US1994920A - Sound recording system - Google Patents

Description

March 19, 1935.

W. M. PATTERSON SOUND RECORDING SYSTEM Filed June 11, 931

2 Sheets-Sheet l jive/away WITN ESSES I INVENTOR William MPaffersa/r.

ATTO NEY March 19, 1935. w, M. PATTERSON 1,994,920.

SOUND RECORDING SYSTEM 2 Sheets-Sheet 2 Filed June 11, 1931 WITNESSES: INVENTOR William Pai'frsofl. 9g "14 ATTORNEY Patented Mar. 19, 1935 emanates PATENT orr ce SOUND RECORDING SYSTEM Application June 11, 1931, Serial No. 543,507

12' Claims.

graphic apparatus and has particular relation to apparatus of a type wherein a directional effect is introduced into the sound reproduced with a motion picture that corresponds to the elements of the picture that are shown sound.

In acousto-cinematographic apparatus conto produce the structed and operated according to the teachings of the prior art, of which I am aware, the sound is reproduced from a plurality of loudspeakers disposed adjacent to the screen in with some prearranged scheme. The

accordance loudspeakers are, at any instant, all energized to the same extent and. in consequence thereof, emanating from the region of the scr property of homogeneity in direction.

the sound can has the The points on the screen from which the sound should emanate vary as persons depicted appear tomove across the screen. an arrangement is rather strange an even ludicrous. Moreover, when a The effect produced bysuoh d, at times, number of persons are portrayed as speaking simultaneously, the result is rather confusing to the audience, since the sounds that are shown as coming from the characters cannot be distinguished.

It is, accordingly, an object of my invention to provide acousto-cinematograp'hic apparatus wherein the sound reproduced shall rectional characteristic.

have a di- Another object of my invention is to provide acousto-cinematographic apparatus wherein the sound produced shall emanate from a screen corresponding to the position ture element by which the sound is produced.

A further object of my invention is acousto-einematographic apparatus wherein the elements of a picture from which a plurality of sounds are apparently region of a of the picapparently of a type emanating shall be distinguishable by reason of the direction in which the sound is actually being projected.

A specific object of my invention is to provide a recording device of a type wherein a record shall be impressed on a permanent.

medium in such manner that the relative disposition of the elements from which the original soun shall be distinguishable.

d emanated recorded was projected.

A still further specific object of m y invention to provide My invention relates to acousto cinematois to provide cine-acoustic recording apparatus of a type wherein the recording elements shall respond to the relative disposition of the objects fromwhich the sound to be recorded is emanating.

Still a further specific object of my invention is to provide reproducing apparatusof a type wherein the sound emanating from a given region shall have a predetermined heterogeneity in direction.

Another specific object of my invention is to ,0 I

provide reproducing apparatus of a type wherein the sound emanating froma given region shall have a heterogeneity in direction that shall be so variable with respect to time as to correspond to the picture projected. Y

.Still another specific object of my invention is to provide reproducing apparatus to be utilized in an acousto-cinematographicj system of a type wherein the sound reproduced shall emanate from regions predetermined by the disposition of the elements in the recording setting.

An incidental object of my'invention is to provide a sound record particularly adapted to be utilized in directional acousto-cinematographic apparatus. V

A further incidental object of my invention is to provide a sound record of a type having a property whereby the directional efiects of sound shall be capable of being recorded.

1 Another incidental object of my invention is to provide a photo-sensitive device particularly adapted to be utilized in directional cinemaacoustic reproductions Still another incidental object of my invention is to provide a photo-sensitive device to respond to localized excitation in a predetermined manner.

A still further object of my invention is to provide a photo-sensitive device that shall be capable of responding to localized excitation in a manner that shalllend itself to the spacial prearrangement of elements energized by the device. 7 f

More concisely stated, an object of my invention is to provide reproducing and recording apparatus of atype that shall cooperate in produc-. ing acousto-cinematographic entertainment wherein the elements of a picture from which a sound appears to emanate shall correspond, in a natural and expected manner, to the original source of-such sound.

According to my invention, a plurality of de- Vices for translating acoustic disturbances in the air into electrical energy,; such as microphones, are disposed in a predetermined manner in the vicinity of a setting to be photographed and 55 recorded. The sound impressed on the microphones is amplified and the outputs of the amplifiers feed into the exciting element of a light valve of a type, well knownin the art, such as a recording galvanometer or a Kerr cell.

