COIL 0F THE RECGRDER,§T CAN BE SEEN THAT

THlS_PROC€SS WILL PROVIDE A UNIFORM SPIRAL

GROOVE wuscu ONLY FORMS A "TRACK", so TO

SPEAK,BUT moss Nor RECORD ANY SOUND.

NOW IF WE SHOULD REPEAT THE PROCESS

AS JUST DESCRIBED BUT IN ADDITION,PA5S AUQ

IO FREQUENCY CURRENTS THROUGH THE COIL OF

THE RECORDING UNIT,THEN THE STYLUS WILL Vi

BRATE FROM SIDE TO SIOE,AT THE SAME TIME

- THAT IT CUTS THE SPIRAL GROOVE THEREFORE

MocIuI'aI':zcI Qzcordlnq Gram/e5. ' ’

INSTEAD OF HAVING A UNIFORM SPIRAL GROOVE

cur INTO THE WAX, THESE GRQOVES WILL HAVE IRREGULARITIES CUT IN EACH or

THEIR SIDES SOMEWHAT AS ILLUSTRATED BY THE HIGHLY MAGNIFIED REPRESENTA-

TIONS IN Fles. T AND 8.

THE WAVY PORTIONS IN THE GROOVE ARE THE AUDIO FREQUENCY MODULA-

TIONS, WHICH ARE RECORDED ON THE WAX AND THEY ARE AN EXACT REPRODUCTION

OF THE AUDIO FREQUENCIES,WHICH ARE IMPRESSED UPON THE MICROPHONE OFTHIS

RECORDING SYSTEM. IN OTHER WORDS, INSTEAD OF USING THE AUDIO FREQUEN-

CIES IN A SPEAKER UNIT TO PRODUCE IMPRESSIONS ON THE SURROUNDING AIR

AND THEREBY DELIVER SOUND TO OUR EARS, WE SIMPLY USE THIS ENERGY TO CUT

CORRESPONDING IMPRESSIONS INTO A WAX DISC. LOW FREQUENCIES WILL PRO-

DUCE A LONG WAVY IMPRESSION, WHEREAS THE HIGHER FREQUENCIES HAVE THEIR

IRREGULAR IMPRESSIONS CROWDED CLOSELY TOGETHER. THE COMMERCIAL TYPE

PHONOGRAPHS HAVE THEIR RECORDS CUT S0 THAT THE RECORDING IS STARTED AT

THE RIM OF THE RECORD AND IS ENDED AT THE CENTER. THE RECORDINGS FOR

TALKING PICTURES AND EVEN FOR RECORDED BROADCAST PROGRAMS ARE JUST THE

OPPOSITE IN THIS RESPECT BECAUSE IN THESE CASES,THE RECORDING IS START-

ED AT THE CENTER OF THE DISC AND CONCLUDED AT THE RIM.

A DETAILED DRAWING OF THE STYLUS POINT, AS uszo IN THE "VITAPHONE

THE CORR-

ESPONDING AMPLITUDE AT §,OGO CYCLES ls ONLY .0001", PROVIDED THAT THE

souuo I5 CONSTANT IN AasnLuTE INTENSITY OVER THE INTERVENING RANGE-

THE wAx ens: MUST as LEVELED IN THE R5

consume MACHINE WITH REASONABLE CARE AND

THE STYLUS MUST BE SHARP AND or A SHAPE To

INSURE A CLEAN cur. To AID IN MAINTAINING

THE cur AT THE c0RR£cT DEPTH, A so ¢ALLEn

"AnvA~cE BALL" RIDES LIGHTLY ovaq THE sua-

FACE or THE DISC,SUPPORTING THE STYLUS AT

THE PROPER HEIGHT IN spur: or QMALL INACCUR

ACIES IN LEVELLING THE DISC OR DEVIATIONE

Illllllllili III

FROM FLANENESS. FOR ADJUSTING THE ADVANCE

BALL WITH RESPECT TO THE STYLUS,THE GROOVE

$ERVEQ WITH A CALIERATED MICROSCOPE

THE Cb? I5 MADE IN THE DISC,THE WAX

IN THE RECORDS usEo WITH THE WESTERN ELEcTR1c APPAnAT¢§,THE LINEAR

SPEED or THE GROOVE PAST THE REPRODUCER POINT RANGE5 FROM I40 FT. PER

NUTE AT THE OUTSIDE or THE EPTHAL To 70 FT. PER MINUTE AT THE |~5IFE-

THE =ATE or ROTATION |s OF COURSE DEFENDENT upon THE ouTEH QIAHETER OF

THE cnoovss, WHICH IS DETERMINED PRIMARILY av THE LENGTH 0F TIME T0 BE

VERED BY A SINGLE DISC.

