US962081A - Apparatus for recording sounds. - Google Patents

Description

T. A. EDISON. APPARATUS POR RECORDING SOUNDS,

APPLICATION FILED Nov.'13,'1903.

. Patented June 21, 1910.

2 SHEETS-SHEET l.

Attorney T. A. EDISON. APPARATUS fon RECORDING SOUNDS.

APPLICATION FILED NOV. 13, 1903.

Patented June 21.1910.

2 SHEETS-SHEET 2.

GNN

A tmmevv Witnesses resentative as may iunririi)y STATES PATENT OFFICE.

NEW JERSEY.

, THOMAS A. EDISON, OP LLEWELLYN PARK, ORANGE, NEW JERSEY;l AssIeNon To NEw JERSEY PATENT COMPANY, Or ORANGE, NEW JERSEY, A CORPORATION Oia- APPARATUS POE RECORDING SOUNDS.

Speeication of Letters Patent. o Patented J nn 21, 1910.

ApplhiatioliVK filed November 13, 1903. Serial No. 180,998.1

To all whmri t may concern:

Be it known that I, THOMAS ALVA EDISON of Llewellyn Park, Orange, in the county of Essex and State of New Jersey, have invented certain-Improvements in Apparatus for Recordingr Sounds,- of which the followingisa description.`

My invention relates to limprovements in a paratus-for recording sounds, particularly oithat'type in which phonographic records'. are formed, and which records are of varyingl depth, but the invention ma be employed in connectionV with recor s o f the amo hone type, which are of uniform pth ut of irregular conformation The .object of this invention is to produce a recording mechanism capable of recording sound waves phoiioriaphically, as truly replbe of the original waves and their quality, eliminating excessive and false amplitudes of vibration, without any consequent loss in volume of the sound produced.

The invention consists in the production of a phonographic device whereby sound waves throughout the range of music may be recorded and reproduced truly, false amplitudes of vibration of the recording mechanism being eliminated, aiid the recording and reproduction of both grave fundamental notes and overtones rendered possible.

The invention further consists in the various details of construction for the improvenient of phonographic recorders generally, as more fully set forth hereafter in the specifcation and the appended'claims.

At the present time those skilled in the art' have beenunable to record and reproduce music having all the tones within the range of music suiciently like the original to obtain aA record: that is salable ycommercially; this is especially'true of music of the piano, and, notwithstanding many millions of honograph records have been made andsol records formed of iano music alone are not sold and are not ound in any catalogue of the manufacturers. With recording instruments existing before this invention, it is impossible to produce a satisfactoi-'y piano record. If-.it is attempted to record the overtones which give music its pleasing qualities, the instrument must be made very sensitive, as the waves which form overtones are manyv times weaker than the f undamentals. If the recorder is made suhciently sensitive to so record'these overtones, the powerful fundamental tones of the bass :ict soviolently upon the recorder as to throw the recording knife out of the recording material in the case of cylindrical records and give excessive amplitudes in the case of fiat records. If the recorder is made so insensitive as to prevent this latter action no overtones are recorded and the quality is lost. \Vliile at' the present time manufacturers of cylindrical records use the piano as an accompaniment, the deep bass notes are never used, but only those inthe higher register; in addition the vibrating'part of the iecorder itself is sympathetic to the graver tones and serves only to intensify these serious defects. I have by exhaust-ive experimentation discovered that the true sound waves over the whole range ofmusic from theinost grave to the highest pitched tone do not actually have the amplitudes which are implied by the throwing of the recording knife out of contact with the record surface and the vibrating periods of the recorder itself need not necessarily be 4graveythat this is due to defective mechanism con@ structed upon a wrong principle and that if certain changes are made in the mechanism so that it will operate upon a different principle, it may be adjusted with sutlicient sensitiveness to record the necessary overtones and the most powerful bass notes of a piano and permit the reproduction of the original tone with almost perfect qualityand with a greater volume than has hitherto been thought possible. I have traced down and ascertained by experiment that the cause of the excessive and false amplitudes of vibration is due to the elasticity of the recording mechanism itself and by eliminating theV principal part of this elasticity, the true amplitudes due;y to the sound waves do not cause the recording knife to be thrown from the recording surface when the recorder is rendered suiliciently sensitive and that the grave tones of the diaphragm may be changed to a higher rate and O such a small amplitude as not to distort therecord.

