US1455942A - Phonograph sound box - Google Patents

Description

Patented May 22,

WILLIAM Ii'f. VENAELE, OF PITTSBURGH, YENNSYLVANIA.

PEONOGBAPH SOUND 13031.

Application filed August 17, 1821.

To all whom it may concern:

Be it known that 1, WILLIAM lilnro VEN- ABLE; a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania,have invented certain new and useful Improvements in Phonograph Sound Boxes, of which the following is a specification.

This invention relates to sound boxes for the reproduction of recorded sounds from records which carry the sounds in the form of undulatory or waving lines adapted to be traced by a suitable stylus or needle. This is the almost universally accepted type of record at the present day and my invention, as stated, relates to improvements in sound boxes for use in connection with such records.

The principal object of this invention is to improve the quality of the reproduced sounds. This is accomplished by a structure which wi l be described hereinafter by means of which it is possible to regulate the tone and the volume of the reproduced sound and to eliminate objectionable qualities commonly introduced by present methods of reproduction, although not existent at the time of recording. I accomplish the foregoing by means of a novel construction which employs some improved parts corresponding to old parts now in common use as well as certain new parts designed to perform new functions not hitherto reco 'nized in this art. a

More specifically and yet briefly enumerated the objects of my invention may be said to consist in the provision of improved means for insulating the sound box from the tone arm; the provision of improved means for mounting the diaphragu'i; the provision of an improved fulcrum for the vibration lever as well as an improved mounting for said fulcrum; the provision of suitable means for supplementing the elasticity of the diaphragm; the provision of means for regulating the degree of vihration of the vibration lever; and the provision of means for regulating the degree of motion of the diaphragm with respect to the degree of motion of the vibration lever.

These together with such other objects as may hereinafter appear or are incident to my invention I obtain by means of a construction which is illustrated in preferred Serial No. 493,010.

form in the accompanying drawings, wherein Fig. 1 is a section through my improved sound box taken on the line 1--l of Fig. 2; Fig. 2 is a front elevation or face view of the sound box; F ig. 3 is. a section on the line 33 of Fig. 2 except for the omission of certain cushioning parts between the sound box and the tone arm; 4: is a plan view of the'underside of the sound box; Fig. 5 is a sectional view corresponding to that of F ig. 3 illustrating a somewhat modified arrangement; Fig. 6 is a sectional view similar to that of 1, but illustrating a modified form taken on the line 6 6 of F ig. 7 Fig. 7 is a face view partially in section taken as indicated by the line 7 in Fig. 6; Fig. 8 is a section on the line 88 of Fig. 7 Fig. 9 is a section similar to those of Figs. 3, 5 and 8, but with certain parts omitted such for instance as the diaphragm and the vibration lever, illustrating a further modification; and Fig. 10 is a par tial sectional View illustrating a detail of the assembly. 7

Referring to the drawings the diaphragm 1 is carried within the sound box casing 2 by means of an improved mounting which consists of a stri of rubber or other suitable yielding materiall and a filler strip surrounding the strip 3 and both of which are arranged to enter the groove 5 in the casing 1'2. The casing has cylindrical flange or rim 6 and the strip 3 is adapted to be held under compression between this flange 6 and the inner shoulder T of the groove 5when the tiller member l isforced in between the flange and the rubber. in assembling these parts I make use of a spacing cord 8 (see Fig. 10) beween the diaphragm and the casing, but this cord may be removed after the strip 3 is in place as it serves no useful function except to space the diaphragm properly during assembly. The rubber strip alone supports the diaphragm in position with reference to the casing and it will be noted that it engages the edge of the diaphragmv .lt makes an air tiglit'joint but not one which exerts much pressure upon the diaphragm and one which will permitthe diaphragm to relieve itself of all strain should it, for any reason, become warped or cramped during the process of mounting or other cause. Ordinary use will cause its edge to work upon the rubber until such strain is relieved. This self-adjustment of the diaphragm is impossible with the ordinary method of mounting which consists in clamping the diaphragm between rubber washers or rings. The filler strip 4: represents aconvenient and somewhat preferred means for pressing the rub ber against the edge-of the diaphragm, but any other suitable means might be employed and while rubber is the most suitable material known to me at present for this purpose, other materials having similar physical characteristics might be employed.-

The casing is provided with a tubular e);- tension 9, preferably coaxial with the diaphragm, between which and the tone arm or other suitable member for carrying the sound box, not shown in the drawings as it forms no part of this invention, are located an inner metallic sleeve on attaching member and a coiled rubber tube 11, the tube being pressed into the space between. the sleeve 10 and the tubular portion 9. A. washer 12 of'rubber or other suitable vibration absorbing; material prevents contact between the inner end of the sleeve 10 and the casing 2. Similar cushionsfor the purpose of preventing sound vibrations from being communicated by the casing: to the solid parts ofv the tone arm, have been known in the art, but to this function, however, I add that of allowing a relatively free motion of the casing itself fo" purposes which will be set forth hereinafter. My improved cushioning moans permits a much more free motion than is possible with the usual solid cushion.