Do NOT FORGET, HOWEVER, THAT THE CAMERA AND THE TURNTABLE or THE

RECORDING MACHINE MUST BEAR A DEFINITE RELATION To EAcHOTHEP A8 REGARBS

THEIR OPERATING SPEED AND THAT A common DRIVING MOTOR IS FREQUENTLY EM-

PLOYED FOR THEsE Two UNITS AND IN THIS CASE THE cAMERAs A97 CQNTAINED

WITHIN souuo Pnoor BOOTHS THE SAME As THE RECORDING MAcHINE5- BY MEANS

or GEARS, SUCH A HAcHaHE RUNNING AT A CONSTANT sazzo or USUALLY I200

R.P.M. MAY as MADE To TAKE THE RIBBON-LIKE FILM THROUGH THE CAMERA AT A

STANDARD SPEED or 90 FT. PER MINUTE, WHILE THE TUFN TABLE OF THE RECOE2

|~c MACHINE REVOLVES AT }j R.P.M. BY CONTINUALLY MAINTAINING THEEE

SPEED RELATIONS, THE souno EFFECTS uPo~ THE RECORD WILL BE SYNCHRONIZED

’ P“

Emu‘

I‘ ‘ V

ggfi

1:1:-..9

[>z£aZ$ af 5&2 Clzfi

WITH THE FILM.

lr IT IS DESIRED To SEPARATE THE

souwu AND PICTURE REcoHoERs, THENT THuavin-

uAL MOTORS ARE useo, wH|cH ARE USUALLY OF

THE SYNCHRONOUS ALTERNATING CURRENT TYPE-

Bv HEAHs OF usI~s"FAoERs" WITH THE AMPLIFI-

ER, THE RECORDING CAN BE CQNTINUEU on AH-

OTHER wAx vHE~ ONE or THE RECORDS as CUT

AND IF CAREFULLY JONE,THlS CHANGEQVER WILL

PRODUCE no NOTICEABLE EFFECT-

PAGE 8

SOUND PICTURES

USE OF THE PLAYBACK ON THE WAX DISC

AFTER A RECORD HAS BEEN CUT, THE SOUND HAY BE REPRODUCED DIRECTLY

FROM THE VAX BY MEANS OF A SUITABLE PICKUP OR REPRODUCER BUT THE ORDIN-

FlG.IO

M/Icroscap/I: Exam/'r1a/‘Far! cf 1‘/le Pecard.

ARY TYPE OF REPRODUCER5 REST

I T00 HEAVILY an THE RECORDS. As

‘ A MATTER or FACT,THE VERTICAL

PRESSURE BETWEEN THE NEEDLE

POINT AND THE RECORD IN AN oa-

DINARY PHONOGRAPH ls APPROXI-

MATELY 50,000 LBS. PER SQUARE

INCH. THEsE HIGH PRESSURE HAvE

BEEN NECESSARY IN THE PAST IN

ORDER THAT THE RADIAL‘ MOTION

or THE NEEDLE wouuo BE or THE

PROPER HAGNITUOE As IT PAssEs

THROUGH THE MODULATED GROOVE

or A FINISHED REcoRo.0avIousLT,

SUCH PRESSURES wounn DESTROY A

GROOVE IN wAx AND ANY REDUC-

TION IN THIs NEEDLE PRESSURE

MUST THEREFORE BE ACCOMPANIED

av A Rsoucrseu IN THE MASS AND

STIFFNESS OF THE REPRODUCER.

So IN ORDER To MEET

THEsE CONDlTl0NS,SPEClAL"PLAY—

EAcKs", As THE REPRODUCER5 ARE

CALLED, HAVE BEEN DEVELOPED so THAT THE souuo CAN aE REPRODUCED FROM

THE ORIGINAL WAX RECORD wITH PRACTICALLY THE SAME QUALITY AS OBTAINED

wusu usnus THE BEST TYPE OF ELECTRIC PICK UP wITH THE FINISHED RECORD.