The Ordinary recording mechanism now in general use oonsists of a circular diaphragm generally of glass about 1&1,- inches inl connected to a lever secured to the waves and the elastic rubber which isl strained by the flexing of the disk. For the purposes of illustration let 'such a disk be cut in sections like the spokesiof a wheel, there will be a numberof vibrating reeds each elastic and flexing by itself as well as flexing by distortion of its rubber support, and sympathetically resonant to some tone in the lower register of the iano, harp or similar instrument. Indepen ent of the fact of its having a tone or vibrating period, it has a mass and possesses weight and if movl by a force applied at the end of such a section a large amount of the power applied must be lused in distorting the rubber clamp in addition to that use for exing the section, and this mass under the action of the stored power in the rubber tends to make several movements when only a single impulse was given to its end thus it cannot ossibly follow the sound waves of music. f anumber of impulses are appliedvto the end which im ulses have the same period of vibration as the section itself, the amplitude due to the first few waves will be less than the following waves, althou h the original sound waves may all have t e same amplitude, hence there can be no true record of a ltone the same as that of the sector, and this is true of the whole diaphragm.which is formed of a large number ofvsections, so to s ak. It is impossible to make the rubber c amps of uniform elasticity, hence there will e man parts or sections of the diahragm wi different vibrating eriods. lven in the case of waves havin v1 rating periods unlike the diaphragm, t eir action on the diaphragm causes energy to be stored up in the elastic clamp, and the action of this stored energyon the mass of the dia- -iexing the ver elastic g ass woul increase the vo ume of sound, and permit of hragm tends to force it to make more virations than there are sound waves producing interference and false amplitu corresponding to the sound wavesand a lar e proportion of the ener contained in eac sound wave is lost as gevat in deforming th'e yrubber (which extends around the' periphery of a circle about 3% inches in circum erence), which ener if applied to greatly the recording of the exceedin ly weak overtones. I may mention that t e heat. lost by iioats :liquid material. The diaphragm is secured lat its center to one end of a reed which is es not` distorting rubber is very much greater than by distorting glass, as the latter is a substance of great elasticit and minimum internal friction, while rubber is just the contrary. The recorder in general use is also defective by reason of certain other causes which coperate to produce distortion of the dia hragm. First, the diaphragm is placed un er strain by the pressurewhich is necessary to force the redording knife into the record material. only with the material but with different degrees of hardness occurring upon different parts of the surface of the record material.

econd, the record itself cannot be made to' run absolutely true. These two causes work in conjunction to ,produce an ever varyin lexure of the diaphragm, independent o the action of the sound waves', and thiscontinuous iie`xure of itself distorts the record roduced by. the sound waves. Third, the

act that, the fundamental tone of the diaphragm and its elastic support is grave and of great amplitude, and constantly varies as the tone is prolonged, produces additional distortion.

In the recorder of my invention, a very `wide departure in construction is made. The

diaphragm is not secured at theedges but 1n a mass of viscous liquid, or semisupported at its other end by an elastic connection from the chamber, and has the recording knife fastened at its end about the center of the diaphragm. When assembled the diaphragm and knife are afloat so to speak, and are sustained entirely by the supported end of the reed. The viscosity of t e semi-liquid material around the edges is such that when the recorder is adjusted so the knife tracks the record material to the proper depth, the diaphragm will have no stress upon it. It is in its `most sensitive condition, and if the record cvlinder is eccentric or a part ofthe record harder than another part,the viscous liquid olers scarcely any resistance to a motion of translation to such slow movements but on the other hand acts Anearly as a rigid body to movementsl of great uency similar to sound waves. The ,edge of the diaphragm makes scarcely vany movement and yet is free of all strain whereas ifzthe record is untrue the edge of the diaphragml may make movements several times greater than those produced by the sound waves. Thus no matter what variation in the hardness of the material or what reasonable amount of eccentric motion of the record takesv place, the dia permits of a rise `and fal of barometric pressure which permits sound waves, and

phragmvis unstressed and in its most sensitive con- .'dition. The viscous semi-liquid material acts' to close the ychamber completely and thus 'I5A v This pressure varies not lio lus

