US1566413A - Means for recording sound waves - Google Patents

Description

-J. MASSQLLzE `E'I'Al.

MEANS FOR RECORDING SOUND WAVES 'INVENTORSz Qvroeneys J. MAssoLLE 5TM. l

MEANS' Fon RECORDING Suw ymvs Filed April 4, 1921 2. Sheets-Sheet 2 FI G. 5

A' Sq. f I fr v so L v I 52 Y 53 V.lnlvenorezr Jos EPH Massa/f HA Ns V067 (/oEF Eis/6l.

Patented Dec. 22, 19.9.5.`

unirse srares Partnr oir-Fica JGSEIE'I-I lVf-IASSOLLE AND-JDSEF ENGL. OF GRUNEVALD, AND HANS VQGT, OF BEHLN- SCHNEBERG, GERMANY,'ASSIGNORS T0 TR-ERGON LIIVTED, 0F ZURGH, SW'T- ZEELAND.

Application filed April 4, m21.

To GU10/10m if. may concer-14 lie it linown that we, losnru Massomni, .loser Thun, and l-lANs Your, citizens of the German Republic, residing. the first and second at Grunewald. the third at Berlin-Schoneberg, Germany, have invented certain new and useful Improvements in Means for Recording/Sound lYaves, of which the following is a specification.

lu the recording of sound waves it is necessary, for example for optical acoustical operations (speaking film, granuuihonetic musical performances, acoustic advertisements. and the like) to fix the sound w'aves in order to be'able to utilize the recorded symbols for reproduction.

This invention relates to an arrangement for recordingsound waves in which the fixation on a moving film is effected photographically in such a manner that the lsound waves act on a pencil of light raysin accordance with their .frequency and intensity.

l'ior this purpose the arangrement is so constructed that the energy of the sound is coinpressed and acts on a mirror mounted on one side. This mirror i. e., a diaphragm having a light-reliectine' surface, has preferably a high individual frequency 'and is of small dimensions so thatsa maximum impressionability and great angle of rotation are obtained.

The invention may be practiced by the use of one reflecting;` diaphragm, or of several reflecting' diaphragma/against which the sound waves will impinge and from the reflecting; surfaces of which light rays will be refiected. These reflected rays will be utilixed. for example, by recordingy the varying innige photographically ou a sensitized ihn, alv record thereby being' formed which corresponds to the. variations of the origina-l sound Waves.

With diaphragnis secured at one edge only, various advantages are secured. Thus,

a minimum of poweris required to obtain a desired movement of the diaphragm; a

smaller diaphragm may be used to produce the same deflection, than with a diaphragm otherwise z uounted, injith the same'erertion Sera No. 458,633.

ot' power upon it; and the light rays reflected from the reflecting' diaphragm vmay be kept parallel, with each other, because the diaphragm remains plane upon deflection, in

contradistinction to a diaphragm supportedO lVhen a plurality of reiiecting diaphragms are used, they preferably have different individual natural rates of vibration, so chosen that they will reinforce sounds re"eived 'by the diaphragme throughout a Wide range lhe construction also 1s preferably such that ay damping effect is obtained at the da` phragrms. Accordingly the recorded curve would have various resonance peaks, corresponding to the tones and overtones to which the various diaphragms respond, but for the fact that these peaks are somewhat iiattened hy the damping effect, whereby the resultant curve-more corre tly corresponds to the original sound Vibrations.

The invention, in addition to its use for recording sound on sensitized surfaces, etc., may be utilized for other purposes, as for example, for causingthe acoustioallycontrolled light to control the internal resistance of a light-sensitive cell.

The invention consists in arangements and combinations in acordance with the foregoing, all as will be more fully described hereinafter and particularly pointed out in the appended claims.

In order that the invention may be more clearly understood, attention is hereby directed to the accompanying drawings, forming part of this application, and illustrating; certainembodiments of the invention. In the drawings, i i

Fig. l is a diagrammatic sectional view illustrating the use of a single reflecting diaphragm g Fig. 2 is a similar View, showing two refiecting diaphragms jointly covering the open ing; y

l- Fig. 3 is adiagrannnatic, parti-afl, enlarged through a modified torm ot apparatus 'in which a plurality of reflecting diaphragme are used si'iccessively; and

Fig. 7 is a view similar to that of Fig'. #12, but showing a light-sensitive cell in place of the sensitized film, to receive the acoustically-varied light.