SucH A SPECIAL "PLAYaAcK" IS suowu IN FIc.I1 AND THROUGH ITs usE, THE

QUALITY or THE RECORDING CAN BE JUDGED AND PASSED UPON BEFORE GOING

THROUGH THE FOLLOWING PROCEDURES wITH ITS ACCOMPANYING EXPENSE. In OTH-

ER woaos, IF THE RECORDING DOES NOT COME uP To STANDARD, IT CAN as DONE

OVER AGAIN BEFORE EVER PASSING IT THROUGH THE FINISHING PROCESSES.

MAKING THE MASTER RECORD

AFTER THE WAX RECORDING IS PRONOUNCED A5 BEING 0.K. IT IS TAKEN TO

THE "GALVANO BATHS" AND DURING THIS TRANSPORTATION GREAT CARE MUST BE

EXERCISED SO THAT THE DELICATE GROOVES ON THE WAX ARE NOT MARRED. THE

USUAL PROCEDURE AT THIS TIME IS TO BRUSH A SPECIAL FINE POWER OVER THE

GROOVED-SIDE OF THE WAX. THIS POWDER HAS THE IMPORTANT PROPERTY OF BE-

ING A sooo CONDUCTOR FOR

AN ELECTRIC CURRENT AND

BECAUSE or TH|s, IT Is

KNOWN TO THE INDUSTRY As

"CONDUCTING PownEn".’

THE TREATED WAX IS

NOW ATTACHED TO THE END

OF A LONG ARM,WHICH SWI-

%I

T W ET 211221 |

F I 6 . II. I

A "/7/agback " fir Pa/are ¢/uc//'0/-I ff-my Il/ax D/31-5_

LESSON no.1 PAGE 9

sHEs IT BACK AND FORTH THROUGH THE "BATH" on ELECTROPLATING SOLUTION

AND GRADUALLY A COPPER COATING WILL FORM on THE cur SIDE or THIS 0|sc,

wH|cH FINALLY TURNS INTO A COPPER PLATE. TH|s COPPER PLATE IS CALLED

THE "MAsTEH" AND WHEN IT IS PEELED FROM THE WAX n|sc,|T IS A"NEsAT|vE".

THAT |s, THE ORIGINAL RECORDING enoovcs ARE How DUPLICATED on THE copp-

ER PLATE |~ THE FORM or LINES, WHICH ARE RAISED ABOVE THE suHFAcE. In

F|e.12 vou ARE snown THE ELECTROPLATING TANKS AT one OF THE MAJOR STU-

o|os.

THE TEST PRESSINGS

THE COPPER MASTER IS THEN PLACED IN A HUGE PRESS, PREPARATORY TO

MAKING A PAIR OF TEST PRESSINGS. THESE PRESSINGS ARE MADE OF A COMBIN-

ATION EARTH AND SHELLAC MATERIAL, WHICH IS HEATED TO THE CONSISTENCY OF

DOUGH AND PLACED WITH THE MASTER. THEN UNDER ENORMOUS HEAT AND PRESSURE

THE RECORDING LINES OF THE MASTER ARE IMPRINTED INTO THE TEST PRESSINGS

SO THAT THE TEST PRESSINGS ARE DUPLICATES OF THE WAX RECORDING.

THE TEST PRESSINGS ARE THEN PLAYED WITH A PHONOGRAPH PICK UP AND

IF UP TO STANDARD, THE FOLLOWING PROCESSES ARE NOW IN ORDER. IT SEEMS

LOGICAL THAT THE FINAL PRESSINGS CAN NOW BE MADE FROM THE MASTER HUT

THIS IS NOT DONE IN PRACTICE- THE REASON FOR THIS IS THAT IF IN THE

PRESSING PROCESS, THE MASTER SHOULD FOR SOME REASON OR OTHER BE MARRED,

NO IMPRESSION OF THE ORIGINAL RECORDING WOULD REMAIN FROM WHICH MORE

PRESSINGS COULD BE MADE- YOU WILL REMEMBER THAT THE WAX HAS ALREADY

BEEN

TIME

BEEN

MORE

SPOILED WHEN THE MASTER WAS TAKEN FROM IT AND THE WAX HAS BY THIS

PROBABLY ALREADY

SHAVED AND IS ONCE

READY FOR USE IN RE

CORDING ADDITIONAL PARTS

OF THE PICTURE.

