US1411235A - Sound-reproducing machine - Google Patents

Description

C. L. CHISHOLM, DECD. A. w. CHISHOLM, EXECUTRIX. SOUND REPRODUCING MACHINE. APPLICATION FILED OCT. 18. m5. RENEWED NOV. 15,1919.

1,41 1 ,235. Patented Mar. 28, 1922.

INVENTOR,

W1TNESSES- r 46' Ol a ML U mzm/ Alfameyfi.

C. L. CHISHOLM, DECD. A. w. CHISHOLM, EXECUTRIX. SOUND REPRQDUCING MACHINE APPLICATION FILED OCT. 18,1915. RENEWED NOV. I5, 1919.

' 1,411,235. I Patented Mar.28,1922.

W1 TNESSES:

omfreo STATES PATENT ,ro Fi-cE.

CHARLES L. cnrsnomu, on NEW GLASGOW, nova SCOTIA, CANADA; Amen 'w. cnrs- HOLM, EXECUTRIX OF THE WILL OF SAID CHARLES LOGAN CHISHOLM, DECEASED,

ASSIGNOR TO THE CHISHOLM DEVELOPMENT GQ, INCL, OF BOSTON, MASSACHU- SETTS, A CORPORATION OF MASSACHUSETTS.

sounn-nnrnonucmo.MACHINE.-

Specification of Letters Patent. f Patented Mar. 28, 1922.

Application filed October is; 1915, Serial m. 56,570. Renewed member s, 1919. Serial in. 338,324.

To all whom it may concern;

Be it known that" IQGHARLES L. CHRIs- HOLM, a subject of theKing of England, residing at New Glasgow, 'Province'of Nova Scotia, Dominion of Canada, have invented 'a new and useful Sound-Reproducing Macluded. in such reproduced sounds, so that the sounds obtained-from the sound record have a naturalne'ss not heretofore attained.

It is known that sound records contain overtones to which sound-reproducing devices as heretofore constructed are not sensitive, so that the reproduced sounds have a difierent quality from the original soundssound.

71d there is a noticeable difference between the reproduced sounds and the originals of the recorded sounds. The result is that a sound-reproducing machine in operation is readily recognized as such and is not mistaken for the original of the recorded sounds, wherefore the reproduction has .a sound-reproducing machine uality of its own, because of the absence oi over tones in such reproduced sounds, although theovertones-are actually recorded in the sound record.

While the present invention is not directed to the recording of sounds, the perfection of the reproduction is dependent in part upon the perfection of the recording of the sounds. Such perfection in recording is due to a large extent to having the diaphra m of the recording sound box superficially ree with the stylus arm in contact with the center of th 'diaphragm over. an area of ute extent approaching as near as practicable to a" geometric point. For the best results such arfn should also be free from ac-' tual attachment to the diaphragm. Good results may be obtained even when a minute quantity of wax 'or the like is used to connect the sides of the pointed end of the stylus to the central portionof the diaphragm, with, however, thejextremity of the point in actual unattached contact with thediaphragm. I I

-In the present state of'theiartsound records have the sound record grooves of sinuous form or or varying depth. The sinuous form is known as a gramophon'e record and .i

the form of varying depth is known as a phonograph record. These different kinds of,sound records require stylusses' and stylus carrying means of different shapes and constructions for actuating the reproducing elements, which latter usually include a diaphragm for converting the variations of the" sound record grooves into air Waves simulating the original sound. The original sound" record, the reproducing diaphragm, the stylus, and the means for transmitting the motions of the stylus to the diaphragm all have an influence upon the reproduced It is due'to the customary manner of-.connecting the stylus to the diaphragm for causing vibrationof the latter that there is loss of the over-tones and thecha'racter' of the reproduced sound is correspondingly modified, and the reproduced sounds therefore have a talking machine character to a greateror less extent.

It has been found that b transmitting the v vibrations of the stylus o the diaphragm through the intermediary of electrical means after the manner of a telephone, many of the-'over-tones heretofore lost are impressed upon the reproducing diaphragm and the reproduced sound has the natural-ness ofthe original "sound, so that the reproduced sounds very .closely simulate the original sounds to an extent noticeably superior to the commercial sound reproducing machines, with the advantage that such naturalness of reproduction fromcommercial types of I sound records is commercially feasible.