I' taken on the seapaiA being non-elastic no energy is stored upto distort the sound Waves, and the amount'of energy abstracted is less than if the diaphragm were between rings of rubber or other elastic material, and such energy is not returnable to the mechanism as motion to produce distortion. In addition', this want of elasticity 'changes the fundamental note of the diaphra' i and` environment from a. grave iiote oglliigh amplitude to a very inucli liiglieriiote and of a greatly reduced amplitude combined effect of vthe sound waveand the diaphragm in tune with it is entirely insuiii- .cient to throw the knife from the record or disturb in an appreciable amountthe quality of the recorder sound. The viscosity of the material used around the edges is such that itsl surface tension prevents it from flowing to any extent at ordinary temperature at slight gravity gradients, hence the recording a paratus if kept level will be serviceable fbr semi-Huid material .is .quickly and easily renewed.

Iii order that the invention may be better understood, attention is directedto the'accompanying drawings, forming a part of this specification, and in which Figure 1 is a bottom view of the recorder; Fig. 2 is a sectional view thereof line 2-2 of Fig. 1; Fig. 3 is a sectional view taken on the -line 3-3 of Fig. 2; Fig. 4 is a front view of the body; and Fig. 5 is an enlarged sectional view of the body, diaphragm and recording knife.

In `all of the above views corresponding parts are represented by the same numerals of reference. y

The liollowed tube 1, which is connected to, or is a continuation of the vusual horn or funnel, is carried by the usual support (not shown) and has ears 2-2 between which is pivoted the head or barrel 3. To tli'e latter is secured the sound box or body 4 to the lowerA face of which'is connected f the glass or mica diaphragm 5. Across the lower face of the body and below thev diaphragrn is the tracking lever 6, which serves as a support for 'theball 7, which latter rests upon the record kcylinder and supports the body, allowing it to oscillate about the pivot between the ears 2 2 and accominodate itself to all large irregularities in the surface of the blank. i

The `ball 7 is of a comparatively little curvature, but sufficient to permit of universal adjustment, Aand is preferably made of a jewel, of which sapphire seems to be the best material, as it does not have any appreciable chemical effect-upon the record blaiik;. furthermore it is susceptible of taking a high polish, so that its passage over the record will not scratch or otherwise injure it.

so much reduced that thev several days and then the viscous` body 4 by means of a screw 8, which passes through a. slot 9 formed within an elastic extension 10 of the lever which forms an elasticl connection,'so that the lever, too'ether extremity of the lever engages with anl adjusting screw 11, passing through a threaded opening in an extension 12 on the body, and

the ball 7 and the body may be adjusted whenthe machine is running.

The knife 13 is attached to the diaphragm adjacentl to its center and onthe saine luie magnesium on account of lightness.y The 4foot 14 issecured to the diaphra by a suitable cement, such as melted lshel ac.

The diaphragm is connected at its-periphery to the bottom of the chamber or body by means of a mass of viscous or semiliquid material 15,50 that it 'will be entirely supported agiainst gravit yand the thrust of the cutting nife solely by the elastic reed 1,6, the material 15 forming a' seal to close the joint between the edges ofthe diaphra in and the chamber. The reedis preferaly made of white pine or similar light wood and is of a varying vertical section, deeper than it is wide and is secured to the foot 14 by a cement, referabl melted shellac.