THE MOTHER AND

STAMPER

Foa THE ABOVE MEN-

TIONED REASONS,THE MAs-

TER IS NOW ELECTROPLATED

AND THE RESULTING COPPER

o:sc us CALLED THE"MoTH-

ER". THE "MoTHER"THus B5

coMEs AN EXACT DUPLICATE or THE ORIGINAL WAX AND WITH THIS nous, THE

MASTER as CAREFULLY FILED AWAY FOR EMERGENCY on FOR FITTING FUTURE on-

osns or THE sAME PORTION OF THE PICTUPE RECORDING. THE "MoTHER" IS THEN

IN TURN ELECTROPLATED AND THE NEGATIVE COPPER nusc, wH|cH THIS PROCESS

PRODUCES, as CALLED THE "STAMPER".

Fin

T/7 Z E/ec 1‘/‘op/a 2‘/-ng /Qaarfl.

THE "sTAMPER" |s THEN CAREFULLY enouuo AND suFFEb AND OTHERWISE

PREPARED. IT IS THEN PLACED nu THE PRESS, TOGETHER WITH THE EARTH-sHEL£

Ac MATERIAL AND THUS THE FINAL DISCS ARE PRESSED OUT To THE DESIRED Mqg

BER- tr MANY PRESSINGS ARE NEEDED, THEN SEVERAL STAMPERS ARE MADE az-

cAusE THE usE or one STAMPER FOR Too MANY PRESSINGS LESSENS THE CLARITY

AND SHARPNESS or THE DISCS AFTER A T|ME. HowEvER, IT |s NOT UNUSUAL TO

MAKE A THOUSAND PRESSINGS FROM A SINGLE STAMPER.

gm: 10

SOUND PICTURES

THE FINISHED RECORDS LOOK JUST LIKE THE ORDINARY DISC TYPE PHONO~

GRAPH RECORDS ONLY THAT THEY ARE LARGER IN DIAMETER AND THE RECORDING

STARTS AT THE CENTER AND IS ENDED NEAR THE RIM OF THE RECORD- THE POINT

AT WHICH THE RECORDING STARTS IS MARKED, GENERALLY WITH A WHITE LINE

THAT THIS POINT CAN BE DETERMINED READILY DURING PRODUCTION-

»»‘=?‘)

F1 G . I5

72¢ Wésvlern E/zc/rfc

Qelpra duce/1

THE RECORDED SOUNDS CAN BE REPRODUCED-

ALTHOUGH IT IS ACTUALLY POSSIBLE TO USE

EXPLAINED.

OIL-DAMPED PICK-UP

THE ELECTROMAGNETIC PICK-UPS WHICH ARE USED FOR SOUND PICTURE WORK

AS WELL AS FOR THE REPRODUCTION OF ELECTRICAL TRANSCRIPTION RADIO BROAD-

CASTS AND OTHER USES WERE HIGH QUALITY REPRODUCTION IS REOUIRED,ARE GEN-

ERALLY OF THE OIL—DAMPED DESIGN. A PICK—UP

I

HEAD or-' THIS TYPE IS SHOWN IN F|s.1§ AND ITS °m_EflcASE#g"7E*\ ~fif%'%"

INTERNAL CONSTRUCTION IS ILLUSTRATED IN FIG.  I

11"‘ cu-rcn if K,

¢<>i'£‘2ET.~¢. 335- '

BY STUDYING F|s.11I CLOSELY You WILL N_g """" Q55}:

TICE THAT THE NEEDLE IS ATTACHED TO A METAL T5;=5|AulNJRsgru_3‘ Q"-3_i

DIAPHRAGM MADE or TORSION—STEEL mo WHICH us pW|____\_

MAGNETICALLY CONNECTED To ONE POLE OF THE ‘ I

FIELD MAGNET- THE OTHER POLE OF THE MAGNET

TERMINATES IN A SHOE wmcn CONSISTS or Two *s°,¢§§fi" *1“:-

aamcuss on FORKS mo UPON wmcn ARE MOUNTED s‘§‘7§‘E,"".___, / |

THE PICK-UP COILS- THIS FORM OF CONSTRUCTION ncrimgmaé M»:?NIgusgK:

SHORTENS MATERIALLY THE LENGTH OF THE PATH

FOR THE FLUX THROUGH NON—MAGNETlC MATERIAL

AND THEREBY INCREASES THE FLUX DENSITY A5

WELL AS THE MAGNETIC LIFE.

