US2405246A - Sound recording system - Google Patents

Description

ama@ E. F; WATSLQN SOUND RECORDING SYSTEM sheets-sheet 1 Filed May 21, 1943 Q WIS* 256M.

TTONEY www Aug. 6, I

' E. PWM-SON SOUND RECORDING SYSTEM Filed Mayv 21, 1943 5 Sheets-Sheet 2 E. F. ATSON SOUND RECORDING SYSTEM Filed May 21, 1943 3 Sheets-Sheet 3 /Nl/EA/Ton Ff @A T5 Patented Aug. 6, 1946 SOUND REconDiNG SYSTEM Edward F. Watson, Larchmont, N. Y., assignor to l Bell Telephone Laboratories, Incorporated, New

York, N. Y., a corporation of New York Application May 21, 1943, Serial No. 487,890 l This invention pertains .to the 'recording of sound and more particularly to the recording of sound on film for use inconjunction with motion picture `iilm. More Specifically the invention pertains to the production of av control corresponding to the volume variations of sound as said sound is varied in the production of sound lm.

` An object of the invention is the improvement of controls employed to reproduce variations in Sound volume in the manufacture of sound film.

In the sound motion picture industry at the present time it isthe v,practice to combine the sounds produced in a number of sound sources into a single sound record. For instance, a record of the speech sounds occurring during the filming of a sequence will have added to it other sound effects such as music, etc. The picture film is projected and the various sound effects are integrated into a single sound tract at a rehearsal or a number of rehearsals. The volume of the sound from the separate sources is adjusted manually by an attendant or a number of attendants who operate controls, such as potentiometers or other volume controls, on what are known as sound mixer panels. Until recently, when it was foundnecessary to modify a sound track into sclaims. loins-100er n which sound from a number of sources has been integrated. there were no means other than the memory and experience of the mixer attendants for reproducing exactly the original control settings and there was no record of such settings which might have been used as a reference for changes found necessary in the volume of the sounds from the various sources.

Recently means have been provided in the art for improving this situation. Record is made of the patent to Wolfe, 2,279,018, April 7, 1942, which provides a magnetic tape record of the control settings which is used to reproduce the settings,

Experience has shown that the magnetic tape method of reproducing the settings of sound volume control apparatus is not entirely satisfactory.

r The invention herein affords certain advantages over presently known arrangements, among the most important of which are its accuracy, its stability, and its economy and even more important, its ease of 4operation and its simplicity, as compared with presently known devices for performing the same function.

A feature of the invention is apparatus for translating control settings into permutation code signals which are recorded aspunchings in a continuous tape. The tape is thereafter used to reproduce the original settings of thel control instrument..

The invention may be understood from the following description when readvwith reference to the drawings in'which: .y Fig.,1 discloses the means for translating each of thirty-two settings of .apotentiometer or volume control intoa different one of thirty-two vdiiferent code combinations .of contact settings in accordance with a five-elementpermutation code. It includes a circuit by means of which the permutation eode signals, are impressed on a set of five magnets which set in turn controls a set of live punches in a tape perforating device. Permutation code signals corresponding to the setting of the control instrument'are thus punched in a continuous tape... 1 l -v Fig. 2 is an arrangement for retranslating the permutation code signals punched .in the tape produced in theappar'atus per Fig. linto settings of a Sound volume control device.

Refer now to Fig. 1. A sound head I compris-l ing a sound track 2 and an electro-optical system, not Shown but well known, is shown at theupper left of the figure. Electric currents corresponding to the variations in the sound track are impressed on amplifier 3. 'I'he full voltage of the output of amplifier 3 is impressed across the full resistance of potentiometer 4. Rotatable contact arm 5 of potentiometer 4 impresses gradations of the full voltage on amplifiers 6 and 1 in parallel, the out-.- puts of whichare connected respectively to ,a monitoring sound reproducer 8 Aand a sound recording device 9. Multiple branches 8l and 82 extend from the connections to the inputs of ampliers and 1. These connect to Potentiometers such as 4 in as many other Sound sources as are being integrated into a single record It is emphasizedthat any number of sound'sources without limit may be connected to a single recordel', Arm 5 is controlledvby knob Il) through shaft ilV to which shaft the knob I0 and arm-5 are rigidly secured. Rigidly secured also to the shaft Il are live cams I2 to I6. The cams I2 to i6 are conditioned to actuate their followers to control contacts I1 to 2l respectively. Rotatable arm 5 is conditioned to be rotated through anarc of 270 degrees.. The arc is divided into thirty.- twn ecual segments. The cams |2.to I6 are cut in a manner to provide thirty-two di'erent permutative settings of contacts l1 to 2| each corresponding to a different oneof the thirty-two segments. .The control knob IB is operated manually to vary the settings-of .potentiometer armv 5 yand thus to regulatethe input into ampliers and] which are connected'across Athefoutput of theY potentiometer. The volume of the sound is repermutatior'i codes punched in the tapel |0 which is, the tape .44- modified asv desired. The tape H is drawn oi supplyreel by a sprocket inthe tape transmitter driven'from lmotor |2` synchronous with `motor drive for lsound head |00, and wound on a take-upv reel, not shown, secured by suitablegearing to shaft |20. `When switch ||3 is closed power is supplied from power source H4 to motor H2 and the winding of magnet H5 in parallel.'` Normally` the transmitter feed sprocket is driven from a cam on shaft |20 and isprevented from'rotation by means of the-righthand end of armature'lever H6 whichis interposed in the path of a projecting shoulder on cam ||9 rigidly securedto shaft |20. Spur gear |2| is rigidly secured to shaft |20 and engages worm gear |22 which is connected through friction clutch |23'to motor H2.;