The invention may be carried out. tor cte ample by causing` a collecting device 0 (sound horn see Fig. 4') which embraces great angular ranges to concentrate the energy ot' the sound on a reflecting diaphragm s1. This diaphragm is for example of rec tmgular form and is clamped tast on one side as shown b v way ot' example in Fig.' l. lt practically completely covers the orifice oft' the collectingl device O. The dimensions ot the diaphragm al are preferably such that the highest possible individual trequency is ensured and that, owing to the small mass ot' the diaphragm aV pcrceivable deflection is secured even with small sound energy. An

individual frequency may be used (e. g. ot' 'i2000 to 15000) which lies beyond the t'requencies usual in ordinary sound operations.

'The invention may also be carried out so that, instead otl the small mirror 31 several, tor example according to Fig. Q two mirrors ,al and s2 are used Which are mounted each at a point oi its circumference opposite the point ot the circumference at which the other mirror is fixed, so that they deflect, one, in the direction of a right hand rotation, the other, in the direction of a left hand rotation. Their dimensions are preferably so chosen that they possess different individual frequencies. It is ot advantage to frive the one diaphragm comparatively low individual vibration so that it acts specially on the individual vibrations of the vowels and their diphthongs. lts 'damping is suitabl so chosen that the higher harmonics o its `ibrations will not cause a disturbing effect. '.lhis is effected for example by the suitable choice of its distance from the attachment trame i' (sce Figs. l and The second rctlectif fr diaphragm is made of such dimensions, that it reproduces the high frequency vibrations ot the consonants and sihilant rcfiecting surface of the diaphragm or mirror s1, Fig. l, or the tvvov diaphragms 31 and s2, Fig. 2, and be reflected thereby, the reflected light being directed, for example, by a number ot' prisms p, to produce an image of the light source on a slit sp. The inner edges ot the two mirrors off Fig. 2 determine on the slit two limits g1, g2, (Fig. 3), between illuminated and unilluminated parts ot the, slit. Their distance apart can be fixed by tilting the surfaces ot the mirrors with relation to each other.

According to the state ot movement of the diaphragme the limits of the light displace themselves on the slit and efl'ect on a lm f, moving rapidly behind the slit, transverse blackenings ot ditlerent lengths.

ln order to increase the sensitiveuess ot the arrangement it` is further of advantage to prolong the path ot' the rays off light from the reflecting diaphragm to the slit through which the image is to be projected. ln order, however, to avoid making the apparatus too long, the course ot the rays may be bent repeatedly by means ot total reflecting prisms (p in liig. t.) or hy means of simple mirrors.

ln contradistinction trom the form of construction described the arrangement may also be made in such a manner that the light pencil is rcflei'ted successively by a plurality ot small retlecting diaphragrms, ot different individual frequencies whereby merely an area of hlaekenings is produced on the film which shows the variations ot the lower frequencies and over it superposed in correct phase the high frequencies. This form is described more fully hereinafter, in connection with Fig. 6.

lll/'ith such devices tor recording;l sound Waves by optical means with the aid of a pencil of light influenced h v the .sound energy, comparativelv small angular detlections of the oscillating' mirror may he advisable. l'n order however to obtain thus sufficient amplitudes ot the light pencil at the recordingV point. there hare heretofore been used correspoudiugly long light pointers such as are used iu .similar mirror rccorders (mirror galvanometcr etal. For acoustical recordingr apparatus sacd ar- 5 for example may be of approximately cubical shape.