IT IS OF COURSE UNDERSTOOD THAT MANY

RECORDS GO TOGETHER,lN ORDER TO MAKE UP THE

COMPLETE SOUND RECORDING OE THE PICTURE

THESE FOLLOW EACHOTHER IN CONSECUTIVE ORDER

WITH ONE BEGINNING WHERE THE OTHER LEFT OFF

PICK—UP UNITS

IN A PREVIOUS LESSON TREATING WITH.RA

DIO-PHONOGRAPH COMBINATIONS,YOU LEARNED A-

BOUT THE ELECTROMAGNETIC TYPE PHONOGRAPH

PICK-UP UNIT AND THEREFORE IT WILL NOT BE

NECESSARY TO REPEAT ANY INSTRUCTION REGARD-

ING IT AT THE PRESENT TIME. BY PLACING

SOUND PICTURE RECORD ON A TURNTABLE,PERMITl

ING THE PICK—UP UNIT TO RIDE THE GROOVE AND

CONNECTING THE PICK-UP ACROSS THE INPUT TERMINALS OF AN A-F. AMPLIFIER,

AN ELECTROMAGNETIC PICK-UP

UNIT IN THE MANNER JUST DESCRIBED, YET IN ACTUAL PRACTICE,PICK—UP DEVI-

CES OF HIGHER QUALITY ARE USED FOR SOUND PICTURE WORK- THIS SHALL NOW BE

FIG. I4

Ggns/-ruc;L/Bn of 0//—Jarr1/::a/

P/'ck— -'1/O.

,so

LESSON no.1

PAGE II

WHEN THE NEEDLE IS CENTERED OR IN ITS NEUTRALPOSIT|ON,THENTHE FLUX

DENSITY BETWEEN THE DIAPHRAGM AND BOTH OF THE COIL SUPPORTS IS EQUAL.

THEN AS THE NEEDLE MOVES FROM SIDE TO SIDE THE DIAPHRAGM IS DISTORTED

IN AN s—SHAPE SO AS TO BE NEARER ONE OF THE COIL SUPPORTS AND FARTHER

FROM THE OTHER. THIS CAUSES A RE—DISTRIBUTION OF THE FLUX,RE5UCTING IN

AN INCREASE IN LINES OF FORCE PAST

THE COIL WHICH IS MOUNTED ON THE

SUPPORT NEAREST THE DIAPHRAGM AND

A REDUCTION IN THE LINES OF FORCE

PAST THE OTHER COIL.

THIS CHANGE IN FLUX DENISTY AT

BOTH coILs CAUSES AN E.M.F. TO BE

INDUCED IN EACH or THEM AND SINCE

THE Two coILs ARE CONNECTED IN sag

IES THE Two E.M.F s ARE ADDED To-

GETHER. THEN WHEN THE NEEDLE IS 05

FLECTED IN THE OPPOSITE DIRECTION

av THE GROOVE IN THE RECORD, THE

DIAPHRAGM Is ALSO DISTORTED IN THE

OPPOSITE DIRECTION CAUSING THE IN-

DUCED E M.F‘s IN THE COILS ALSO To

Aw//C Crysinl e Zr/2”

\

e

I

Adk\‘/ Ram”

Pickup Head, ’ ’ ' C 0:01 fierba/ahced

_\ _ Torre Arm

 ::_ , N

Bhwn Bnhhk

Ophlflhmwf Mwflhgflne

/'7

\

BE REVERSED THUS WE HAVE A COM-

PLETE A.C- CYCLE FOR EACH COMPLETE

SWING OF THE NEEDLE.

FIG.I5

T/72 Cry51Ia/ 71,/_:¢ /7/2/Q-go F/ead,

$0 AS TO PROVIDE A STILL GREATER DAMPING EFFECT THAN THAT FURNISH

ED BY THE STRESS OF THE DIAPHRAGM ALONE, THE ENTIRE ASSEMBLY IS ENCLOS-

ED IN A CASE WHICH IS FILLED WITH OIL» THIS OIL WILL EXERT A PRESSURE A

GAINST THE DIAPHRAGM AND THEREBY INCREASE THE DAMPING EFFECT-

THIS TYPE OF CONSTRUCTION IN ADDITION TO SUPPLYING A FAIRLY CON—

STANT FREQUENCY CHARACTERISTIC, IS STURDY IN CONSTRUCTIONAND CAPABLE OF

LONG LIFE.