The present invention contemplates the employment of a microphonic element, or,

if need be,. more than one microphonic element, located practically at or in some other relation to the stylus, while the vibrations imparted to the microphone by-the stylus are transmitted to the diaphragm through Figure '8 is a section lengthwise oflthe.

' stylus arm and microphonic element utillzed electromagnetic means similar to the action of a telephone receiver.

It is best to employ a microphonic element of minute size to avoid material interference with the vibration of the stylus, and, furthermore such microphonic element should be free to move with or under the action of the stylus, so asto avoid material dampening of the vibrations, and for this reason the microphone may be of an inertia type, whereby the variations of contact are brought about by an inertia action, as will hereinafter appear.

The present inventionalso contemplatesthe combining of the mechanical transmissionof the vibrations from the stylus to the diaphragm with electrical transmission thereof, whereby the tones due to the mechanical transmission have superposed thereon over-tones due to the electrical transmission, so that loudness of reproduction with naturalness of reproduction is obtainable.

The invention contemplates numerous dea tail improvements which'will appear here inafter. v n

The invention will be best understood from aconsideration of the following detailed description, taken in connection with the ac companying drawings forming part of this specification, with the further understanding that while the drawings show a practical' form of the invention, the latter is not confined to any strict conformity with the showing of the drawings, but may be changed and modified, so long as such changes and modifications come within the scope of the appended claims. 1

In the drawings Figure 1 is an elevation of a sound box equipped for electrical transmission to the diaphragm of the impulses imparted to the stylus by the sound record.

Figure 2 is a section on the line 22 of Figure 1 with some parts in elevation, and also showing electrical connections diagrammatically.

Figure-3 is a view similar to Figure 1 but illustratinga sound box equipped with both v mechanical and electrical transmission of vi brations from the stylus to the diaphragm.

Figure 4 is a section on the line 4-4 of Figure 3 with some parts in elevation. Figure 5 is an end elevation of the diaphragm actuating magnet and stylus arm of Figures 3 and 4, the diaphragm being shown in section.

Figure 6 is a erspective view of the'upper end of a' cabinet type of sound reproducing machine showing the invention applied.

Figure 7 is a view similar to Figure 2 lowing a somewhat modified form of the invention with'the electrical circuits in diaas a'holding screw for the stylus in accordance with the showing of Figure 1, the drawing being on a considerably magn fied scale.

Figure 9 is a side elevation of a microphonic element with parts broken away to show some of the internal construction, the scale being also considerably magnified.

Referring to the drawings there is shown a sound box casing 1 carryin a diaphragm 2 and provided with thejusua neck 3 at the back of the casing for the attachment of the sound box to the swinging arm element 4 of the sound amplifier of the instrument. So far as the sound box and its support, to-

gether with a sound amplifier, are concerned, such parts may follow the usual .practice of'well known commercial machines,

and while in the drawings the types of sound boxes shown are those adapted for.

the gramophone type of sound record, it will be understood that by well understood changes in construction the phonograph type of sound record and sound box may be utilized. The characteristics of the different types of commercial sound reproducing machines are so well known that it is not deemed necessary to illustrate the phonograph type, since the invention will be fully understood from the forms shown in the drawings. v

In Figure 1 a rock arm 5 is mounted upon the sound box by means of trunnions 6 and bearing screws 7 constituting the well known pointed bearing employed in many delicate instruments.

The screws 7 extend through lugs 8 on the sound box 1, after the customary manner, so that the arm 5 may have an extent of rocking movement about the axis of the trunnions 6. The arm 5 at the end remote from the sound box, since-such arm projects be yond the periphery of the sound box, is'

formed into an elongated socket 9 designed to receive a reproducing stylus 10 which in the drawings is shown as of the customary steel needle type, although, of course, the fiber type of stylus may be used or the; jewel type or any other form of stylus employed in sound reproducing machines. In the case of the employment of the needle type of stylus, it is necessary to frequently renew the stylus, wherefore the Styluses are made readily removable from the stylus arm and are ordinarily held in the socket 9 by a set or clamp screw easily operable by hand. In the structure'shown in Figure 1 there is a microphonic element 11 employed as, the clamp screw for the stylus, such inicrophonic element being shown on a greatlyfl'enlarged scale in Figure 8. The micropht'inic element is provided with a casing 12 containing aback contact 13 and-a frontcontact in the, form of a diaphragm 14 carried by the casing and used as a conductor, as will hereinafter ap-v cover may engage.