Thevibration lever 13, sometimes called a stylus bar, and the stylus holder let are provided with an im roved fulcrum comprising a relatively heavy or massive yoke 15, soldered or otherwise secured to the thin circular band or collar 16, and the supporting or fulcrum wires proper 17. One end of the yoke is deeply "slotted as at 18, forming}; a tongue 19'which yields slightly when the wires 18 are slightly bent in order to pre vent stretching of the wires. The wires are preferably composed of steel music .wire carefully selected as to size and mounted between the tongue 19 at one end of the yoke and the solid portion at the other end of the yoke. Emln'acing the wires so as to grip them securely is the matrix 20 which is preferably an integral part of prefer to assemble vibration lever 13. The collar 16 is clamped around the flange 6 of the casing 1 with the rubber strip 21 between to act as a cushion. For clamping purposes the band is provided with wings and a screw and nut 23 and 24, as most clearly shown in Fig. 2. The purpose of the band or collar 16 is to provide a convenient means of securing the yoke to the casino; with a cushion therebetween, Other means might be used and the cushion might be of some other shape than that which is here shown, but this particular construction is very convenient to assemble inasmuch as it requires but a single screw.

The means for connecting; the stylus in the stylus holder with the diaphragm will now be described and while the preferred arrangement is illustrated in Figs. 1 to 4 inclusive, reference will first be made to Figures 5 to 9 inclusive as illustrating a somewhat simpler construction, but one which involves the invention just as much as do Figs. 1 to 1 inclusive Referring particularly to Figs. Ste 8 inclusive, 25 is a projection or lug on one side of the casing rim or flange 6, and 26 is a bracket on the opposite side. A length of music wire 27 is secured between the lug 25 and the bracket 26 and extends across the face of the casing in substantial pa "allel'ism with the diaphragm. The thumb screw .48 is threaded through the bracket 26, passes freely through the collar 16, and the insulating strip 21. and bears against the flange or rim 6. By means of the thumb screw the tension of the wire 27 may be regulated or varied at will.

The end of the vibration lever 18 is insorted into the slot29 in the matrix provided for it and into which it fits without binding and the end of the lever is then soldered or otherwise firmly secureo to the wire 2". In the construction of Figs. 5 to S inclusivethis wire does not pass directly over the center of the diaphragm, but the lever 13 has a projection 30 which extends over the center of the diaphragm and to this projection is soldered-or otherwise secured the wire strut 31 which passes through a hole in the center of the diaphragm. I

hen this step has been reached, the diaphragm and the fulcrum wires both be ingr still in their neutral or unstrained condition, the vibration lever 18 is cemented or soldered to the matrix preferably by means of a resinous wax and the strut 31 is cemented to the diaphragm. The wire 27 may then be made tenser or less tense by adjuslinr the thumb screw 28 without imposing any strains upon diaphragm or fulcrum wires. The strut 81 is thin and relatively flexible and will therefore, be capeb e of transmitting; to the diaphragm only vibrations which are substantially per;

liil) pendicular to the surface thereof, and the lever 13 being firmly secured to the wire 27 cannot be readily displaced by a sufficient distance to damage the diaphragm or to produce edgewise strains therein.

It is not essential that the wire 27 be supported in the exact manner shown in Figs. 5 to 8 inclusive and in Fig. 9 I have shown what might be termed an alternate construction wherein it is secured to the brackets 26 and 26 which in turn are secured to the band 16 instead of to the flange or rim 6. In this figure I have also shown a somewhat modified thumbscrew 28 which is long enough to reach across the face of the casing from the bracket 26 to the bracket 26 I do not wish to limit myself to the particular arrangement for the support of the wire 27 or for its adjustment.

Nith the arrangements just described, or similar ones, it is obvious that the wire offers resistance to forces tending to vibrate the lever at the end where it communicates vibrations to the diaphragm. Its effect may be likened to that of making the diaphragm itself stiffer, or more difficult to bend. The tighter the wire, the more resistance it offers. Thus when the wire is relatively tight, a greater resistance is offered to the lever at the diaphragm end and consequently greater forces will be exerted to displace the fulcrum than when the wire is relatively loose. These forces result in some displacement of the relatively heavy or massive yoke 15 with reference to the casing, and of the casing with reference to the support therefor, such as the tone arm, and both of these members are cushioned upon their supports to permit such movement within appropriate limits. These relatively heavy bodies, however, are more easily affected by vibrations of small frequency (low pitch) than by those of large frequency (high pitch). Tightening the wire therefore reduces the volume of low pitch sounds emitted by the diaphragm to a greater extent than it reduces the volume of high pitch sounds. and regulating the tension of the wire I am enabled to control or regulate the brilliancy of" the music at will, and the means employed is not only convenient and very effective, but also free from distorting or pinching effect upon the diaphragm.