The end of) the ree at 17 is made much thinner, so that it will vibrate, easily and the sions, toward t e fixed extremity, the` configuration of the entire reed bei such that it will be practically unsympat etic with any note of great amplitude, and on account of the varying vertical section will give no harmonics that would tend to disturb the record. The end 17 of the reed is secured the body 4. l n

The stiffness of the reed at 17 should be suficient, so that the act of tracking the kniferin'the record will not cause the edlge of the diaphrgm to be forced lagainst t e edge `of the b y 4, .but onl moved in the viscous'liquid. The knife ilustrated is of yusual form. The reed 16 'forms a continuathrust caused by the action of the record upon the knife. When the reed is arranged at an angle to the thrust/caused by the action of the record on the knife, the knife has a i tendency tor chatter which injuriously affects the record. v

The mass of viscous or semi-fluid material 15 does not serve to support the diaphragm f' against gravity, but serves as a moving point or points about which the dia hragm vibrates. It is necessary to keep t equantity of viscous material in use in the manner The 'lever 6 is connected to one-end of the with the ball 7 may be adjusted in relation to the center of the diaphragm. The other,

by means of which 'the relative position of to a pillar 18 formed upon a continuation` of of travelas the ball 7, by means of a su port or foot 14 which is formed preferab y of j reed increases radually in vertical dimention of the knife,and is in the direct line of shown, down to the smallest guantit mit of its surface tension being s cient; to

hold it u in position, and not flow to any tension and fgreat viscosity, it is not chan ed encircling flan conditions.`

- `ticall continuous with the upper surface by action o the atmosphere and altoget er is a peculiar substance and well adapted for the purpose. It'can be produced of varying degrees of viscosity by a proper manipula,- tion of the heat and thus give a range for varyin conditions. The space between the inner e' ge of the diaphragm and thebody 4 will usually be .020 of an inch and between the of the diaphragm and the inside 19 about .010 of an inch and below the ower edge and the iiange 19 shoul project a suicient distance to hold the viscous material. These dimensions can be varied to meet varying The form of recorder which I nave devised and which is illustrated in Figs. 1 and 2 also has some advantages over that in common use, as the chamberfor producing the nal pressures upon the diaphragm is small and of a roper pro rtion and is so arranged in ation to t e receiving nel or horn that the sound waves do not suf.-

fer either partial or total deflection at anyl int and aty the same time the wall friction is reduced. This is acco f lished by forming the head or barrel 3 o the same width practically throughout (see Fig.` 1 and not taperin it as it aterally enters t e body 4 as has Vtherto been the practice. The telp o t e o -within the headv 3 a proac as they nil'ntlhge diaphragm, but tbl; sides do not. The top 20 of the head forms a line prac- 22 o the inside of the body 4, which upper surface inclines from a with the connection of the ead, to the other edge of the diaphragm at 23; and there are no angles or obstructions inthe th of the sound waves. B connect' e head 3 with ythe sideof e body 4, A e air passage way 'is straight, consequently the `sound waves do not suer any deiiection and by the use of the proper funnel angle the power of the sound waves to act upon the ,diaphragm is greatly increased.

A small weight 24 is preferabl remove ably carried on the head 4,'and w ichmay be changed or varied to suit the conditions of .work, or character of sound required.

The center of gravity ofthe weight shouldr t0 per:

mit of the adjustment of tracking of the diaphragm oeaos'i ordinari] be directly over the center of the trackin all 7. v

` By a justing the position of the ball 7 upon therecord by means of the screw 11, the whole recorder canv rapidly and easily be made to approach and recede from the face of the recording material and thus perof the recording knife to the required depth into the record material after the machine is started. In theactof forcing the knife into the record material, the reed 16 is flexed at its point of fastening 17. If the reduced section ofthe reed at 17 is made stiff the reed as a whole will be very little flexed and there will be but a slight movement of the edge of the diaphragm in the viscous semi-liquid material, and uring the act of flexing of the reed, the diaphragm will also be exed due to the retardation of its movement through theY viscous li uid, but when the knife :is once tracked a stress on the diaphragm is removed.` To rapid movements, ike sound waves, the resistance to motion is powerful and the diaphragm has little, if any, to'and fro movementl at its edges, the recording bein due almost entirely to flexing of the'diap ragm. l