defining betweenthe diaphragm and the back contact a granule chamber containing a.

to the casing in any suitable manner, as, for

instance, by a spun-over edge 17 of the cas-' ing. Since it is convenient to employ the cover 16 as an electric conductor, insulation 18 is introduced betwenthe edge of the cover and the casing, althou h, ofcourse, it will be understood that since it is not obligatory to use the cover'asan electric conductor the insulation may in such case be omitted. The cover 16 in the particular showing of Figure 8 is connected to the back contact 13 by an insulated conductor 19 soldered or otherwise joined to a projection 20 on the back contact, such projection being, of course, suitably insulated from the casing. Secured to the' diaphragm 14 is a stem 21 having a threaded portion adapted to screw into the :socket end 9 of the stylus arm 5 in order to clamp the stylus 10 in readily removable relation to the socket. The stem 21 is extended through a passage 22 in the cover 16, so that electrical connection between the stem 21 and cover 16 is prevented.

Since the diaphragm 14 is utilized as one terminal of the microphonic element the stem, 21 being fast to the diaphragm and being made of metal is utilized as a conductor electrically connecting the diaphragm with the stylus arm 5 and the latter may also be pear. The utilization of the cover 16 as one terminal of the microphone and'the use of the microphone as a binding screwfor the stylus necessitates a. contact with which the Such a contact is shown in Figures 2 and 8 as an elastic member 23, which may be in the form of a strip of metal bent upon itself with one end fast 'to but electrically insulated from the stylus arm 5 and the other so situated that when the microphonic element is screwed so that the stem 21 clamps the stylus 1.0 the strip 23 is in engagement with the cover 16 preferably under some elastic pressure, thusinsuring good contact." A conductor 24 is made fast at one end to the stri 23 and is included in a circuit to be described. The stylus arm 5 ismaintained in a central or neutral position b an equalizer spring 25 whichmay be ma e fast to the sound box casing 1 and extend to opposite sides of the axis of rocking of the armbso that the arm is central.-

ized or equalized by the spring, but will readily rock under impulses imparted to the stylus 10 by the sound record groove.

The microphonic element is supported solely by the stem 21, which in turn is carried by the stylus arm. Therefore, when the stylus is vibrated by the sound record roove such vibration is imparted to the diap ragm 14 and because of the inertia of-the microphone the ra-nules are subjected to compression and released therefrom in a manner similar to the action of a microphonic I element when the casing is held rigidly and the diaphragm is vibrated.

However, by mounting the microphonic element upon the stylus arm close to the stylus, that is, between the support for the stylus arm and the record engagin end of the stylus, the microphone-is sub ected to violent agitation without undue dampening effect upon the stylus, although. the stylus arm constitutes the sole support for the microphonic element through the connectin stem in turn connected to the diaphragmv o the microphone.

The microphonic element may be made a minute since excellent results are obtained when the microphonic casing is one-half to five-eighths of an inch in diameter and about threesixteenths of an inch thick. While the actual weight of the microphonic element is small it is so constructed that it has suflicient inertia to cause relative movements of the microphone diaphragm with 95 respect to the body of the microphone to cause the desired action of the microphone.

It is because the microphone is mounted to act in the manner described that it'is termed an inertia microphone, thereb distinguish- 10o ing it from microphones in w ich the body of the microphone is ri idly secured to a support or mounting. he inertia microhone has the advantage of producing far ess dampenin effect upon the stylus than a microphone ot erwise mounted and the beneficial effects obtained by the microphone far outweigh any detrimental effects due to the mountin of the microphone upon the stylus arm, this being especially true when the microphone is mounted between the support for the stylus arm and the active and of the stylus. f