THE CIRCUIT CONNECTIONS FOR THIS TYPE OF PICK—UP ARE EXACTLY THE

SAME AS HAVE ALREADY BEEN DESCRIBED TO YOU IN PREVIOUS LESSONS AND RELA

TIVE TO ELECTROMAGNETIC PICK-UPS IN GENERAL.

VoIumz c=nI-r"oI Ah-‘PL

Y .

/I A  v

I

é:-;I:i:‘. . - l

50: 000.0.

FIG. I6

Crysfal P/ck-up Cannecfforz.

THE CRYSTAL PICK—UP

FRoH WHAT YOU HAVE AL-

READY LEARNED ABOUT PIEZO-EL-

EcTRIc CRYSTALS AND THEIR NUM-

EROUS APPLlCATIONS,YOU WILL

READILY REALIZE THAT IT IS P05

sIaLE To us: sucn CRYSTALS IN

PICK-UP DEVICES, Iu OTHER

wonos, IF THE MECHANICAL VIBRA

TIONS or THE PICK-UP NEEDLE ARE

" TRANSFERRED To A PIEZO-ELECTRIC

caYsTAL,THE CRYSTAL CAN INTURN

GENERATE VOLTAGE CHANGES THE

PAGE I2 souND PICTURES

SAME AS OCCURS IN CRYSTAL MICROPHONES-

THE INTERNAL CONSTRUCTION OF A TYPICAL CRYSTAL PlCK—UP, OR PIEZO-

ASTATIC TYPE PICK-UP AS IT IS FREQUENTLY CALLED, IS SHOWN IN FIG-I5-HERE

' YOU WILL OBSERVETHAT THE

**'§;@,,,;1 Loy Impadancz CRYSTAL AND NEEDLE ARE

I'"¢ MECHANICALLY |NTERcDNNE5

TED THROUGH A "DR|v|Na

’/’/ MEMBER" AND THAT THE CR1

C + bi] /, STAL suRFAcEs ARE CONNEE

vqi a >'

C. TED ACROSS THE OUTPUT

P'¢I"'-‘P \(°\,_,m¢ ¢°,.,\-I-OI TERMINALS OF THE UNIT-

“ *7. -  $225552; i‘"3T2;

p"k'”/D C”””“;"°” MM La”? Lme‘ IMPEDANCE, IT cAN BE EDNN

EcTED DIRECTLY ACROSS THE GRID CIRCUIT or THE AHPL|F|ER'S INPUT TUBE As

sHowN IN F|s.16- THE cHARAcTER|sT|cs or THE CRYSTAL P|CK—UP ARE SUCH

THAT THE FREQUENCY RESPONSE as qu|TE UNIFORM OVER A FREQUENCY RANGE Ex-

TENDING FRDH 30 To 8000 CYCLES. THE AVERAGE VOLTAGE OUTPUT or THE CRY-

STAL PlCK—UP ERDM COMMERCIAL REcoRDs IS ARouND 2 VOLTS. THE NEEDLES REC-

OMHENDED FOR TH|s TYPE or PlCK—UP ARE THE REGULAR HALF—TONE DR TRANSCRl-

PTION NEEDLES.

WHEN THE LENGTH or THE LINE DETHEEN THE CRYSTAL PICK-UP AND THE AM-

PLIFIER rs cDNs|DERAaLE, THEN AN IMPEDANCE MATCHING TRANSFORMER cAN BE

USED IN THE MANNER As ILLUSTRATED IN F|e.1Y. HERE THE PRIMARY WINDING or

THE COUPLING TRANSFORMER SHOULD HAvE AN IMPEDANCE RATING or APPROXIMAT-

ELY_150,OOO OHMS WHILE ITS SECONDARY SHOULD MATCH THE LOW IMPEDANCE or

THE LINE

FDR souND PICTURE

wDRR,As WELLAS FOR EL— +“bI“

ECTRICAL TRANSCRIPTION .

REPRoDucTTDNs,YDu WILL

FREQUENTLY FIND NEEDLE

scRATcH FILTERS EHPLD1

ED IN THE sAHE MANNER

As HAs ALREADY BEEN E5

PLAINED IN A PREVIOUS

LESSON TREATING w|TH

RADIO-PHONOGRAPH cDH-

BINATIONS.

