FRAYNE HISTORYOFDISKRECORDING

new electromagnetic rubber-line re- give better reproduction of the shorter The next historic step in recordingcorder is given in Fig. 4. The instru- wavelengths at the slower groove development was made by Bellment is essentially a three-section velocities. This system was first used Telephone Laboratories in the earlymechanical filter with which the re- commercially in the production of the 1930s. A completely new system wascording stylus and its holder consti- feature "Don Juan" in 1926. Only the perfected incorporating the followingtute the series mass in the second music score was recorded. In 1927 [4].

section. Since a filterofthis type ap- "The Jazz Singer" was produced, 1) A vertical-cut recorder usingpears at its input end as a pure resist- also by Warner Bros., using the trade electrical feedback was to eliminateance within the transmission band, name Vitaphone. The parallel intro- mechanical resonance. A schematic

the velocity of the series mass is pro- duction of a film sound track by ERPI representationoftherecorderis shownportional to the driving force. In in 1928-19291ed to the abandonment in Fig. 11. Fig 12 shows a flat re-practice it is not feasible to have of the synchronized disk system circa sponse up to 12 kHz, the mechanicalconstant velocity over the entire fre- 1932. resonance having been eliminatedquency range. Since the amplitude of

the lateralcutvariesinverselywith _ _ Y_frequency,leading to abnormally _ _ __widegroovesatthelowerendof the _ _ _spectrum, equalization is introduced

at the low end to provide an essen- =.......C:>t__0 v-- tel _ Z

tially constant amplitude recording. _:_ _c.o _= _ _ _F--"_ .J Z _ ._ _ t,J

Fig. 5 showsan earlyelectricre- < <_-......

corder, usinga continuousrubber- _,, -_oI _, _' I A_ Iline filter, which provides an essen- _ ff000000,___y-r._____000000,T---_000000,-_tially pure resistance at the input end.

ELECTRIC

Fig. 6 illustrates the mechanical filter UNS ___ c,_ c,_ _,of the recorder, while Fig. 7 showstheresponseforvariousconstantsof -

the system. Fig.4. Equivalentelectriccircuitoftheelectromag-The next step was the development netic recorder. (After Maxfield and Harrison [1].)

of a matching mechanical reproducer.A diagrammatic sketch is shown inFig. 8, and the equivalent electriccircuit is given in Fig. 9.

The success of the new recorder

encouraged the Western ElectricCompany, which had taken over thecommercial exploitation, to adapt itfor talking motion pictures, withsound being reproduced by a.syn-chronous disk reproducing system.Certain basic changes were made forthis system. A rotation speed Of'3_3V3

r/min was adopted in place of the old78 r/min. A 16-in (405-mm) diameter

Fig. 5. Inverted view of the electromag-disk was employed, and the film netic recorder, complete except for cover Fig. 6. Detaileddrawingofthe mechan-speed was increased from 16 to 24 over rubber line. (After Maxfield and ical filter of an electromagnetic recorder.frames per second. The first 33]/3- Harrison [1].) (After Maxfield and Harrison [1].)r/rain disk recording machine wasdeveloped by Western Electric Com- __ 1 ?___ _9tv_]___,o__v_

I -- - -_'_' N AL¥.ONSTNi'S

pany.^ mechanicalfilterwasem- I Zployed to filter out irregularities in the ,_F/-_P_ - ---_--motion of the mechanical drive sys- _---_,;-._,;TJz_-- t I'/_:"_"-? _[_

tern. Fig. 10 shows the Un ivers al _o_' :_[ ¢:-i_"", _--_ij/_ ._--x. _--

Base theater reproducer, with thedisk >turntablemountedontherearof the ' ': ....

projector. Asteel needlewas used in ......reproduction, the recording being _._._done from the inside out. This im-

Fig. 7. Velocity response for various values ofproved the sound quality of the inner mechanical constants. (After Maxfield andgrooves since a new needle would HarrisonIll.)

264 J.AudioEng.Soc.,Vol.33,No.4,1985April

w

C_, .-C. _ _: _

c..? _o8 ___,.o __ ,, 8 _

>- _ _ uJ > ,.a z - o _ ac

T/-! ....c, _ .............

'- 2'!!!! ?'Fig. 8. Diagrammatic sketch of the me-chanical system of the Orthophonic pho-

nograph. (After Maxfield and Harrison Fig. 9. Electrical equivalent of system of Fig. 8.[1].) (AfterMaxfieldandHarrison[1].)

Fig. 10. Western Electric theater reproducing equipment incorporating the so-called "Universal Base," which carried apparatus for reproducing both disk andsound on film.