Extending across thesoundbok casing 1 I is a bridge piece 26 to which is secured an electromagnet 27 having a )ole piece 28 in close relation to the face of the diaphragm 2 at the center portion of the latter. ,The microphone and electromagnet are suitably electricall joined so that electrical undulathe vibrations of the stylus are mechanicall imparted to the sound box dlaphr m an furthermore, the reproduced soun s have been found to be superior in naturalness to electrically operated reproducing diaphragms where the microphones have been so situated as to have a material dampening effect upon the vibrations imparted to the stylus by the sound record groove. The superior results obtained are believed to be due to the employment of the inertia microphone and to the mounting of the microphone so as to receive the impulses of the magnet 27 has one side connected directly to metal parts of the sound boat as by a conductor 29 connected to the brldge plece 26,

. while the other side of the magnet27 is con- ,nected by a conductor 30 'to .a batter 31 which may be taken as representative 0 any suitable source of current. The battery 31 I. ,is shown'as connected by a conductor 32, in-

eluding aswitch 33, to one side of a rheostat '34, while the other side of therheostat is connected by a conductor 35 to a switch 36 having in the path of its arm the terminals of two conductors 37, 38. The conductor 37 is connectedto a volt meter or othersuitable indicating instrument 39, the other side of which is connected to the conductor 24.

The conductor 38 is bridged, about the instrument' 39 so that the atter .may be included in or cut out of circuit without affecting the continuity'of the circuit.

Considering the switch 36 as coupled to the conductor 38 with the rheostat 34 adjusted to the zero point and the switch 33 closed, the circuit may be traced from the battery 31, through switches 33 and 36, conductor 38, conductor 24, spring member 23, cover 16, conductor 19, back contact 13,- granules 1 diaphragm 14, stem 21, "stylus arm 5, sound box 1, bridge piece 26, conductor 29, winding of the electromagnet 27 and conductor .30, back to the battery 31. Such an arrangementi'w'hen in operation causes the production of a variable current in the electric circuit and a corres onding variation in the'magnetic effect of t e electromagnet 27 especially if the pole piece 28 be a per-ma nent magnet. Under the conditions assumed the microphone and electromagnet are sub jected to the full power of thebattery 31 as modified 1) the microp one. In order that an operator of the sound reproducing machine may pro- -duce modifications in the reproduction of the sound, the rheostat 34 is provided,

whereby extra resistance is introduced into the variations by resistance in' the circuit and the effect of the battery is correspondingly reduced, so that. the repro: duced sound may be materially modified and softened. p

Since an electric battery will be the usual source of electric current, such battery is liable to weakening by use, and, therefore, an electric measuring instrument 39, shown as a volt meter. but which may be any other type of electric measuring instrument, is provided so that an operator may ascertaim at any time the'conditionof the battery and if the reproduced-sound is not of the char-- acter expected the operator may quickly ascertain whether the fault is in a weakening of the battery. The volt meter need be used but momentarily, since the switch 36 provides for the'cutting in and out of the volt meter, at will.

In Figure 6 there is shown a cabinet 40 containing a sound reproducing machine which may be considered as provided with a sound box 1 having a diaphragmv 2, a microphone. 11 and an electromagnet 27. The cabinet is shown as provided with the usual cover 41 and with aturntable 42 carrying a record tablet 43. In such a cabinet there is room for placing the battery 31 of which a storage battery willbe found to be a convenient form. The rheostat 34 is con- 'venientl'y mounted within the cabinet in accessible position and the volt meter 39 is also conveniently mounted within the cabinet in accessible position for observation.

The structure of Figures 1 and 2 ma be included in a cabinet form of mac ine shown inFigure 6 or in any other type of sound reproducing machine, and the same is true of other forms of the invention to be described.