If the part 17 of the reed is made very thin, the reed will be fiexed to a eater extent and the movement of the diap agm in the viscous liquid will be eater, but in no case will the edge of t e diaphragm touch the metallic parts, but will always be and immersed in the li uid. A movement `of more than .02 o an inch will seldom be required and the proportions illustrated should be suiiicient to permitv of movements of this amount. The thickness of th reed at 17 is easily changed, and serves to adjust the sensitiveness of the whole vibrating portion of the recorder and the ener stored up in the elasticity of that portion of the reed at 17 is quite small as comared to that of a diaphragm clamped in rub rs -atits edges, hence the movements of the vibrating apparatusdue to its own elasticity or capacity to returnthe stored up energy is very small and negli 'ble and thereforevthe full effect of the con ensatioiis and rarecations ofthe sound waves comes into full playwithout the disturbance produced by elastic mechanism4 of the recorder mechanism as now used. v

It is obvious that the principle of operation can be varied in many ways and that it can be employed for recording on machines of the disk forni, to prevent the making of a record of excessive amplitudes, produced' by the conjunction of the sound waves and elastic recording mechanism and which the reroducin needle does not and cannot folow, but Jumps across, and also to recordthe sound more perfectl tones and increase e volume of sound..

, to strengthen the over- While I have described my improvements as being particularly designed for .use in a aparatus of the phonograph type, it will bev I which flow more or lessj'readily, some of which are sometimes termed semi-liquid materials, the consistency of the material being only determined by ,the qualification that it must be -characterized by great internal friction or viscosity.

y Having now described my invention, what I claim as new and-desire to secure by Letters Patent, is as follows:

1. In a device for recordingsound waves, a. vibratory plateory disk connected to a frame by a permanently liquid material which is characterized by reat internal friction or viscosity, substantially as set forth.

2. vIn a device for recording sound waves, a vibratory plate or disk connected to a frame by burnt rubber, substantially as set forth.

3. In a device yforfrecording sound Waves, a vibi-atory plate or disk, the edges of which are connected to a frame by a permanently liquid material which is characterized by great internal friction or viscosity, substan- Y liquid material characterized by great intiallyy as set forth. 4 t

4. In a device for recording sound waves, a vibratory plate or disk supported at or near its center and connected to a frame by a permanently liquid material which is characterized by great internal friction or visy cosityfsubstantiallyas set forth.

5. In a device for recording sound waves, a vibratory plate or disk supported at or near its center and connected to a yframe by burnt rubber, substantially as set forth.

6. In a device for recording sound Waves, the combination of a vrecord surface, a diaphragm and stylus capable of moving as a phragm and at its other end t'o a whole toward and away from said surface and a reed connected` atone end to the diaphragm and at its other end to a support and operating. to support they diaphragm and. by1 flexure to permit movements of the diap ragm, substantially as set forth.

7. In a device for recording sound Waves, the combination of a record surface, a diaphragm and stylus capable of moving as a whole toward and away ,from said sur ce, `a reed connected at or near one end to the diasupport and operating to support the diaphra m and by iexure to permit movements of tie diara said reed extending longitudinally ih line with the thrust of the record sur-'p` face upon 'the recording stylus, substantially y as set forth. I

8. In a. device for recording sound waves, the combination of asound ox havingan opening, a diaphragm occupying a position. 4 within said opening and a seal between said diaphragm and opening composed of ay permanently liquid material .characterized Vby great internal friction or viscosity, substantially as set forth. r

9. In a device for recordin soundl waves, the combination of a sound ox' having an opening, a 4diaphragm occupying a position within said opening and a seal between said dia hragm and opening com osed of burnt rub er, substantial 1y as setl orth.

10. In a devicefoiirecording sound waves, the combination of a sound boxfhaving an opening, a diaphra ni Within said opening, a support connected to said diaphragm at or near its center and a seal between said diaphragm'and' opening composed of a permanently l'liquid material having great internal friction or viscosity, substantially as Aset forth.

11. In a device for recording sound waves, the combination of a sound box having an opening, a diaphragm within said opening, a supportjconnected to said diaphragm at or near its center and a seal between said diaphragm vand opening composed of burnt rubber, substantially as set forth.

12. In a device for` recording sound waves, f

the combination of a vibratory diaphragm connected to a frame by a permanently ternal friction or viscosity, and a reed connected at one end to the diaphragm and at its other end to a support, and operating by flexure to ermit movements of the diaphragm, su stantially as setyforth.