At a predetermined point in each recording amplifier, certain of the translated electrical energy-is tapped oif and is fed into an averaging device.

The averaging device has a balanced structure and is responsive to the difference in the mag-nitude of the energy fed to itfrom the individual amplifiers. The output of the balanced averaging device feeds into an exciting coil that regulates the position of a galvanometer mirror, and the mirror is thereby deflected in a direction corresponding to the predominating amplifier. The magnitude of the deflection corresponds to the average energy impinging on the sensitive element of the microphone corresponding to the predominating amplifier.

The recording light beam is modified by the light valve and is deflected .by the mirror in a manner predetermined by the condition of the sound-translating devices and their corresponding amplifiers. A rectangle is thus imagedlon a film strip that has a width large in comparison with the long dimension of the rectangle, and the lateral position on the film at which the rectangle is imaged corresponds to the position of "the most highly excited microphone- That is to say, the position of the sound track' on the film corresponds to the position of the object from which the sound of maximum intensity is being emitted.

When the film thus energized is printed and developed, a record is produced wherein the sound track has a lateral variation in position which corresponds to the variation in position of the bodies in the recording setting that originally emitted the sound.

The record is reproduced in a manner well known in theart. That is to say, an attenuated light beam is projected on the film and is modifie'd in 'accordancewith the character and-disposition of the sound track. After being modified, the light impinges on the photo-sensitive elements of an elongated photo-sensitive device particularly adapted for the present purpose.

The photo-sensitive device prefer-ably comprises a plurality of photo-sensitive electrodes and a plurality of collecting electrodes associatedtherewith. The collecting elements are dis* posed adjacent to the photo-sensitive elements and the electrodes are connected in independent circuits in such manner that energy is transmitted to the circuits inaccordance with' the locali- Zation of the light beamexciting the element.

The circuits into which the photo-sensitive electrodes feedare connected to independent amplifiers which, in turn, feed into "independent loud speakers disposed adjacent to picture-reproducing screen in a manner corresponding to the original disposition of the microphones adjacent to the photographing stage. The amplitude of the sound produced in the loud speakers corresponds to the lateral disposition of the sound track on the film and, therefore, corresponds to the original disposition of the objects emitting the sound. a

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and .its method of operation, together with additional objects and advantages thereof will best be un- 5 disposed adjacent thereto. and '5 feed intoa plurality of independent ampliderstood from the following description of a specific embodiment, when read in connection with the accompanying drawings, in which:

Figure 1 is a schematic drawing showing a recording system constructed according to my invention;

Fig. 2 is a diagrammatic view showing the essential elements of the averaging device in its relation to a record amplifier and the recording galvanometer;

Fig. 3 is a schematic view showing areproducing system provided according to my invention;

Fig. 4 is a schematicview showing a photosensitive device particularly adapted to be utilized with apparatus constructed in accordance with my invention and the input elements for the amplifiers cooperating therewith; and

Figs. 5, 6, 7-and 8 are modifications of photosensitive devices that may be utilized in the practice of my invention.

The apparatus shown in Figs. 1 and 2 comprises a stage 1 having a plurality of microphones 3 and The microphones 3 fiers 7 and 9, and the output terminals 11 and 13 of the amplifiers are connected in parallel to .a coil 15 whereby the position of the movable element 1? of a galvanometer 19 is predetermined.

The position of the movable element 17 of the galvanometer I9 is microscopically responsive to the energy transmitted to the exciting coil 15 from the amplifiers [and 9. By reason of its instantaneous variations in position, a light beam from a suitable source 21, which is suitably modified by an optical system '23,.is deflected to produce an impression of variable width on a film strip 25 on which it impinges.

The above describedrecording process is well known in the art. However, according to my invention, the line of zero current-modulation of .thesound track 2'? on the film 25 is shifted in accordance with the position of the object fron which the sound to be recorded is emanating.

The energy delivered by a predetermined element of the amplifiers 7 and 9 is fed into an averaging device 29. The averaging device has an output responsive to the influence of one of the amplifiers 7 and "9 in which the translated electrical energy predominates and feeds into the exciting coil 31 of a second galvan'ometer 33. The

a function of the disposition of the elements 210- Y wally-emitting the sound.