REPRODUCING SOUND Supp¢r¥

FROM THE RECORDS

Now HE ARE READY

To REPRODUCETHE SOUNDS

FROM THE RECORD ANDTHE

sET UP ISCLEARLY sHowN D _A fl1.I".*41:‘ab./$77441!‘-/T5¢‘>*§"£fl'—

IN F|s.18.VAR|ous ARR- p/Efuflz P,-,J"¢,f0,-

ANGEMENTS ARE BEING u;

F!G.lB

LESSON NO 1 PAGE I}

ED BUT IN THE EXAMPLE HERE ILLUSTRATED, THE TURN TABLE IS MOUNTED ON A

STAND ADJACENT TO THE PICTURE PROJECTOR, WHICH IS OF THE CONVENTIONAL

TYPE, OR THE SAME A5 THAT USED FOR THE REPRODUCTION OF SILENT PICTURES-

THE ONLY MAJOR DIFFERENCE 15 THAT THE DRIVING MECHANISM, WHICH HEEL5

THE FILM THROUGH THE PROJECTOR, IS COUPLED T0 THE TURN TABLE AS INDICA-

TED IN FIG~I8, SO THAT BOTH UNITS WILL OPERATE IN PERFECT 5YNCHRQNI5M

WITH EACHOTHER.

THE PICK UP UNIT I5 MOUNTED ON THE END OF A PIVOTED ARM AND AN AD-

JUSTABLE COUNTERWEIGHT IS PROVIDED AT THE OTHER EXTREMETY OF THE ARM,

SO THAT THE NEEDLE PRESSURE UPON THE RECORD CAN BE ADJUSTED-

: u__

As THE RECORD Is ROTA-

TED, THE PlCK—UP NEEDLE

RIDES IN THE GROOVE, VIBRA-

TING FROM SIDE To SIDE IN LmwE5§E¢m

AccoRDANcE wITH THE lRREGU- §:£§:ég§

LARITIES or THE GROOVE, AND

wHIcH You wILL REcALL CORR-

ESPOND To THE SOUND IM-

PRESS|ONS- AuDIo FREQUENCY

VOLTAGES or LIKE FREQUENCY

ARE THUS INDUCED INTo THE

PICK-UP coILs OR GENERATED

av A cRYsTAL,wHIcHEvER THE

cAsE MAY BE. THEsE VOLTAGE

CHANGES ARE THEN APPLIED A-

cRoss THE INPUT TERMINALS

OF AN A.F. AMPLIFIER, WHERE

THEY ARE AMPLIFIED IN THE

USUAL HAY AND FINALLY RE-

PRODUCED As souND av A LOUD

SPEAKER DR SYSTEM OF sPEA§

ERS, THESE SOUNDS,OF COURSE

WILL BE AN ExAcT REFRODUC- 1am£'H‘

TIDN or THOSE wHIcH wERE 05

IGINALLY RECORDED AT THE

TIME THAT THE PIcTuREwAs

BEING PRODUCED. F46; 19

OPERATING OF FILM 5I'mp/Ex Prafecfar‘ WI‘//1 V/es}:/-I1 E/¢cI‘r-fr:

PROJECTOR5 sau/14' Eyu/,1:/#1:/-12.‘.

As You PROBABLY ALREADY KNow, THE FILM FOR A COMPLETE PICTURE Is

DIVIDED INTO REELs OR SEVERAL SPOOLS or CONTINUOUS FILM. CoNsEQuENTLY,

IT Is NECESSARY To CHANGE REELs DURING THE sHDvINe or THE PICTURE AND

To MAKE THIS POSSIBLE IN sucH A HAY THAT THE CHANGE IN REELs I5 NOT No-

TICEABLE TD THE AuDIENcE, Two SEPARATE PROJECTORS ARE HOUSED IN THE PR2

JECTION BOOTH- ONE or THEsE, WITH ITs ACCOMPANYING TURN TABLE FOR RE-

CORD REPRODUCTION IN CONJUNCTION HITH FILM souND REPRODUCTION Is sHowN

IN FIa.19.

ONE or THE PROJECTORS Is THROHING THE PIcTuREs UPONTHE SCREEN WITH

THE ACCOMPANYING REEDRDIND AND DURING THIs TIHE,THE FDLLDVIND REEL I5

THREADED INTD THE SECOND PROJECTOR, vHIcH Is THOROUGHLY PREPARED To BE

PAGE III soum: PICTURES

SET INTO IMMEDIATE OPERATION- THE SAME IS TRUE WITH RESPECT TO THE FOLL-

OWING RECORO. THEN AS THE FIRST PROJECTOR FINISHES SHOWING ITS REEL,THE

SECOND PROJECTOR IS PUT INTO OPERATION,TAKING UP THE SHOWING WHERE THE

FIRST LEFT OFF. THE END OF THE FIRST AND THE BEGINNING OF THE SECOND

REEL ARE S0 MADE AS TO OVERLAP AND THE PICTURE FROM THE FIRST REEL FADE5

INTO THAT OF THE SECOND REEL S0 THAT THIS CHANGEOVER IS NOT NOTICEABLE

TO THE AUDIENCE.