'13. In a device for recording sound waves, the combination of a vibratory diaphragm connected at or near its edges to a frame by a permanently liquid material, characterized byV great internal friction or viscosity, and

connected at or near its center to a vibratory support, substantially as set forth.

14. In a device for recordingsoundv Waves, the combination of a vibratory diaphragm connected at or near its edges to a frame y burnt rubber, and connected at or near its center to a vibratory support, substantially as set forth.

16. In a device for recording sound waves,'

whole toward and away .tlexure to the combinatlon of a record surface, a diaphragn'i and stylus capable of moving as a from said surface, and a wooden reed connected at one'end to the diaphragm and at the other end to a support and operating to support the diaphragm and by fiexure to permit movement of the diaphragm and stylus, substantially as set forth.

17. Inga device for recording sound waves, the combination of a record surface, a diaphragm and stylus capable of moving as a whole toward and away from said surface, and a reed connected at one end to the diaphragm and having its other end of reduced section and connected to a sup ort, said reed operating to support the diap ragm and by llexnre to permit moif'ement o -the dia'- phragni and stylus, substantially as set forth. 1S. In a device for recording sound waves, the combination of a record surface, a diaphragm, a stylus moving toward and away from said surface and a reed of tapered vertical section connected to said dia hragm, and having its other end of reduce section and connected to a support and operating by ermit movements 'of the diaphragm andpstylim,l the largest vertical section of the reed being adjacent the reduced portion, substantially as set forth. 1 l

19. In a devicelfor recording sound waves, the combination `of a sound box havingv an opening closed by a dia hragm and a second opening for receiving t e sound waves, said latter opening being substantially equal in width to the diaphragm opening, substantially as set forth.

20. In a device for recordin sound waves, the combination of a sound ox having an opening closed by a dia hragm and a second opening for receiving t e sound waves, said latter opening being substantially equal in width to the diaphragm opening and situ- [sean] ingbeing substantially equal in opening to a point adjacent the far ed ated at one side thereof, substantially as l forth.

21. In a device forrecordin the combination of a sound opening closed by a diaphra and a second opening communicating wi a ssage for conveylng the sound waves, said atter openwidth to the diaphragm o eningfand situated at one side thereof, and t e lateral walls of the said passage being arallel, substantially asset forth.

22. In a evice for recording sound waves,

sound waves, `x having an a sound box having an opening in which the diaphragm is situated, a wall opposite said opening, anda second openin at one side of the diaphragm opening, sai walls slopi uniformly from a point adjacent the secoii` o the diaphragm, substantially as set for 23. In a device for recordln sound waves, the combination of a sound opening in which the diaphragm is situated and a sound conveyin tube opening into the side of saidkbox e upper and lower walls of said tube an sound box converging as they approach the diaphragm, substantially as set forth'.

24. In a device for 'recordi the combination of a soundl opening in which the dia and a sound conveying tu opening into the side of said box, the upper and lower walls of said tube and sound box converging as they approach the diaphragm and the top of the sound box being ractically a continuation of the u per wail of the tube, substantially as set fbrth. v

x having an hragm -is situated ox having an 70 sound waves,

'lis

This specification sigiedand witnessed this 11th day yof Novem r 1903. y

THOMAS A. EDISON. Witnesses: f

LEONARD A. Dran, JN0. Roar. Tanon.

'n n hereby Certified ,that in Letters Patent No. 962,081, grand'June 21,1910,` upon the application of Thomas A. Edison, of Llewellyn Park, Grange, New Jersey, foran improvement in Apparatus for Recording Sounds, errors appear in the y printed specification requiringcorreetion, as follows: Page 4, line '42, the word laterally should be stricken out and inserted after the word fit,"samealine, first. occurrence, and same page, line 116 the word raretcations should read 'm1-efectivas; and that the said 'Letters Patent should be read with these corrections therein that the same may conform to the record of thecase inthe Patent Oce.

signed und sealed his 20th day of september, A. n., 1910.

C. C. BILLINGS, Acting Commissioner of Patente.

whole toward and away .tlexure to the combinatlon of a record surface, a diaphragn'i and stylus capable of moving as a from said surface, and a wooden reed connected at one'end to the diaphragm and at the other end to a support and operating to support the diaphragm and by fiexure to permit movement of the diaphragm and stylus, substantially as set forth.

