US1764957A - Phonograph reproducer - Google Patents

Description

June. 17, 1930.

J. J. JAKCEJSKY 1,764,957

PHONOGRAPH REPRODUCER Filed Sept. 15,- 1926 IN VEN TOR.

A TTORNE Y.

. Patented dune l7, i93

mars "tits insane? JOHN 3'. JAKOSKY, OF LOS ANGELES, CALIFORNIA, ASSIGNOR EEO-INTERNATIONAL PRE- 'CIPITATION COMPANY, DE LOS ANGELES, CALIFORNIA, A CORPORATION 03 CALI- rnonoenarn iamnonucnn Application filed September 15, 1986. serial No. 135,504.

This invention relates to apparatus for the reproduction of music or other sounds from a phonograph record and the principal object .of the invention is to provide an apparatus for this purpose which gives a better quality of reproduction than has heretofore been obtained by any mechanical reproducing device and associated horn.

narily employed for amplifying and modu:

lating the sound produced-by the phonograph diaphragm.

A further object of the invention is to provide a reproducing device which may be easilyattached to an existing phonograph so as to provide for increased quality of reproduction.

A further object of the invention is to provide for perfect and uniform reproduction of all sounds recorded on a phonograph record, while preventing to a large extent the production of foreign noises, such as the scratching sound ordinarily present in phonographic reproduction.

In the ordinary type of mechanically reproducing phonographs heretofore used, it has been customary toemploy a vibrating diaphragm of relatively small area and to direct the sound waves produced by the vibration of such diaphragm into and through a gradually expanding horn, whereby the sound waves were amplified and the quality of sound improved. If the horn be removed from such a reproducer, the sound produced by the diaphragm is not only poor in volume, but is also lacking in quality and richness. In a reproducer of this type, it has been found that the air chamber opposite the diaphragm, which directs the sound waves from the diaphragm into the base of the horn, should not exceed a certain volume, owing to compression of air therein and resonance eifects, and

this in turn limits the area of diaphragmemployed. It has thereforewhich may be been found necessary, in order to increase the volume and quality of reproduction, to increase the length of the horn, and it has been found that the use of properly designed and proportioned horns of increased length does increase the volume of sound produced and usually also the range of frequencies of sound which may be produced. The provision of a horn of such great length, however, seems to 'mufie and distort the sound, so that the resulting sound is not a true reproduction of the sound from which the record Wat made. Furthermore, the sound emanating from a horn of this type is quite directional,-that is, it appears to come only from the direction of the horn, and is much more loud and distinct directly in front of the'horn than at either side or in back of the same. Another objection to reproducers of this type is that the diaphragms employed have a natural period of vibration and that they are much more readily responsive to vibrations ofcertain frequencies than others. The'first of these facts causes blasting or greatly increased loudness at sounds within a frequency band approximating the resonant frequency of the diaphragm, while the second causes non-uniformity of reproduction of sounds of vary ing pitch.

The same disadvantages and objections have been encountered in the designing of loud speakers for radio reception and other purposes, but in this latter field they have:

been eliminated or largely overcome by the use of substantially aperiodic diaphragms or membranes, thus eliminating blasting and non-uniformity of reproduction, and by making the diaphragmor membrane of such area that it will produce directly, without the use of a horn, sound of the desired volume and quality. Such membranes may be made of any desired size depending upon the volume of sound desired. Furthermore, the sound produced thereby is substantially non-directional, that is, it appears to travel outwardly in all directions from the loud speaker, so that it gives the effect of emanating from the whole room instead of from a single point and may be heard practically equally well from all points at equal distances from the source.