Although the system of recording illustrated herein is of the variable-area type, a record of the variable-density type may be produced in accordance with my invention in a manner which is apparent. In such a case, an optical valve,

such as a Kerr cell, for example, is d sposed be-- light valve of the glow-lamp type may be utilized, in which case, the source is so disposed'relative' to the microscopically-responsive mirror 35 that the light therefrom is suitably deflected before it impinges on the film.

1 Finally, it should be noted that, whi1e,'in' the illustrated embodiment of my invention, two galvanometers are utilized, my invention may equally as well be practised with a single galvanometer that is biased in response to the directional effect of the sound and that responds to the instantaneous variations introduced by reason of the character of the sound in its biased positions.

In Fig. 2, a portionof one of the amplifiers 7- and 9, together with the averaging device 29, is shown in detail.

Each of the microphones 3 and 5 is connected in the grid circuit of an amplifier tube 37,in the plate circuitof which the primary windings 39 and 41 of a plurality of transformers 43 and 45 are connected. The secondary winding 47 of one transformer 43 is connected to the input'of the next stage of amplification of the system, while the secondary 49 of the other transformer 45 is connected to the terminals of a ballast lamp 51 that comprises one arm of abalanced circuit, such as a Wheatstone bridge. A balanced lamp 53, fed, ina similar manner, from the first stage of amplification of the other amplifier 9, is connected in a conjugate armof the bridge and. the coil 31, whereby the mirror 35, responsive to the microscopic condition of the sound, is actuated, being connected between two conjugate terminals 55 and 57 of the bridge.

The bridge is adjusted by a plurality of variable resistors 59 and 61 in such manner that zero current is transmitted throughthe exciting coil 31 of the microscopic galvanometer 33 when the sound energy impinging on one of the microphones 3 and 5 is substantially equal to that on the other. As the sound impinging on the microphones varies, the resistance of the ballast lamps 51 and 53. corresponding to the microphones, varies, and, if the system becomes unbalanced,'current is transmitted to the coil 31 of'thegalvanometer 33. The reflector 35 associated therewith is then deflected in such manner that the recordinglight beam impinges on the film 25 in a region'corresponding to the relative magnitude of the predominating sound emitted and to the disposition of the sound emitters' c It will be apparent to those skilled in the-art that the ballast lamps .51 and53 may be replaced by resistors of other types that respond with facility 'to' variations in current transmitted through them. Forexample, grid-controlled ther mionic tubes may be utilized in lieu of the lamps 51' and 53. In such case, the plate circuits of the tubes constitute the arms of the bridge, while the grid currents of the tubes are fed, from the amplifiers 7 and 9.

In Fig. 3, a reproducing system is shown schematically. The system comprises a light source 63, a condensing lens 67, wherebythe radiations from the source 63 are gathered and focused on a slot 69, and a lens system 71 whereby the slot 69 is imaged on the film 25 in the form of an attenuated rectangle, .73 extending across the film 25. i

A photo-sensitive device 75, comprising an elongated container 77 having disposed therein, a plurality of independent cathodes 79 and anodes 81, is located behind the film 25. The light transmitted through the film 25 and modified by the "the same character.

their disposition in the photo-sensitivedevice, and

their state of'excitation is dependent on the lateral orientation of the sound track on the film.

The current produced between each cathode 79 and its corresponding anode 81 is fed into a plurality of independent amplifiers 83, 85 and 87, which, in turn, feed into a plurality of loud speakers 89, 91 and 93, The loud speakers 89, 91 and 93 are arranged in the vicinity of thepicture screen (not shown) in a manner corresponding to the microphones 3 and ,5 in the recording setting, and it is seen thatlthe magnitude of the sound reproduced by the loud speakers willbe dependenton the state of excitation of the individual cathodes 79 and, therefore, on the original disposition of the sound-emitting bodies in the recording setting.