17. Inga device for recording sound waves, the combination of a record surface, a diaphragm and stylus capable of moving as a whole toward and away from said surface, and a reed connected at one end to the diaphragm and having its other end of reduced section and connected to a sup ort, said reed operating to support the diap ragm and by llexnre to permit moif'ement o -the dia'- phragni and stylus, substantially as set forth. 1S. In a device for recording sound waves, the combination of a record surface, a diaphragm, a stylus moving toward and away from said surface and a reed of tapered vertical section connected to said dia hra and having its other end of reduce section and connected to a support and operating by ermit movements 'of the diaphragm andpstylim,l the largest vertical section of the reed being adjacent the reduced portion, substantially as set forth. 1 l

19. In a devicelfor recording sound waves, the combination `of a sound box havingv an opening closed by a dia hragm and a second opening for receiving t e sound waves, said latter opening being substantially equal in width to the diaphragm opening, substantially as set forth.

20. In a device for recordin sound waves, the combination of a sound ox having an opening closed by a dia hragm and a second opening for receiving t e sound waves, said latter opening being substantially equal in width to the diaphragm opening and situ- [sean] ingbeing substantially equal in opening to a point adjacent the far ed ated at one side thereof, substantially as l forth.

21. In a device forrecordin the combination of a sound opening closed by a diaphra and a second opening communicating wi a ssage for conveylng the sound waves, said atter openwidth to the diaphragm o eningfand situated at one side thereof, and t e lateral walls of the said passage being arallel, substantially asset forth.

22. In a evice for recording sound waves,

sound waves, `x having an a sound box having an opening in which the diaphragm is situated, a wall opposite said opening, anda second openin at one side of the diaphragm opening, sai walls slopi uniformly from a point adjacent the secoii` o the diaphragm, substantially as set for 23. In a device for recordln sound waves, the combination of a sound opening in which the diaphragm is situated and a sound conveyin tube opening into the side of saidkbox e upper and lower walls of said tube an sound box converging as they approach the diaphragm, substantially as set forth'.

24. In a device for 'recordi the combination of a soundl opening in which the dia and a sound conveying tu opening into the side of said box, the upper and lower walls of said tube and sound box converging as they approach the diaphragm and the top of the sound box being ractically a continuation of the u per wail of the tube, substantially as set fbrth. r v

This specification si edand witnessed this 11th day yof N ovemiir 1903. y

- THOMAS A. EDISON. Witnesses: f

LEONARD A. Dran, JN0. Roar. Tanon.

x having an hragm -is situated 'n n hereby Certified ,that in Letters Patent No. 962,081, grand'June 21,1910,` upon the application of Thomas A. Edison, of Llewellyn Park, Grange, New Jersey, foran improvement in Apparatus for Recording Sounds, errors appear in the y printed specification requiringcorreetion, as follows: Page 4, line '42, the word laterally should be stricken out and inserted after the word fit,"samealine, first. occurrence, and same page, line 116 the word raretcations should read 'm1-efectivas; and that the said 'Letters Patent should be read with these corrections therein that the same may conform to the record of thecase inthe Patent Oce.

signed und sealed his 20th day of september, A. n., 1910.

C. C. BILLINGS, Acting Commissioner of Patente.

ox having an sound waves,

'lis

Corrections in Letters Patent No. 962,081.

lt is hereby certified that in Letters Patent No. 962,081, granted June 21, 1910,

upon the application of Thomas A. Edison, of Llewellyn Park, Orange, New Jersey, l for nn improvement in Apparatus for Recording Sounds, errors appear vin the l printed speeicntion requiring correction, as follows: Page 4, line 42, the word ,i laterally should be stricken out and inserted after the word Mit,V

i 5 first occurrence, and same page, line 116 the word rarecations should read same line,

rmwfac/z'nns; and that the said 'Letters Patent should be read with these oorretions i therein that the same may conform to the record of the casein the Patent Oiee.

Signed und sealed this 20th day of September, A. D., 1910.

C. C. BILLINGS,

Acting Gommssomr QfPafenta.

[SEAL] l

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