US1778374A - Electric music instrument - Google Patents

Description

Oct. 14, 1930 E. SPIELMANN ELECTRIC MUSIC INSTRUMENT Filed Feb. 8. 1928 gwumtw m m m P 5 mv P 5 W. m A W .V a, m mm Uh O MMW m I 1 wwve0 0% a w w w M W P Patented a. 14, 1930 PAreNr OFFICE A EMERIGE SPIELMANN, OI VIENNA, AUSTRIA.

nnnc'rarc MUSIC msrauunn'r Application filed February 8, 1928, Serial No. 252,861, and in Austria February 11, 1927.

' This invention relates to an electric music instrument in which the current im ulses acting onto a telephone receiver (lou speaker) are produced light at sound frequencies of photoelectric cells by means of slotted rotating screens. Such music instruments with release of sounds b a key board have already been suggeste but were not fit for artificial purposes since they did not admit tuning of the notes or equalizing the same.

According to this invention the tuning of the notes to arbitrary irrational frequency relations is effected (as'f. i. necessitated by the key board of an instrument the octaves of which are as usual subdivided into twelve half-notes) in that each half-note of the gamut of an octave is produced by a separately driven rotating screen commanded f. i. by belt-drives from a common main shaft. By appropriately dimensioning the belt drums any desired speed ratio of the single screens may be obtained which moreover may be corrected if necessary by adj ustingthe' diameters of one or the other drum on turners lathe.

Since the sound frequencies of the harmonics of a note in the different octaves are in the ratios of the powers of the number two it is a'further feature of this invention that all the harmonics of a certain note are produced'byone and the same screen which to this purpose bears concentric rows of slots or the like the number of which is doubled from row to row (preferably outwards).

The keys of the music instrument are, con-- nected to electric resistances in a manner known as such to partially switch on or off these resistances by more or lesspressin'g down the key and thereby increasing or diminishing the current intensity and consequently the sound intensity. A new feature according to this invention consists in that ,the e'fiicient length of the .resistance means (coils or the like) is regulable by means of a contact slide or the like, vso that each note can be regulated individually. Thusit is possible to compensate the unequal light emission of the electric light sources and the unequal sensibility of the photoelectric cells and y intermittently exposing to of the frame. (1 are bolts fixed at the lower thereby to obtain equal sound intensity and timbre with all notes and half-notes when equally acted on the respective key.

Further features of the invention will be seen from the following specification and drawings wherein Fig. 1 is a side elevation of my electric music instrument, partly in section, Fig. 2 is a front elevation thereof seen from the side of theplayer. Fig. 3 is a sectional view C0 of the key board mechanism in a side elevation on an enlarged scale as compared with Figs. 1 and 2. Fig. 4 is a diagrammatic view of two of the rotatable screens with adjacent glow lamps and photo-electric cells,

showing also the electric connections from the latter to the current sources, loud speaker and key contacts. Fig. 5 is a side elevation and Fig. 6 is a front elevation of the rotatable screens with belt drives and (in Fig. 6 only) of the motor and the-master gear. The scale of Figs. 5 and 6 is between that of Figs. 1 and 2 on the one hand and Fig. 3 on the other hand. 1

In Figs. 1 and 2 A are the flexible current supply lines between the key board B and the glow lamps referred to hereinafter. C is the detachable cover of the-music instrument, D is the storage battery serving as source of electric current for the electromotor referred to hereinafter. Parts n, o and w of Fig. 1 will be referred to hereinafter, when describing Figs. 4, 5, and 6. P, P are two pedals for the general regulation of thecurrent intensity for the supply of the glow lamps and for. the fixing of the keys which have played on in their low position, respectively. p

One of the current supply lines A is also shown in Fig. 3,'wherein E, F, G and H are different parts of the key board frame, E being the rear plate, G being the front plate thereof and H being such part of the frame, on which the resistances referred to hereinafter are fixed while part F serves as a rest or stop for the keys. a is an extension of the key, 5 is a band spring pressing onto the said extension a and onto the part E 1'. Apparatus side of the keys. e are levers fulcrumed at the key board frame. f are band springs connected to the levers e, g are ad usting screws connected to the springs f. h are armatures .attached at the lower sides of levers e. i are bare' resistance wires, hare slide contacts contacting the said resistance wires a. Z are electromagnets arran ed opposite the armatures h referred to a ove.

Referring to Fig. 4, m is the battery serving as current source for the glow lamps n, 0 are rotatable screens, p are photoelectric cells, 9 is a storage battery serving as current source for the above photoelectric cells. 1' are low frequency transformers, the secondary coils of which are arranged in the circuit of the valve amplifier s and the loud speaker t.

In Figs. 5, and 6, a tl ,--u ,u are pulleys, o is an electromotor, w are bevelled pulleys of a regulable transmission (master gear), :20 are the belts connecting the pulleys e0 ta -to the corresponding pulleys on the discs, 0, y are the supports of the photoelectric cells 32 and the glow lamps n, respectively, and z are the individual shafts of the different discs 0.