In Figure 3 those parts similar to the structure of Figure 1 are designated by the same reference numerals. The principal difference between the structures of Figures 1 and 3 is that in the structure of Figure 3 means for the mechanical transmission of the stylus vibrations to the diaphragm 2 are included, so as to operate in conjunction with the means for the electrical transmission. The stylus arm5 is replaced by a stylus arm 5 which may have the same kind of mounting as the stylus arm 5 and the corresponding parts are designated by the same reference numerals as in Figure 1. The stylus arm 5, however. has a continuatlon 44 continued to the center of the diaphragm and there provided with a bent terminal 45 having a pointed extremity 46 hearing against the central portion of the diaphragm. The point 46 approaches as closely to a geometric point as is feasible, since theoretically the geometric point is the ideal form. Experience has shown that a broad contact and relatively rigid attachment of the stylus arm with the central portion of the diaphragm is materially detrimental to the attainment of the best results and a reduction of such contact as well as the elimination of fixed connection between the stylus arm and the diaphragm is conducive to far superior results. It is for this reason that the pointed end of the stylus arm Where engaging the reproducing diaphragm is made of as small area as practicable and junction means are avoided. For the best effects in the mechanical transmission of the vibrations to the diaphragm the extremity of the pointed ends of the stylus arm should be in actual contact with the diaphragm without the interposition of any wax or the like and the point where contacting with the diaphragm should be of the smallest practicable area.

In the structure of Figures 3 and 4 .a spring 25 is used to constrain the pointed end 46 of the stylus arm toward the diaphragm to maintain the stylus arm at all.

times in contact with the diaphragm. To show that it is not necessary to employ the microphonic element as a binding screw'for P the stylus, the microphonic element 11 in the structure of Figures 3 and 4 is attached to the stylus carrying end of the arm 5 close to the'stylus, the attachment being by a stem 21* which may be of considerably smaller diameter than the stem 21 of-Figures 2 and 8, although any particular size is not obligatory. In the structureof Figures 3 and 4 a thumb screw 47 such as is customarily used, is applied to the socket end 9 of the stylus arm to hold the stlyus 1O place and the microphone 21 is mounted on the socket end 9 of the side of the latter remote from the thumb'screw '47. Since it is desirable that the impulses imparted to the diaphragm be applied thereto as close as possible to the center of the diaphragm the electromagnet 27 has a split'pole piece 28 straddling the bent end 45 ofthe stylus arm 44. Otherwise the structure may be similar to that of Figure l.

Since in the structures described the diaphragm 2 is actuated by an electromagnet,

such diaphragm is either made Wholly of iron or has an iron armature Where under the influence of the electromagnet. For acoustical reasons it is preferred to have the diaphragm 2 wholly of iron and such diaphragm may follow telephone practice. The electrical connections of the structures of Figures 3 and 4 may be the same as that of Figures 1 and 2 or may be such asis hereinafter described with reference to Figure 7. The microphone 11 of Figures 3 and 4 is shown in Figure 9. where the stem 21 is indicated as of smaller diameter than the stem 21, but otherwise the microphonic element may be the same as that of Figures 1 and 2, except for the omission of the contact member 23, which is not necessary in the structure of Figures 3 and 4.

a stylus socket 9 adapted to receive a stylus I 10, the socket having a thumb screw 47 similar to the thumb screw 47 of Figures 3 and 4. The stylus arm hasan extension 44 on the side of its support remote from the stylus and such stylus arm extension 44 may reach toabout the center of the diaphragm, although it is neither'connected to nor touches the diaphragm. A centralizing spring 25 similar to the centralizing spring 25 of Figures-1 and 2 may be employed to hold the stylus arm in a normally neutral position. At the end of the arm 44 opposite the central portion of the diaphragm the arm carries a microphonic element 11 by a stem 21 attached to the diahragm of the microphonic element-similarly to the showing of Figure 9. The microphonic element therefore operates as an inertia microphone in the manner already described, wherein a diaphragm or vibratile member acts directly upon the resistance element being assisted in its action under vibratile impulses imparted to the stylus, by the inertia of the microphonic structure. It will be understood that while the vibratile element of the microphone has been described as a diaphragm, other forms of vibratile elements'or contacts may be used, although the diaphragm is to be preferred. Like the microphone elements shown in the other embodiments of the invention, the microphonic element 11 of Figure ,7 is wholly supported by the stem 21 attachedto the end 44 of the stylus arm remote from the -.stylus. Since the microphone element is located about opposite the center of the diaphragm and relatively close thereto, sulfi- .eient room does not remain for the electrotype may be used in any of the structures,

the horseshoe type havin the advantage of greater attractive strengt In the showing of Figure 7 a somewhat different arrangement of the electric circuits is provided. The conductor 24 leading from one side of the microphone 11 is connected to one end of the primary winding 48 of an inductioncoil 49, the other end of the primary winding being connected by a battery 31, which in turn is connected to a rheostat 34, and the latter is connected by a switch arm 36 to either one of two conductors 37, 38 of which the conductor 37 is connected to an indicating instrument 39 and the circuit is then continued by a conductor 50 to some metallic part of the sound box. The electromagnet 27 is connected on one side to thesound box and on the other side by a conductor 30 to one end of the secondary Winding 51 of the induction coil 49, the other side of thisflwinding being connected to the conductor 50 all in the manner common to telephone installations.