As THE szcouo PROJECTOR mass oven nrs DUTI£S,TI-IE FIRST PROJECTOR

|s SHUT oowu mo "THREADED" FOR 1-|-as "re-nno REEL mo IT mu. courmus

wnsm-: THE sacouo LEAVES OFF arc. Tms PROCESS IS courmuzu UNTIL THE

cm: or THE PICTURE mo TO nae AUDIENCE, THE PICTURE APPEARS 1-o as ans

coN'r|Nuous FILM.

AT THE END OF A RECORD, THE MUSIC OR SPEECH COMING FROM ONE MA-

CHINE MUST BE BLENDED UNOTICEABLY INTO THAT FROM THE OTHER, JUST AS THE

PICTURE FROM ONE REEL IS FADED INTO THAT OF THE FOLLOWING ONE- TO ACCQM

PLISH THIS, YOU WILL FIND THAT AT THE END OF EACH RECORDING DISC, THE

MUSIC OR SPEECH OVERLAPS THAT AT THE BEGINNING OF THE NEXT AND A FADER

MAKES THIS CHANGEOVER IN SOUND EFFECTS POSSIBLE WITHOUT BEING PERCEPTI-

BLE TO THE AUDIENCE-

AS THE STARTING PROJECTOR GOES INTO OPERAT|ON,THE FADERKNOB ISTUE

NED AND THE ENERGY DELIVERED T0 THE AMPLIFIERS IS CHANGED QUICKLY un-

TIL IT COMES ENTIRELY FROM THE NEW‘RECORD- THE FADER ALSO SERVES AS A

VOLUME CONTROL AND THUS PERMITS AN ADJUSTMENT WHEREBY IT MAKES IT POSS

IBLE TO EQUALIZE THE LEVEL OF SOUND AS OBTAINED FROM THE DIFFERENT REC-

ORDS THE FADER OPERATES THE SAME A5 SHOWN YOU IN YOUR AMPLIFIER

SERIES.

THE PROBLEM OF SYNCHRONIZING THE RECORD TO THE PROJECTOR IS QUITE

GO\/¢I"\'\OY'_

F I G . Z0

An AI/zLeri1;/'/mg Clrr-¢»11‘ Dr/vz Mafar Cb/1»-rec fed

74¢ -//rz E/ecf»-/'¢ O/ozra/'eJ Ga var/wrz

6. -

EXAMINATION QUESTIONS

LESSON N0. SP-I

or every piece produced by

a master is necessarily a masterpiece.

J» A. RQSENKRANZ

WHAT |s A "RECORDER" AS uszo IN THE MAKING or DISC RE-

CORDINGS FOR souun PICTURES?

IN THE MAKING or onsc RECORDINGS, as IT THE GENERAL

PRACTICE To MODULATE THE RECORD enoovs av VARYING ITS

DEPTH?

Is IT POSSIBLE To REPRODUCE THE souuns DIRECTLY FROM THE

"wAx" IMMEDIATELY AFTER IT HAS BEEN cuT?

HHAT IS A "MA5TER",A5 USED IN THE MANUFACTURE or RECORDS?

BRIEFLY DESCRIBE THE FUNDAMENTAL OPERATING PRINCIPLES OF

AN QIL—DAMPED PHONOGRAPH PICK—UP UNIT.

How ARE THE TURN TABLE AND FILM PROJECTOR GENERALLY KEPT

SYNCHRONIZEDT

OF WHAT usE IS THE "FADER" WHEN suowunc souno PICTURES IN

A THEATER?

DOES THE PITCH OF RECORDED SOUND BECOME HIGHER OR LOWER

AS THE SPEED OF THE TURNTABLE IS INCREASED?

DESCRIBE THE STRUCTURAL FEATURES OF THE CRYSTAL-TYPE HWNO

GRAPH PICK UP-

DESCRIBE THE VARIOUS STEPS NECESSARY IN THE RECORDING OF

SOUND ON DISC-