An example of constructional form of this :term or feature ot the invention is oliagrai'i'i-A matically shown in the Fig. 5. The sound l@ Waves, collected by the funnel shaped piece r, strilre on the reflecting diaphragm 30. The pencil of rays emitted from a source of light l and concentrated by the optical system on the small mirror Sm is caused by l the oscillations of so to malte a transverse movement which is indicated by the transverse arrow, continues in the direction indicated by the arronT and is reflected successively .by the mirrors si, e2, e3, s4. The

amplitudes ot' the ray of light which are rather large owing to the longoptical path are then received upon the light sensitive strip f, Instead of the mirrors, other optical means may also be used for bending the path ot the light rays, e. e'. total reflection ,35 speaking, tivo detects.

prisms and the like. By the arrangement ot' the mirrors s1 to s* the number ot' which may naturally be smaller or greater, the dimensions ot the apparatus may be so selected 0 that it acquires a compact form tree from w etc.) in which case this tact is manifested by a distortion of, the true values of inten sity otl the sound at all frequencies which coincide with the :fundamental tone of the vibrating' number or its overtones. (lr the individual frequency ot the vibiatincY element is intentionally displaced beyond the. range ot the sound waves which are to be received in which casey no distortion can be detecteiil," but. the amplitudes of the oscillah ing element are comparatively small. rl`he latter way has heretofore not been practically realized. but it would he iulvantzigreoiis, in order to iii; sibilant sounds, 'lineness ot consonants`v etc. VY'Yitli such an :'u'rancemcnl, however, the recordingv oi the lower sound vibrations (vowel tones and diphthongs) would be insuilivicntly executed iu-corf'liugfly, in this invention. ,iifdiii'elm t method is tol-I lowcd -which nature has' aire id v indicated in ,u .the human car. iever i elements are .l which are able ol :illal'i/.in and which arc consti as lo `torni reflecting easily inliuenceci dii )l iig-fins ot the smallest pos- G s ile mass, the requirements et the registral 'tion of the' highestv frequency being coni,-

plied with by the selection oit a correspond.- ingly higher individual frequency of one o1 the small mirrors. The remaining reflecting diaphragn'is are successively so selected that they possess suitably ditlerent individual oscillations in order to react strongly to vowel tones etc. ln any case however for a reason above mentioned the dan'ipiugr ot the diapliragn'is must besuch that the above mentioned desired ellect is counteracted to a sufiicient extent. On 'these small mirrors, whose axes ot' rotation must be all parallel, there is reflected successively a pencil of' rays, which issues from a suitable sourcel of light and is concentrated by an optical system on the plane where the recording takes place. The oscillating movement ot each ot' the small mirrors is transn'iittcd to the pencil of light. The small mirrors themselves are all mounted next to one another at one location in the space in order to allow the sound vibrations to act on all the mirrors in` one and the same phase.

Fig. 6 shows diagrammatically by Way ot example a practical construction ot' the apparatus.- Gn the bottom u of the sound conductor t diaphragms sl s2, s are mounted which possess different. individual natural rates of vibration and are all provided with;

reflecting surfaces. the diaphragms all being attached at one side only. By means of a source of light and of an optical system 0 a'pencil ot parallel rays is thrown succesw sively with the aid of reflectors r1, 'r2 on to the oscillatingsmall mirrors. The suitably controlled ray then acts upon the plane e which represents a light sensitive film or` il' the oscillations are to be also electrically inY tensiiied, which may be a selenium or photoelectric cell. In the latter case the rays ol licht may imping'e against thel reflecting diaphragme simultaneously.

The dan'iiiing oit the diaphragmsmay be so arranged as to somewhat decrease the sharpness of the resonance peaks in the acoustic llO curve. as stated. rlhis dampingl niay be ac# Y* inbeiiore 'been described could also he used At'or other technical purposes (Wireless telephony and the like). 'this could he donc in all such cases where sound Waves have to be transformed into electric oscillations or Where an acoustic phenomenon has to be utilized electrically. la such cases a cell. which is sensitive to radiation (e. g. a photoelectric alkaline metal cell or the like (is employed, as shown in Fig. 7, for example). From the oscillating' mirrors of the acoustograph more or less light lis thrown in the rhythm vof the acoustic AWaves upon the photocell and varies rhythmically its electrical resistance. This tact can be utilized in the manner hcreinbefore described for controlling high frequency oscillations or in any other convenient manner. The apparatus described might represent in connection with a high frequency circuit and With an antenna, a sender for wireless telephony.

l. ln acoustic apparatus, the combination ot' a fixed nieinber'having an orifice, a small diaphragm, covering saidorifice and attached to said member at one'side onlv, and having a reflecting surface. said diaphragm being adapted to be set in movement by sound waves impingring against the same, and means 'for directingr a ray of light upon the reflecting surface of the diaphragm.