"way the microphone 11 sets up an alter nating current in the electromagnet 27 similarly to the current set up in an ordinar' telephone receiver.

It will be understood that the electrical installation of Figure 7 may be followed in the'structures of Figures 1 to 4, or in any other embodiment of the invention. I

The particular type of sound box is not material to the present invention, nor is the particular type of sound record, andhence no attempt has been made in the drawings to show the various types of sound boxes'or sound records, all of which are well known. Some of the principal features of the present invention include the minute microphonic element, the arrangement of the microphonic element with relation to the reproducing stylus and the mounting of the microphonic element so that it has'the least amount of dampening effect upon the reproducing stylus and the inertia of the body of the microphonic element is utilized, and the combination of mechanical and electrical transmission to the stylus vibrations from y the record to the sound reproducing diaphragm.

The invention is applicable, to sound re producing machines of. all sizes and designs,

whether of the disk or cylinder type or of.

the gramophone or phonographic type.

While the microphonicelement has been described as an inertia microphone of the granular type and also as provided with a diaphragm with a stem by which the mi crophonic element is wholly'supported, it is to be understood that the invention is not necessarily confined to such particular type or construction of microphone, especially with respect to some of the features of the invention.- It is possible to obtain good results with microphonic elements of other thanthe granular type, or with a kind not provided with a diaphragm or with a kind otherwise supported than by a stem-or with a kind where the inertia characteristic is due to other means than the body of the device.

In this means for the sound-box diaphragm upon the sound-box, for it may be otherwise mounted so long as it maintains the proper ergy employed may be varied at will, so that v the resultant effect in audible sound is that of crescendo and diminuendo inany shade of strength within the capacity of the instrument. By properly constructing the rheostat 34a so that its changes are gradual, either continuously or by small steps in waves well understood by electrical engineers,'the gradations in the reproduced sounds may be sensibly continuous throughout the range of the rheostat. In the draw-.

ings the showin of the rheostat is merely conventional an it is to be understood that any type of rheostat suitable for the purposes of the present invention may be employed.

-In some types of sound reproducing machines gradation in the reproduced sounds i accomplished b the employment of varieties of styluses. In other sound reproducing machines the styluses are not changeable, and in such cases it has been proposed to produce gradations of the reproduced sound by damper or'other, mechanical structures.

With the present invention the gradation is performed as gradually as desired, and without in any manner interfering with the free course of the air waves from the sound, box to the external air.

The rheostatic control has the advantage of changing the power of the reproduced sounds at will to any extent throughout the range of adjustment and with any type of sound reproducing instrument without requiring any change in the sound reproducing elements. The rheostatic control has the further advantage in that it may be operated at the sound reproducing instrument or at any point outside of or distant therefrom, and the effects of changes in the rheostatare instantaneously apparent in the reproduced sound.

What is claimed is 1. Means for the reproduction of recorded sounds, comprising a sound reproducing dia phragm, electro-magnetic means for actuating it, a stylus arm with a stylus receiving portion, and a microphonic element electrically connected to the electromagnetic means and provided with a support constituting a clamping means for holding a stylus in the stylus arm. 1

2. Means for the reproduction of recorded sounds comprising a sound reproducing diaphragm, electromagnetic means for actuat ing the diaphragm, a;stylus arm with a portion adapted to receive a reproducing stylus, and a microphonic element electri-' aphragm, electromagnetic means for actuating the diaphragm, a stylus arm with a portion adapted to receive a reproducing stylus, and a microphonic element electrically connected to the electromagnetic means and having a threaded stem entering the stylus arm to clamp the stylus thereto, said stem constituting the sole support for the microphonic element, whereby the inertia of the microphonic element is utilized in the production of the microphonic effect.