By way of-illustrating the effect of this regulation upon phonographic music, consider the reproduction of music from a record in which the high notes of a flute and the low notes of a bass viol are recorded together- My sound box is so designed that when the tension in the wire is least, the notes of the viol will be relatively louder than those of the flute; but when the tension is greatest these low tones will be somewhat suppressed, and the flute tones will be relatively louder. By adjusting to an intermediate tension the proper balance of the tones is secured, this being subject to the control of the user of the machine. It is possible by this means not only to vary the brilliancy of the music to suit the taste of the user of the machine, but also to compensate to a very considerable extent for defects and differences in the various rec- 0rd making processes.

Some variations in loudness of the music considered as a whole is an accompaniment of the regulation of brilliancy just described, as secured by the construction illustrated particularly in Figs. 5 to 8 inclusive. My preferred arrangement, illustrated in Figs. 1 to 4 inclusive, secures a very great variation in volume of sound as well as of brilliancy or tone. As shown in these figures I employ two tuningwires 34: and 35, the lower, 34-, connecting with the diaphragm by means of the strut 31, and the upper, 35, connected to the lever 13 at a point which is directly above the center of the diaphragm. As shown in these figures the wires 34 and 35 are, for convenience. constructed from one continuous wire looped through the lug 25 and having both ends fastened by means of suitable set screws 32 in the bracket 26. This, however, is merely one expedient for securing the wires 34: and 35 and any other expedient would answer as well. In the appended claims, therefore, where only one wire is recited it never means the two strands 34: and 35 as a continuous wire but simply that one of them which responds to the terms. I mount a grooved disk 36 between the two wires as shown which acts as a connector between them. Between this disk and the lug 25 the wires are parallel to each other and to the diaphragm, but beyond this disk toward the bracket 26 they converge. The disk may he slid back and forth between the wires so as to vary the distance from. the vibration lever tothe disk. The tension of the wires is regulated by means of the thumb screw 28 as before and it is at all times of such a degree as to cause sufficient pressure upon the disk to maintain it in perfect contact with the wires at all times. The construction as described is such that neither moving the disk back and forth nor regulating the tension of the wires imposes any strain upon either the diaphragm or the fulcrum wires. although changing either the tension of the wires or the position of the disk affects the stiffness of the connection between the lever and the diaphragm. My purpose is to vary at will the stiffness of that connection so as to cause the diaphragn'i to vibrate as much as the end of the lever, or any desired portion of such amount. The mass of the disk 36 itself also has an effect upon the loudness and the brilliancy of the music produced.

Many means'forvarying at will the stifftil) ness of the connection between the lever 6 and the diaphragm 2, tor the purpose of varying the volume of sound, might be employed and I do not desire to be lim ted to the particular arrangement shown in the figures just describerh In 5, for ex:- ample, which showstheuse ofbut a single wire, I have attached the vibration lever 13 to the wire 27 somewhat teem side of the center of the diaphragm and onthe other side I provide a member 37 which may be either a weight slidably connected to the wire, or a bridge slidably connected to both the wire and the ca ing. lVith this arrangement the amount 0-: bending of the wire between the point at which the vibration lever 13 is attached and the point at lwhich the strut 31 is lined will depend both upon the tension of the wire and upon the position of the bridge, or the position and the mass of the weight.

In the structure of Figs. 1 to 4 inclusive this weight 87 may be used if desired although it is not essential. if used it would occupy a position on wire 34% as'shown.

Inspection of the various figures will show that l employ a number of ditl'erent means for varying the action of the lever upon the diaphragm, such for example as varying the length of the transi'nittlng member (or the effective part thereof), varying the tension of the transmitting member, and varying the inertia ot the transmitting member (by shifting the weight). Speaking collectively I describe anyone of these meansused, or any combination of several otthem or equivalent means as varying the stiffness of the trans mittinn; member. Any one of these means alone' will produce variation in sound volume, but to obtain wide variaticm 'in the volume together with adjust ability of brilliancy throughout the range of volume, and also to obtain good tone quality at all volumes, I prefer the arrangement shown in Figs. 1 to 4- inclusive which employ all three of the regulating methods mentioned in a very effective manner. By carefully proportioning all of the parts of the sound box (the result of much experin'iental work as well as of theoretical considerations), the regulation for sound volume may be taken care of by shifting the disk 36, while regulation for brilliancy is accomplished by adjusting the thumb screw 28. The volume is greatest when the disk is as close as possible to the lever 13 and least when it is farthest ,away therefrom. The range in volume attainable is much greater than that which is attainable by the usual method of changing the stylus from a very still? needle to a very slender 011e, although a stiff or loud tone stylus is ordinarily used all the time with my device.