Q. ln acoustic apparatus, the combination of a sound collecting' device havingr an orifice, a diaphragm secured aty one side only and substantially coveringthe orice of said device` and having a refiecting surface on the side opposite to that against which the sound waves inipinge, means tor projecting a ray of light on the reiecting surface of the diaphragm, and means upon Which the reflected light falls.

3. ln acoustic apparatus, the combination of a supporting member. having adjacent openings therein, a plurality of diaphragms covering said openings. exposed to sound waves on one side and havingA reflecting surfaces on the other side, said diaphragms having: different individual frequencies, a source tit-light. and means for directincf a beam of light therefrom against the reflecting sur- `laces of each of said diaphragms in succession` and from the last ot said diaphrag'ms to a desired point.

4. ln acoustic apparatus, the combination ot a supporting member, a. plurality of small diaphrae'ms secured at one side onlv, exposed to sound ivaves on one side thereof and having' reflecting surfaces on the other side said diaphragms harina diti'erent individual frequencies. and means for directing light aoainst said reflecting surfaces to be reflected thereby. e

f. dcansA lor recording lsound wares coniprisingf a device t'ol' collecting' the SOlllld energy and condensing the same. and a small refiectine diaphragm possessing' high individual frequency. said diaphragm being attached at one side only and exposed to the action oi? condensed sound energy.

(l. Venus for recordingr soundtvaves. comprising a device for collectingr the sound energy and condensing the same. and a plurality ol thin and small reflecting dia- Vphragjlfn'is ixedly secured at one side only and exposed to the action of the condensed sound energy.

7. Means for recording sound Waves, com prising a device for-collecting the sound energy and for condensing the same, and a plurality of small reflecting diaphragme, possessing different individual frequencies, said diaphragms being rigidly attached at one side only and arranged so as to be damped and exposed to the action of the condensed sound energy, whereby to record the structure of the lower vovvel vibrations and of their diphthongf and also the con sonantal sihilant sounds.

8. Means for recording sound waves comprising in combination with a device for collecting the sound energy and lor condensing the same, a plurality of small rc- ,lecting diaphragms attached at one side only exposed tothe action of the condensed `sound energy. and a source of light emitting a pencil ot light to be rctiected in succession by the several diaphragms so that the light pencil reflected from the diaphragms may make a record on a light sensitive band.

9. Means for recording sound Waves comrising in combination with a device for col acting the sound energy and Jfor condensing the same, a plurality of small redecting diaphragms possessing dierent individual irequencies and rigidly attached at one side only and so as to be damped and exposed to the action of the condensed. sound energia.

a source of light emitting a, pencil ot light to' be reflected lin succession by the several diaphragms so that the light encil retlected from the diaphragms recor s a range of blackening on a light sensitive band, and several fixed mirrors for bending the ath of the licht. pointer for the purposeohtaining a more compact arrangement'nhicli is less sensitive to concussion and individnal oscillations.

10. Means for recordingr sound waves come prisingl in combination with a device 'for col lecting the sound energy and for condensing the same, a plurality 'of small reflecting diaphragms attached atmone side only and exposed to the action of the condensed sound energy, a source of light emitting a pencil of llti H faces on the other side, said diaphragms havphi-agms in Succession, and from the last of ing different individual frequencies, all 0f said diaphmgms t0 a desired point. said diaphragms4 being'secured at one side In testimony whereof' we affix our signzi- 10 only, and all having parallel axes of rotatures. l 5 tion, la source of light, and means for di- JOSEPH MA SSOLLE.

recting a beam of light therefrom against DR. JOSEF ENGL. he reecting surfaces of each of said dia- HANS VOGT.

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