4. Means for the reproduction of recorded sounds comprising a sound reproducing diaphragm, a stylus carrier having a portion adapted to temporarily receive a reproducing stylus, electromagnetic means-1n opera-i tive relation to the diaphragm for vibrating it, and a microphonic element electrically connected to the electromagnetic means and provided with a screw constituting the clamp screw for the reproducing stylus and also the sole support forthe microphonic element.

5. A sound box for sound reproducing machines provided with a sound reproduclng diaphragm, electromagnetic means for actuating the diaphragm, a rockable stylus arm mounted on the sound box with one end of the stylus arm adapted to receive a reproducing stylus, and a microphomc element for controlling the electromagnetic means and mounted on and supported solely by the rockable arm: between the axis of rocking of the arm and that end of the arm adapted to receive the reproducingfstylus.

6. Means for the reproduction of recorded sounds comprising a sound box having a sound reproducing diaphragm, electromagnetic means mounted to be in actuating relation to the diaphragm, a rockable arm mounted on the sound box, yieldable constraining means in operative relaton to the stylus arm for maintaining it in a neutral position, and a microphonic element mounted on the stylus arm and electrically connected to the electromagnetic means.

7. Means for the reproduction of recorded sounds comprising a sound box having a sound reproducing diaphragm, electromagnetic means in actuating relation to the dia-' phragm, a rockable stylus arm carried by the sound box, and an inertamicrophonic element connected to and controlling the electromagnetic means and carried solely by the stylus arm.

8. Means for the reproductionof recorded sounds comprising a sound box having a sound reproducing diaphragm, a stylus arm in operative relation to the diaphragm to mechanically yibrate it, and elect ically operated means for vibrating the diaphragm in operative relation to the stylus arm to cause the diaphragm to respond to the combined action of the mechanical and electrical means under impulses imparted thereby by the stylus.

. 9. Means for the reproduction of recorded sounds, comprising a sound box having'a sound reproducing diaphragm, a stylus arm mounted on the sound box in operative relaton to the diaphragm to mechanlcally vibrate it, electromagnetic means movable with sound box in operative relation to the diaphragm to electromagnetically vibrate it, and a microphonic element mounted on the stylus arm for vibration thereby, and electrically connected to the electromagnetic means, whereby both the mechanical and electrical impulses produced by the vibration of the stylus are caused to simultaneously act upon the diaphragm to vibrate it.

10. Means for the reproduction of recorded sounds comprising asound box with a sound reproducing diaphragm, a stylus-arm mounted on the sound box in operative relation to the diaphragm to mechanically vibrate it,- electromagnetic means mounted on the sound box in operative relation to the diaphragm to vibrate it, and a microphonic element mounted on the stylus arm adjacent to the stylus end thereof and electrically connected to the electromagnetic means, whereby the vibrations'of the stylus are both mechanically and electrically imparted simultaneously to the diaphragm.

11. Means for the reproduction of recorded sounds, comprising a sound box having a sound reproducing diaphragm, a stylus arm carried by the sound box in operative relation to the diaphragm for mechanically vibrating it in accordance with the vibrations imparted to the stylus by the sound record, electromagnetic means inoperative relation to the diaphragm for vibrating it, and an ined sounds comprising a sound box having a.

sound reproducing diaphragm, a vibratile stylus arm carried by the sound box in operative relation to the diaphragm for mechanically Vibrating it in accordance with the vibrations imparted to the stylus by the-sound record, electromagnetic means in operative relation to the diaphragm for vibrating it, and an inertia microphonic element electrically connected to-the electromagnetic means for controlling said means and supported solely by the stylus arm, the microphonio element being mounted on the stylus arm between its axis of vibration and the stylus end of the stylus arm.

comprising arm mounted on the sound box, and a microphomc element for controlling the electromagnetic means and mounted on and sup ported by the rockable arm between the axis of rocking of the arm andthe stylus carrying part thereof.

In testimony that I claim the foregoing as my own, I have hereto afiixed my signature in the presence of two Witnesses.

CHARLES L. CHISHOL-M.

\Vitnesses:

JOHN H. 'SIGeERs, EDITH L. BROWN.

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