Magnet when energized attracts the lefthand end of lever magnet H6 rotating it in a clockwise direction about fixed pin H1 against the inuence of `spring I8. The right-hand end of lever is thus disengaged from the shoulder on the periphery of cam ||9,'permitting shaft |20 to rotate. g n '7 Tape |0 is drawn over iive sensing pins. Where any of the ve lateral positions in a transverse section of tape I |0is punched a sensing pin in a corresponding position is admitted through the opening and a corresponding one of contacts |24 to '|28 is closed in a well-known manner. circuit may thereupon be traced from battery |29 through such of the contacts |24 to |28 as are closed and thewindin'gs of the corresponding relays I 05 to |09 operating the corresponding relays. The contacts of relays |05 to |09 will be closed in various patterns to establish a diierent one of each of thirty-two paths through the relay contacts for each'of the thirty-two different code combinations which may be punched in the tape H0. Whenever a relay is operated it is locked over a path which may be traced from battery |30 through resistance |3| and contact |32 which is connected in parallel to an armature on each of relays |05 to 09 which cooperates with a locking contact on each of these relays to extend the path through the relay winding to ground. Contact |32 is under control of cam |33. The cam is arranged so that once in each revolution contact |32 is opened for a short inr..

terval, thus unlocking those of relays |05 to |09 which may have been operated by the particular code combination for an interval just sufficient for them to release so that the relays may respond to the next code combination. This inter- .7'.

val is timed to correspond with the stepping of the tape from one code combination to the next.

The bottom terminal of amplier |0| is connected to the bottom terminal of potentiometer |02 and the bottom terminal of amplier |03. The top terminal of amplifier |0| is connected to the top terminal of potentiometer |02. of the thirty-two taps connected to the junctions of the resistance elements of potentiometer |02 extends through a different path through the contacts of relays |05 to |09 to conductor |34 which connects to the top terminal of amplifier |03. When relays |95 to |09 are each in the released condition, as shown in the drawings, upper conductor |34 extends through contacts |35, |36, |31, |38 and |39 to junction point |40 of potentiometer |02. If relay |05 is operated and relays |06 to |09 are released, a circuit may be traced from conductor |34 through contacts |4|, |42, |43, |44 and |45 to junction point |46. If

Each Y relays |05 'and' ,I 00 are .operated and4 relays |01 to |09 are released, a .circuit maybe traced from conductor |34 through contacts |4|, |41, |48, |49 and |50 to junction point |5|. For each one of the other taps of potentiometer |02 there is a single selecting path'extending `through the relay contact fan circuitwhich is closed through the operationjof the proper combination' of re-flays|05to|09;' l, It has been pointed out above thatthe final sound track is ordinarily made bycontrollin'gthe volume of sound Lfrom a number ofsources." Any number of separate sources may be employedfor this purpose. I The mechanism which has been described'in detail is arranged to provide a record of the `vari-y ations in the volume of one sound source only. If more than one source is employed, which will almost invariably be the case, it will be necessary to provide a separate mechanism such as has been described for the production ofv a record corresponding to the variations of each sound source. .Attention is'particularly called tothe fact. that a. separate tape, such asY 44, is prepared to record the potentiometer or .volume control settings of each potentiometer or volume control which controls the output of the sound from each sound head, such as which is connected -to recording head 9. .The multiple leads 8| and 82Y which connect to the input of the common sound reproducer 8 and common sound recorder 9 are multipled to as manyseparate potentiometers, such as 4, as there are separate sound heads, such asv Voltages'corresponding tol thev combined sounds are impressed on the inputof ampliiiersi and 1. An individual record of the settings kof each potentiometer, such as I0, is recorded simultaneously inv separate tapes, such as 44, by means of an individual tape perforating mechanism controlled by an individual set of permutation cams and contacts for each separate sound source.