I .m y, however, use any stylus that can be used on any phonograph, and regulate the loudness irom the niaximun'i of which the stylus is capable toany lesser volume desired.

.The 'inethods'ior regulating the loudness of phonograph playing that are in common use are; first, changing the stylus; second, modifying or partially closing some part of the trumpet or air passage between the sound boX and the trumpet mouth; and

third, mufliing the diaphragm. My method is entirely different from each of these, and is free from the obvious disadvantages of these methods, having no ill. effects upon tone quality, brilliancy or convenience in regulation.

The cushions 11 and 21 are alike in function, although placed between different parts of the mechanism. it is obvious that if there areobiections' t employing the cushion 11, suchas may arise from necessity ofmaking some particular kind of inechanical connection between the sound boX and the phonograph, I may omit this cushion and rely solely upon cushion 21; or under other circumstances I may omit cushion 21 and rely solely upon; cushion 11.

For use on the Victrola, for playing lateral cut records only, I prefer to employ both cushions as shown, but may design the sound box with either cushion omitted. The cushions are valuable in preventing the noises known as blast, in so far as they are due to the needle being forced out of intimate contact with the record groove'when playing unduly loud records or passages.

They are also useful in regulating the brilthe casing, a connection between wire and lever, and means for regulating the tension of the wire.

3. A sound box structure comprising in combination, a diaphr n, a wire substantially paralleling the diaphragn'i, a connection between one point on the wire andthe diaphragm, and means for communicating vibrations to the wire. at another point thereof.

a. A sound box structure comprising inv combination, a diaphragm, a wire substantially parz'illeling the diaphragm, a connec tion between one point on the wire and the diaphragm, and meanstor communicating vibrations to the wire at another pointthereof, with means for regulating the tension of the wire.

5. A sound box structure comprising in combination, a diaphragm, a wire substantially paralleling the diaphragn'i, a connection between one point on the wire and the diaphragm, means for communicating vibrations to the wire at another point there of, and a weight movably secured to the wire.

6. A sound box structure comprising in combination, a diaphragm, a wire substantially paralleling the diaphragm, a connection between one point on the wire and the diaphragm, means for communicating vibrations to the wire at another point thereof, and means for restraining vibration of the wire at varying distances from its connection with the diaphragm.

7. A sound box structure comprising in combination, a diaphragm, a pair of wires substantially paralleling the diaphragm, a connection between the diaphra m and one of said wires, a connection between the other wire and a source of vibrations, and means for connecting the two wires.

8. A sound box structure comprising in combination, a diaphragm, a pair of wires substantially paralleling the diaphragm, a connection between the diaphragm and one of said wires, a connection between the other wire and a source of vibrations, and means for connecting. the two wires, said means being adjustable along the wires to vary its distance from the connection to the diaphragm.

9. A sound box structure comprising in combination, a diaphragm, a pair of wires substantially paralleling the diaphragm, a connection between the diaphragm and one of said wires, 2. connection between the other wire and a source of vibrations, and means for connecting the two wires, said means being adjustable along the wires to vary its distance from the connection to the diaphragm, and means for varying the tension of the wires. I

10. A. sound box structure having wires in tension spread to parallelism in combinzu tion with a spreader member slidably supported between said wires.

11. In a sound box structure, a casing supported for vibratory motion, a diaphragm in the casing, a member secured to the diaphragm for imparting vibrations thereto, means connected to said member and to the casing for imparting vibrations to the casing, and means for regulating and proportioning the amount of vibration communicated to the casing and to the diaphragm.

12. In a sound boX structure, a casing, a diaphragm, a vibration lever, means for imposing a variable restraiiit upon the end of said lever nearest to the acoustic connection with said diaphragm, a relatively massive support for said lever sustained by the casing, and a cushion between the casing and the relatively massive support.

13.. A sound box structure comprising in combination, a casing containing a diaphragm, wires secured to the casing and stretched across the face thereof, a connection between the diaphragm and a wire, a connection between another wire and a source of vibrations, spreader means between said wires, and means for regulating the tension of said wires.

In testimony whereof, I have hereunto signed my name.

WILLIAM M. VENABLE.

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