According to my invention a diaphragm or membrane of this latter type is adapted for use in phonographic reproduction, that is, a membrane which is'substantially aperiodic and of sufiicient area to produce directly without'the use of an amplifying horn, sound of suflicient volume for pleasing reproduction in an ordinary size room, it being understood that the size of the membrane maybe made large enough to produce sound of almost any desired volume. \Vhile I do not wish to be limited to any specific area or size of membrane, it is in general necessary to employ, for the purposes above mentioned, a membrane having an effective area of about 28 square inches or more and my invention may therefore be understood as contemplating the use of a membrane having an area of not less than this amount. The optimum size of the membrane will depend in any particular case upon the length of lever arms involved in the operating mechanism, and

.upon other mechanical factors, as well as upon the volume of reproduction desired. For general purposes, however, a membrane of from ten to fourteen inches diameter may usually be advantageously employed. As in the case of radio loud speakers, the use of such a membrane, without a horn, in a phonograph repnoducer does away with blasting, gives uniform reproduction of sound throughout a wide range of pitch, permits any desired volume to be obtained without distortion or muflling, and causes the sound to be more uniformly distributedin all directions instead of emanating from one point and in substantially one direction only.

The invention comprises essentially a substantially aperiodic vibratory membrane of suflicient area to produce the desired volume 'ofsound without necessitating an amplifying horn, and means for supporting said membrane in such manner as to permit substantially free radiation of sound waves therefrom and for causing the same to be vibrated or actuated in response to the vibrations imparted to a phonograph needle by the undulations in a phonograph record. The invention further com rises the use of aperiodic supporting and ampin means in connection with the mechanism or transmitting the vibrations of the needle to the vibratory membrane. Other features of the invention include adjustable damping means for regulating the amplitude of vibration of the membrane and hence regulating the volume of sound, and also counterbalancing means in connection with the supporting means for the re roducer so that the weight carried by the p onograph needle is suitably reduced in order to prevent too great a pressure of such needle against the grooves of the record.

A further feature of the invention consists in the provision of a rocking member having means for carrying a phonograph needle, means supporting the rocking member so as to permit relatively free rocking movement thereofabout one axis, due to vibrations imparted to. the needle by the recorded undulations on the record, but to relamembrane in such manner that rocking movement of the member in the first-named direction is effectively transmitted to the membrane, while any rocking movement which may occur in the second named direction is not substantially so transmitted.

The accompanying drawings illustrate embodiments of my invention and referring thereto: i Fig. 1 is a vertical section of the reproducin once.

ig. 2 is a partial horizontal section on line 22 in Fig. 1.

Fig. 3 is a section on line 3-3 in Fig. 2.

Fig. 4 is a section on line 4-4 in Fig. 2.

Fig. 5 is a section on line 55 in Fig. 1.

Fig. 6-is a vertical section of a modified form of the invention.

In Fig. 1 part of an ordinary phonograph cabinet is indicated at 1, within which isthe cabinet and is provided with the usual disc-shaped plate 4 for carrying and rotating the phonograph record indicated at 5. The phonograph is further understood as being provided with the usual means for stopping and starting motor 2, for regulating the speed thereof, and for winding in case of a spring-driven motor.

The reproducing device'comprises a vibrator membrane 7. of suitable aperiodic materia such as paper formed in the general shape of a double cone, that is to say two cones 8 and 9 joined together at their bases as at 10. As shown, however, the lower cone 9' is preferably somewhat truncated and a supporting plate 12 may be mountedso as to extend across, or partly across the opening thus afforded, said supporting plate being secured to the lower edge of cone 9, for exam 1e by means of ring 13. In the case of a ouble cone sup orted in this manner, the effective area of t e membrane may be considered as i-substantially the area of the upper cone, or in general the area of the cone to which the operating mechanism 4 is connected. The lower cone, while it undoubtedly does roduce some sound, serves mainly to flexibly support the upper cone.

The reproducing device may be mounted at the outer end of supporting arm 14 which is secured forexample to the supportin plate 12, said am being pivotally mountetf at its other end on pivot 15 mounted on yoke 16. Said yoke is mounted so as to swing hori- III zontally as by means of pivotal supports 17 on a supporting bracket 18 mounted in a suitable position on the phonograph cabinet. A counterweight 20 may be mounted on counter-weight arm 21 which is also pivoted on pivot 15 so as to permit movement of the arm.