If it is found desirable to modify the sound recording produced by the mechanism of Fig. 1, such of the individual tapes corresponding to 44 as are unsatisfactory are modified as desired. Then the original' sound tracks usedy in, preparing the original tapes are run through their respective sound heads. This time instead of connecting each sound head through a manually adjusted potentiometer, such as 4, to the recording head, each separate sound head is connected through a potentiometer, such as |02, which is controlled by a relay fan circuit in response to the modified codes in its respective tape.

Only one sound head and its associated tape controlled potentiometer are shown in detail. C'onductors |34 and |60 which interconnect potentiometer |02 associated with sound head |00' and the common recorder |04 are multipled through conductors |10 and 1| to other potentiometers, such as |02 and |00, each of which is individually controlled by its respective tape, such as H0, and its own individual fan relay circuit Y corresponding to relays |05 to |09.

An amplifier |12 and a sound reproducer |13 serve for monitoring the production of the final sound record.

If it is desired, a permutation code of a larger number of elements may be used to provide finer adjustment. It would also be feasible to set a single group of a larger number of contacts permutatively to integrate the settings of a number of volume controls and thus provide a punched Vtape in which a single code having a larger esonera number of I *Y lements y.defines.thesettingfof allfof` the.petentiometers.,simultaneously.- yWl-iat isclaimed is: f ,.V ,i 1, .}Inl valso'und recording system, means for varying sound volume, and means controlled in accordancegwith successive sound varying -acljustrnents ,of said rst named f means for providng a visible permutation code record of said Ysound volume'V so varied, said record comprising visible permutationvcode combinations, at successive equal interiials, `each individual combination corresponding `tothefull amplitude Vof said volunie `so lvaed,v to facilitate the V.reading inter. p'r'etation and modification of said record.

`2. Inasound recording system, a volume contrOI, means for varying the settings of said volunie control, and means directly responsive to the operation' of saidy varying Vmeans for perforating permutation code signals defining said variations inatapef f3. In Lasoun'cl recording system, Qa sound track, ar sound' 'reproducerl connected thereto, a sound volurnecontrol intermediate said 'track and said reproducen means for varying tnefsettings of said controlmeanswf/or recording a Icontinuous series o'f permutation 'code signals defining said sett'ings, said last means comprising a continuous tape,` separate/from said track, said tape having code lcombinations corresponding to said settings visibly impressedthereon yat' snort equally spaced intervals.V 'K ,i

4. Tn a sound recording system, 'a .sound track, a. lsound reproducer, "means intermediate said track, and saidreproducer 4for varying the volume of sound, means responsive' to said variationsfor permuta/tively controlling ya plurality of contacts, and means Vconnected to said contacts vfor producing'a visible permutation code record having a sequence )of permutation codesV each representing a volume, of ,sound characteristic of a ,smallmorvV tion -of saidtrack. K 'l l v A .r5. jrl2n` afsoundfrecordingsystem, ,a sound .track recorded upon a medium, f ia sound vreproducer, means intermediate said :track and said repro-v ducer for varying the volume of sound, and means responsive to changes in thesetting of said sound varying vmeans for producing .a visible v.rer'zordof said settingsdn a medium separate from said sound mediumsaidrecordbeing a succession of permutation code combinations of visible elements, eaclrof said, code combinationscorrespondingftova particular setting of ysaid vary!v ing means. Y Y .i l

' V6. In a sound recordingsystem, a soundtrack, a sound reproducer, a sound ivolume conifrOLin-vr termediate said track and vsaid reproducer, for varying the volrune of sound,a setfofcamsfaset of contacts controlled bysaid cams, means'for varying the setting of said volume control,` and means for controlling said contacts so as to set up a multielement permutation code signal-'cor-` responding Pto settings of said volume control...-

157. In asound recordingtsystemta sound track, a sound recording device, a volume control iti-1 termediate said trackand said device, a medium, a succession-sof;'permutation code combinations of visible conditions 'in `said medium, and means capable of -assuming successive permutative conditions under control v,of'said medium for selectively :setting said -volume control in accordance with said conditions. Y i

8: An, elongated flexibleV medium, a sound volurne control, and means directly responsive to.

changes i-nrthe'fsetting of said control for physi-l cally impressing said medium with successive permutation code :combinations representing sound volumes. v z l f v EDWARD F. WATSON.-y

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