,_o,, _ I Ill i.l;'i_!lt ',,'° ilI_Hjll___i_l_h.liJJ"{ I

D"'"'"° __i i nlh,[il!lHIJ ', ,

· _ G!?F,'i !!!lFii'i_! ',,{

' _' I !li;l-J_l-]-I 17_1 t '-'i,i !7<[Rllli {l{q-_[{ ,1,_ _'1 ! !!lllLI ......._......I I Ih_.

ioo iooo iooooCOiL r_EOU£NCY /N CYCLES P£_ &ECONO

Fig. l 1. Cross-sectional view of feedback vertical re- Fig. 12. Frequency response of vertical recorder with andcorder. (After Frayne and Wolfe [5].) without feedback. (After Frayne and Wolfe [5] .)

d. AudioEng.Soc.,Vol.33, No.4, 1985April 265

FRAYNE HISTORY OF DISK RECORDING

entirely, studios, and the Hollywood ERPI in the pressing. This defect could be2) Flowed hot wax disks were used disk processing lab was flooded with overcome by rerecording the dis-

in placeofthelargewaxplates, work. Dick Fullerton was put in torted curve with reverse polarity3) Gold sputtering of the recorded charge of this operation. Later he with the same circular stylus tip. Fig.

wax was used in the plating process, became chief engineer of the World 16 shows curves of distortion versus

(4) Pre- and postequalization were Broadcasting Company, which pro- frequency for various recording con-used to increase the signal-to-noise duced vertical-cut transcriptions until ditions, which appear to favor theratio, the adventof magnetic tape. lateral-cut approach. The introduc-

(5) Acetate pressings replaced the Despite the high quality of the Bell tion of magnetic tape recording fol-old shellac disks. Telephone Laboratories vertical-cut lowing World War II effectively

The recording and reproducing system, the older lateral-cut records ended the use of the electrical tran-

characteristics are shown in Fig. 13. continued to be widely used. A paper scription for broadcast.The large amount of preequalization by Pierce and Hunt, in the journal of Two historical developments tookand subsequent postequalization in the Society of Motion Picture Engi- place in the late 1940s. In 1948 CBSthe upper frequency range contrib- neers [7], appeared to give an unfa- introduced, with much fanfare, their

uted to the high signal-to-noise ratio vorable comparison when the vertical long-playing records with a capacityof these records. Subsequently an cut was compared to the lateral tech- of around 250 grooves per inch and aindustrywide search for standard re- nique. Fig. 15 shows the distortion playing time of 20 to 25 min. The ra-cording and reproducing character- introduced by the circular stylus tip as dius of curvature of the pickup was onistics resulted in the reproducing it passes over a cosine curve recorded the order of 0.001 in (0.025 mm).curve of Fig. 14.

The system was introduced on anexperimental basis in Hollywood,notably at Columbia Studios, wherethe original recording of One Night of 1

Love with Grace Moore won the ..--[-4. .. .--- . . _. .; . X_......_ _'Academy Award for best sound. Thiscaused a flurry of interest in other _ _ T,^CEO ,

74:4.5 c?.

Fig. 15. Recorded curve and curve traced in reproduction.(After Pierce and Hunt [7] .)

4C

40 '00 _00 400 'kilt 2kHz' 5kHz'Ok:'z { I I-I I[II R_&oJ' I I/11II/,' I

:;LJL!' "0ii' I!ltlf/, ig.,..eco di. and..od i.gcha ac,eristic, orve ica,::? : _" 'V/records.This is the standardcharacteristicusedin 1953,when _ _ 0osuch records were still in use. Each major vertical division is _, . 3oo_ //AMPLITUD£--0002 · g_.

5dB.(AfterTremaine, Audio Cyclopedia [6].) _zo-- I IIIII1:/'1 71¢41111'/ I,o .2¢-I' 1] I_,t_I I

: _ ', _ t I _'1tl/11+10 . : o 78 RRM ,_" ,I IlJIl}+5 ---

o v.,,c_-./ ::=,}_/ll[t /o //

1 ] IIIII/ |

20 _--_-- --- --_ -- ) ) I 14---1--t_ |- I I 1 I It-f''_''_ -1 I

100 200 500 I000 2000 $000 100(30 200(3020 50 IOO 200 500 IOOO 2OOO 5O00 IO,OO0 20,OOO

FREQUENCYIN HERTZ FREQUENCY IN CYCLES

Fig. 14. NAB (RIAA) standard reproducing characteristic. Fig. 16. Curves of distortion versus frequency for various(After Tremaine, Audio Cyclopedia [6].) recordingconditions. (After Pierce and Hunt [7].)