. in effective counterbalancing position. When however the reproducing device is tilted upwardly to the position indicated in dotted lines at 25 for the purpose of changing the phonograph record or inserting anew needle m thGdGVlCG, support ng arm 14 moves away from engagement with shoulder 22 so that the counterweight is allowed to fall slightly until shoulder 22 comes into engagement with the vertical portions ofyoke 16 so that at this time the reproducing device is permitted to swing vertically independently of the counterweight. A handle 26' may also be I secured to the supporting plate and may extendforwardly beneath the vibratory membrane 8, into a position in which it may be easily grasped for lifting the reproducing device ed the record.

A substantially rigid rocking lever member 27 may be mounted between aperiodic supporting and damping members such as rubber pads 28, there being one of such rubber pads below and one above each end of the lever member 27, and said supporting means being held in position to support said lever member by means of clamping plates or straps 29 secured to supporting plate 12. The rocking member 27 may be provided with a' needle-carrying member 30 which -may' be integrally formed therewith or rigidly secured thereto in any suitable manner, said needle-carrying member being adapted to receive and hold. an ordinary phonograph needle or stylus 24 at a suitable inclination to the face of the record, in the usual manner of such devices and being provided with a retaining screw 31' for holding the needle in osition therein. The needlecarrying mem r 30 is preferably mounted substantially on the axis about which the rocking member 27 is adapted to rock or vi- 'brate, which axis is substantially the longitudinal mid-line ofsuch rocking member or the line joining the mid-points of the supporting and damping means therefor as indicated at w-a: in Fig. 2. As clearly shown in Fig. 2, this axis of vibration lies in the plane of the' needle 24.

Auxiliary damping means are preferably provided so as to permit an adjustment of the degreeof damping to which the rocking member or or vibrating member 27 is subjected. For this purpose said rocking member may be provided with a laterally projecting arm 33 and said arm may be held between two resilient aperiodic damping members such as rubber pads 34 which are in turn held in place between adjustable clamping arms 35. Said clamping arms may be mounted as at 36 on the supporting plate 12 and an adjusting screw 37 may be provided which has reversely threaded portions adapted to engage respectively in the upper and lower clamping plates 35 so that turning of said adjusting screw in one direction serves to draw the clamping plates closer together and increase the damping action while turning of said screw in the other direction serves to spread the clamping plates further apart and decrease the damping action.

A translating member such as a light flexible wire indicated at 38 may be connected at one end to the rocking member 27 as indicated at 39 and at the other end to the apex of the upper cone 8 of the vibratory membrane 7. By reason of the flexibility of such trans lating member it is practically incapable of transmitting motion in any other direction than longitudinally with respect to itself. In order to provide for relative adjustment between the vibrating membrane and rocking member 27, the wire 38 may be adj ustably connected' to the membrane and for this purpose said wire may extend through sleeve 40 securedto the membrane and a set screw 41 may be provided for holding the wire in any desired position in which it may be set with respect to sleeve 40.

In the operation of the above-described reproducing device for reproduction of music or other recorded sounds from a phonograph record it will be understood that the record 5 is placed on the carrying plate andthe same is set in rotation 'by operation of the motor 2 in the usual manner of such devices. The reproducing device is then lowered onto the record in such manner as to bring the needle indicated at 24' into engagement with the initial groove of the record and such needle is thereby caused to traverse the grooves of the record. The passage of the needle over the undulations of the record causes the same to vibrate in a direction corresponding to the adapted for use with records in which the direction of cut is horizontal and transverse to the grooves of the record so that the vibrating member 27 together with the needle carrying member secured thereto is caused to rock or vibrate in a substantially vertical lane about the axis H above referred to. cause of the substantially aperiodic nature of the rubber supporting pads 28 and the rubber damping pads 34, such rocking movement of member 27 is substantially aperiodic, that is, such member is substantially equally susceptible to vibration at frequencies of a wide range. It will be seen that since the point of connection 39 of wire 38 to rocking member 37 is horizontally spaced from the axis :vw,

the wire or translating member 38 will caused to move alternately up and down in response to the rocking movement of member 27 and will therefore cause the vibratory membrane 7, including both the u per and lower cones .8 and 9, to vibrate at a requency corres onding to the frequency of the sound recor ed on the record. The amplitude of vibration of the vibratory membrane will be to be produced which correspond faithfully in frequency and relative intensity to the.