.It is well to keepin mind that theloud speakers may be disposed behind thescreen or adjacent to the screen, in a manner dictated byexpe'rience in installation. Moreover, the amplifiers 83,85 and 87 and the speakers 89, 91 and 93-need not be of V In certain reproducing equipment, I have found that the central ampli fier 85 and its corresponding speaker 91 should preferably be capable of delivering more volume per unit'input than the other'repi oducing merribers. By reason ofsuch an arrangementythe amplification applied to the amplifiers transmitted to the terminal speakers: 39 and 93may be so limited that they do not become overloaded even if the original sound on one side of the stage "lis comparatively loud.

In Fig. 4, a photo-sensitive device 95 of a type having a common cathode 97, a plurality of principal anodes 99 and a plurality of auxiliary anodes 101 is shown. The cathode 97 and the principal anodes 99 are respectively connected to the terminals'of a plurality of inductors 103 which are" the input elements to a plurality of amplifiers.

It is apparent that the anode associated with the region of the cathode wherein the radiant energy'is localized will receive a greater charge than the anodesassociated with the other regions of the cathode. Moreover, it is a Well known fact that photo-electrons are emitted from the surface, in general, in a direction perpendicular to-the surface. Consequently, if the cathode surface comprises a plurality of cylindrical arcs 105 and the anodes 99 are disposed at the centers of curvature of the arcs, the result produced by radiant energy of a localized character will correspond with comparative accuracy to the localization of type illustrated in Fig. 4 is particularly adapted to be utilized in apparatus of a type wherein the loud speakers in the central region of the repro ducting stage are, capable of delivering more power output than the speakers in the terminal regions of thestage. a i

In Fig. 5, a photo-sensitive device '107 having a plurality of individual cathodes 109 and a plu- :rality of principal and auxiliary anodes 111 and ,1l3associated with each cathode is shown. The purpose ofrthe auxiliary anodes-113 in the photosensitive device 107 of the type illustrated in Fig. .5 is thesame as the purpose of the corresponding anodes 101.,in the-device 95 of the type illustrated in Fig. 4.-

-, In-Fig. 6, a photor-sensitive device 115, comprising a single cathode 117 having plural-arc configuration and a single anode 119 associated with-each arc, is shown.

In =Fig.'7, a photo-sensitived-evice 121, of a type having ;a plane cathode 123 and a plurality of associated anodes 125, is illustrated.

In Fig. 8,,a photoesensitive device 12'7, incorporating a*cathode v121 of the type having the configuration oi an are made up of a plurality of reentrant smaller arcs 131 is shown. A plurality -of' anodes-133 are associated with the smaller arcs 131.

Withthe exception of the photo-sensitive de- .vices that may be-utilized with my improved reproducing system, a single embodiment of my invention has been illustrated herein. The system has 'been shown, in general, schematically, and the improvements that are ordinarily incorporat- =ed=in photo-acoustic and recording, reproducing systems are not shown. It is understood, howeven thatapparatus incorporating these im provementsare equivalents which lie within the scope of my invention. In particular, it is set forth that a record constructed according to my invention may incorporate; the ground-ncise-reducing features which are beginningto be utilized inthe motion-picture art. .Again, it should be noted that, while modifications, of photo-cells having independent anodes and a common cath- :odeare illustrated and described hereinabove, my invention maybe equally as well practiced with photo-cells having a common anode and aplurality of independent cathodes.

- Finally, it should also be added that a sound record utilized in the practice of my invention should preferably be of the negative type. That is to say, the record should be of the type wherein; the sound track region is transparent while the remaining region is opaque. By utilizing such a record, difliculties from ground noise are eliminated. For purposes of clarity, a positive record is shown in Fig. 3.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereoi are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

'1. Directional photographic acoustic-recording apparatus comprising a plurality of devices for translating acoustic energy intoelectrical energy, said devices to be distributed in the region where the sound is to be produced, means for averaging the electrical energy produced in each translating device todisplace the beam in accordancewith :the source of sound, a medium for receiving impressions of said translated electrical energyand aneans for localizing said impressions on said me dium in accordance with the magnitude of the average energy produced from each of said trans-' lating devices.