266 J.AudioEng.Soc.,VoL33,No.4, 1985April

/

About one year later RCA announced Blumlein of EMI was granted the 107 years. It again illustrates how atheir 45-r/min system. This utilized British patent 394,325 on a two- simple idea by a single individualthe microgroove technique but had a channel stereo system. He called at- becomes transformed over the yearsmuch shorter playing time of around tention to an orthogonal 45-45 sys- by others utilizing new techniques5 min. It employed a large center hole rem as an alternative to a vertical- and new materials into a medium ofof approximately 1.5 in (38 mm), lateral system. At Bell Telephone almost perfect reproduction of thewhich ensured a more accurate cen- Laboratories Keller made stereo rec- human voice and a wide miscellany of

tering of the record on the turntable ords as early as 1936, and was granted musical instruments and sound-pro-

with resulting improved quality of U.S. patent 2,114,471m, which also ducing devices. We can only wonderreproduction. This was a well-de- discloses a 45-45 alternative to the what the twenty-first century has in

signed system, but the short playing vertical-lateral system. There was no store for us.time gradually reduced its appeal to followup by the Westrex Corporationthe general public. The CBS system to the earlier Bell Telephone Labo- REFERENCEScontinued to be the standard method ratories until circa 1957, when ru- [1] J. P. Maxfield and H. C. Har-of recording until the introduction of mors of stereo disk developments in rison, "Methods of High Quality andstereo records in the late 1950s. Britain and Germany forced Westrex Reproducing of Music and Speech,

The final phase of this presentation into a crash program to develop a Based on Telephone Research," Bellwill deal with the development of the stereo disk system that could give the Sys. Tech. J., vol. 5, p. 493 (1926stereo disk system. In the early 1930s same quality of sound in each chan- July).Bell Telephone Laboratories [8] were nel. A preliminary sketch for the de- [2] O. J. Zoble, "Theory and De-experimenting with what was known sign of a stereo disk recorder illus- sign of Uniform and Compositeat the time as acoustic perspective trated the difficulties involved in a Electric Wave Filters," Bell Sys.sound reproduction. They found that vertical-lateral combination. Be- Tech. J. (1923 Jan.).a three-channel system of recording causeofthisproblemandthedesireto [3] E. C. Wente, "ElectrostaticTransmitter," Phys. Rev., vol. 19and reproduction gave satisfactory obtain comparable quality in both (1922).spatial and depth reproduction of the channels, the orthogonal 45-45 [4] L. Vieth and C. F. Wiebusch,original orchestral music. They found system evolved [9]. A patent search "Recent Development in Hill andthat a two-channel system gave some- revealed both Blumlein and Keller Dale Recorders," J. SMPE (1938what inferior results. Later they de- patents covering this system. A sim- Jan.).veloped a three-channel film record- ' plified schematic of the stereo re- [5] J. G. Frayne and H. Wolfe,ing and reproducing system which corder is given in Fig. 17. Fig. 18 Sound Recording (John Wiley andwas demonstrated in 1939. The term shows a cross section of 45-45 Sons, New York, 1949).

"stereophonic" had been adopted by grooves for limiting conditions. The [6] H. M. Tremaine, Audio Cy-this time. It is not generally recog- feedback circuits were applied for clopedia (Howard Sams and Co. Inc.,nized that considerable research was each drive assembly, thus giving the Indianapolis, 1969).carried on in the 1930s on a method of same resonance-free response as in [7] J. A. Pierce and F. V. Hunt,"Distortion of Sound Reproductionstereophonic disk recording in which the earlier vertical recorder, from Phonograph Records," J.two channels were recorded in a sin- This has been a brief review of the SMPE, vol. 31, p. 157 (1938 Aug.).gle groove. For example, in 1933 disk recording history over a span of [8] H. Fletcher, "The Stereo-

phonic Sound-Film System," J.SMPE, vol. 37, p. 331 (1941 Oct.).

[9] C. C. Davis and J. G. Frayne,

.__' "The Westrex Stereodisk System,"

Proc. IRE, vol. 46 (1958 Oct.).

5. -- · N'

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/ I _[ND POLEPIECr

/ ( J ......... -' '"_------'_" // '" _ xCOPPER RING "x\X,v,_./z'x_, .- z xx' /

_ %. 'x.__ ' '_: ' vi- :)x.'_,._,_' .,[ v7-% .. _ ._ xx i! x J

V"_'

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MAXIMUM GROOVE EXCURSION

. 2.0+24 2D+,2,_

RELATIVE OUTPUT PER CHANNELA VT

TYU5 L _ ''_ COIL SUPPORT ''j' HOT STYLUS _/ -_STYLU$ SUPPORT RELATIVE DB PER CHANNEL$pRiI_G5 WIRE MEMBER 0 --3.0

Fig. 17. Simplified illustration of mechanical construc- Fig. 18. Comparison of 45-45 with standard long-playingtion of stereo recorder. (After Davis and Frayne [9].) lateral groove. (After Davis and Frayne [9].)

d. Audio Eng. Soc., Vol. 33, No. 4, 1985 April 269