- sound recorded-on the record. Due to the aperiodic nature of such membrane it is sub-' stantially equally susceptible to vibrations of widely varyin frequency, and there is no tendency for t e same to oscillate or ,blast at frequencies corresponding to. sounds of certain itch as is the case with the usual type of iaphragm employed in phonograph reproducers. Furthermore, the sound produced by the vibrating membrane does not pass through an horn and is consequently permitted to radiateor travel outwardly unlformly in all directions. The sound therefore gives the efiect of simply filling the room rather than emanating from one certain point in the room as was the case with the horn type reproducer.

It will be seen that any accidental .vibration imparted to the phonograph needle in a direction other than the cut of the record, will be much less effectively transmitted to the vibratory membrane than are the vibrations in the direction of such out. For example, vibration of such needle in a vertical plane would tend to move the rocking memr bodily up and down or rock it aboutthe horizontal axis YY (Fig. 2). j

Both of these motions 'of the rocking member are, however, substantially prevented or relatively restricted as compared with the rocking motion about axis H due to the relatively large distance between the su portto axis Y-Y. Furthermore, an rockin motion which may occur about ms Y--Y is not appreciabl transmitted to vibratory membrane 8, note the fact that the point of connection of. link member 38 to rocking member 27 is substantially on such axis.

stantiall aperiodic 'of faithl u porting plate and sp Another modification of the invention is illustrated in Fig. 6. In this form of the invention the vibrating membrane 7 comprises as shown a'single cone of light materialsuch as paper or parchment which is free at its outer ed 'e and is secured at its base or center to arigi as before 1s connected to rocking member 27 at a point spaced from the effective axis thereof. Such cone preferably has an area as above defined. A su porting plate 12 is provided-in this case as E derstood that such supporting plate may be mounted at the outer end of a supporting arm similar to that abovedescribed or may be suitably supported in any desired manner. In this case however the rocking member 27 toin or translating member 38 which efore and it will be unther with the aperiodic supporting pads 28 fabric such as wire screen or silk indicated at 46 and 47 may be mounted on said housing frame respectively below and above the vibrating cone 7, so as to permit free passage of sound therethrough concealing said cone.

The operation of this form of the invention is substantially the same as that above described with the exception that in this case the vibrating membrane 7 moves up and down bodil in response to motion imparted to link mem r 38 1n the manner aforesaid. Since said membrane is of very light weight and is free at its outer edges its motion is suban t e same advantages 1 reproduction of sounds of va ing fr uency are therefore realized. 'l ze. porous abric at 46 and 47 is sufliciently open to permit substantiall free radiation of sound waves from m rane 7, while serving to rotect said membrane from injury.

claim:

1. An apparatus for reproducing sound from phonograph records comprising a supportm plate, a. vibratory membrane mounted on'sai supporting plate and formed of such material and of such sizeas to be substan-' tially aperiodic, a rocking member disposed in a plane substantially arallel to sai sup- 4 aced laherefrom and provided with needle holdi means adapted to hold a needle in a p ne substantially perpendicular to said rocking member aperiodic resilient means supporting rocking member on said supporting plate andsodisposed as to permit rocking movement while protecting and v of said rocking member about an axis lying substantially at the intersection of the plane of said rocking member and said perpendicular plane in which the needle is dis osed while substantially preventing motion 0 said rocking member about an axis perpendicular to said first named axis and lying substantially in the plane of said rocklng'member, and link means connected at one end to said rocking member at a point spaced from said first named axis and substantiall in the line of said axis perpendicular to sai first named axis, said link means extending substantially perpendicular to' said rocking member and being connected at its other end to said aperi-,.

odic vibratory membrane.

2. An apparatus as set forth in claim 1,

\ said aperiodic resilient means comprising pads 0 3. An apparatus as set forth in claim 1,

said rocking member being provided with an arm projecting therefrom at the opposite side of said first named axis from the point of connection of said link means, and said apparatus further comprising aperiodic resilient means embracing said arm and means for adjusting the compression of said last named aperiodic resilient means so as to control the damping efiect thereof onsaid rocking memher,

In testimony whereof I have hereunto subscribed my name this 8th'day of September,

JOE J. JAKOSKY.

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