2. Directional acoustic-recording apparatus "comprising a pluralityof devices for translating acoustic energy into electrical energy, said devices to be distributed in the region where the sound is to be reproduced in such-manner that the magnitude of the electrical energy delivered byeach of said translating devices for a given sound is dependent ,on the .relative position of .the emitter of said sound,a medium for receiving disposition of the source of said acoustic energy,

and means for producing a permanent physical impression of said electrical'energy, the last said means varying the location -of said physical impression responsive to the directional-effect produced in said translating means. a

4. In apparatus for recording sound, means for producing an attenuated beam of radiant energy,

condition of the sound to be recorded, and means for laterally displacing said beam in accordance with the relative position of;.the source of said sound, the magnitude of said lateral displacement being dependent on the distance of said source from a predetermined point.

5. In a system for recording sound in combination a balancednetworn having in each -of a plurality of arms thereof a idevicecapable of responding to the average value of the electrical energy suppliedthereto, the output of'said network being responsive. to the relative conditions ofsaid energy-responsive devices in each of the arms thereof, means for independently supplying electrical energyto each of saidenergy-responsive devices, means for projecting a light beam andmeans, to be actuated by the-output of said network, for deflecting said light .beam in accordance with the relative condition of each of said energy-responsive devices. v

6. In combinationa plurality of devices for converting acoustic energy into electrical energy, a balanced network having, in each of a plurality of arms thereof, a device capable of responding to the average magnitude of the electrical energy supplied thereto, the output of said network being responsive to the relative conditions of said energy-responsive devicesin each of the arms thereof, means for coupling one of said energyconverting devices to each of said energy-responsive devices, means for projecting a beam of radiant energy and means, to be actuatedby the output of said network, for deflecting said beam of radiant energy in accordance with the relative conditions of. said energy-responsive devices.

said translating devices relative to that of the' others varies in accordance with the variation of the lateral position of said record on said film strip.

8. In combination a film strip carrying a sound record,.said recordbeing laterally displaced .on

said beam being responsive to the instantaneous acoustic energy of any of said translating devices relative to that of the others varies in accordance with the variation of the lateral position of said record on said film strip.

9. Apparatus for reproducing sound comprising a plurality of devices for translating electrical energy into acoustic energy, a medium having permanently impressed thereon a single record carrying'the combined impression of the sound to be reproduced and of a predetermined space distribution of said sound in the region of reproduction'and means, to be energized in accordance with the impressions of said record on said medium, for supplying electrical energy to said translating devices whereby a sound is produced having a-quality and a distribution corresponding to said record.

10. In combination a film strip carrying a sound record, said record being laterally displaced on said film strip and the magnitude of said lateral displacement being varied in a predetermined manner, means for converting said record on said film strip into electrical energy variations, said means including a photo-sensitivedevice having a single cathode and a plurality of anodes to cooperate with said cathode and optical means for so projecting the impression on said film strip on said photo-sensitive device that the current in said device flows between said cathode and one of said anodes selected in accordance with the lateral position of said impression on said film strip, a plurality of devices for translating electrical energy into acoustic energy and means for supplying said electrical energy variations to said energy-translating devices in such manner that the response of said translating devices varies in accordance with the variation of the lateral position of saidimpression on said film strip.

11. In combination a film strip carrying a con- 7 tinuous sound record, said record being laterally displaced on said film strip and the magnitude of said lateral displacement being varied in a predetermined manner, means for converting the record on said film strip into electrical energy variations, said means including a photo-sensitive device incorporating a plurality of pairs of elements, each element comprising a cathode and anode, in a single container, and optical means for so projecting the record'on said film strip on said photo-sensitive device that the current in said device at any time flows between one of said pairs of elements selected in accordance with the lateral position of said impression on said film strip, a plurality of devicesfior translating electrical energy into acoustic energy and means for supplying said electrical energy variations to said energy translating devices in such manner that the output acoustic energy of any of said translating devices varies relative to that of the others in accordance with the variation of the lateral position of said record on said film strip.

12. Apparatus for reproducing sound comprising a plurality of devices for translating electrical energy into acoustic energy, a photo-sensitive .device that is capable of selectively responding in accordance with the localized efiect of radiant energy impinging thereon, a medium having impressed thereon a single record of sound, said record being localized in said medium in a man ner corresponding to a predetermined distribution of said sound in the reproducing medium, means for energizing said photo-sensitive device in accordance with said record and means for energizing said translating devices in accordance with the output of said photo-sensitive device.

WM. MAURICE PATTERSON.

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