Hereinafter 'the different parts of my electric music instrument are described as such as well as then mode of cooperation.

for the production of a sound frequent mtermz'ttent ewposumc to light of the photoelectric cells An electromotor '0 (Fig. 6) is connected by means of a regulable transmission or to a shaft on which twelve pulleys u; to a are arranged (in the drawing four only being shown). Each of these pulleysmakestorotate y means of a belt 00 one of twelve pulleys preferably of equal diameters each being arranged on a separately fulcrumed shaft 2 and connected to discs 0, the speed ratios of which corresponds to the twelve sounds of an octave by appropriately dimensioning the pulleys u to a Th to light. As indicated in Fig. 5 radial slots are provided on eight concentric rings there-,

on 1. e. on the innermost ring one slot, on the second ring two, on the third ring four, and on the following rings always double the number of slots appearing on the preceding one, the outermost ring having 128 slots. Preferably these discs 0 are produced photographically on films, on which the slots appear as translucent strips on a black ground. At both sides'of these discs 0 supporting boards 3 are arranged (Fig. 4) on the one side of which eight electric glow lamps h are arranged in such a manner that the light of each of these eight lamps passes -through a different row of slots of the disc 0. On the other side of the discs 0 photoelectric cells p are arranged opposite to the glow which the loud s e discs 0 are impervious tances from the fulcrums.

lamps. When the discs 0 rotate each of the glow lamps n illuminates the opposite photoelectric cell intermittently with a frequency which differs according to the varying number of slots and the different number of revolutions of the discs: the ratio of intermittence of the glow lamps arranged adjacent one and'the same disc is that of one and the same sound in eight succeeding octaves, whilst the ratio of intermittence of the twelve groups of glow lamps is that of the frequencies of the twelve sounds within an octave. By means of this apparatus one may produce light intensity variations corresponding to 84 sounds or eight octaves and the corresponding variations of resistance of the photoelectric cells. Each of these photoelectric cells is connected to a circuit of the battery 9 in series with the primary coils of low frequency transformers r the secondary coils of which form part of a circuit in eaker t is arranged besides the valve amplifier 8 (Fig. 4). The variations of resistance in the photoelectric cells which occur when the latter are intermittently ex osed to light, produce variations of current orce which are transformed into alternating currents and transferred to the circuit of the loud speaker, for conversion into audible sounds.

[1. Key board and mechanism rame. On this extension a an S-shaped band spring 6 is fixed in such a manner as to force the key into the horizontal position, which is limited by the extension a bearin on the key board frame or by the strain o a filament (not shown) the length of which is adjustable by means of screws. At the lower side of each key an adjustable bolt 03 is arran ed which transfers the movements of the ey (when being played on) onto an one armed lever e arranged below each key. To eliminate the difference of angles of motion of the black and white keys the respective ad justable bolts d are arranged at different dis- Every lever c is connected with one end of a V-shaped band spring 7 the other end of which is connected to ad usting screws 9 which enable the band springs f to be lifted or lowered, respectively. The springs fbear on insulating strips i having bare resistance wires wound thereon, the number of such strips fixed side by side'on the frame H being equal to that of the keys. In the state of rest each band spring is adj usted by means of the screw 9 in such a manwhich the key is pressed down when being played on the lever e displaces more or less the band spring f (see F ig; 3, in dotted lines) so that by the band springs rolling on the respective resistance wire 21 more or less resistance is switched on or off according to the pressure on the key. Each of the band springs is continuously connected to a circuit supplied by the battery m and leading from the screw A, slide contact is, to the resistance wire 2' and band spring f. To each of these circuits one of the above said glow lamps n is connected and by means of the arran ement described each glow lamp correspon in to the respective key may be not only switc ed on and off by pressing down the key but also the intensity of the current supply and thereby the intensity of light thereof may be varied. A particular advantage of the described mechanism is its absolute noiselessness when being acted on, which is an important requirement for each mechanism connected to a music instrument. By means of the slide contact is each note can be separately adjusted as to sound intensity and timbre.

HI. Assemblage that the instrument may be put below the key board of the piano in such a manner that the two key boards fit together. For this purgose also the key boardand mechanism-box is adjustable in height and therefore the current supply lines leading from the glow lamps n to the screws A are flexible.

Fig. 2 shows the two pedals P arranged on the instrument. The left pedal acts on a general regulating rheostat in the circuit of the battery m. By pushing this pedal the current supply to the glow lamps is throttled and thereby the force of sound diminished. The right pedal connects-the current into a circuit supplied by the current source of the electromotor e, which circuit contains the coils of the electromagnets Z shown in Fig. 3. Armat-ures consisting of soft iron are fixed on the lower sides of the levers e. When the right pedal i pushed down an electric current flows through the coils Z of the electromagnets so that all the levers 6 having previously been pressed down are'maintained in their lowest position by the attraction on their respective armatures it. As long as the right pedal is pushed down the sound, corresponding to the keys acted on, endures without continuing to press down the keys. In the casing of the instrument there are further the necessary low frequency transformers r, the valve amplifiers s, the batteries D and a device for regulating the speed of the electromotor.

The absolute sound pitches which may be produced by this instrument dependsetting aside the dimensions of the apparatusespecially on the number of revolutions of the driving motor. It is therefore necessary before playing the instrument to regulate the number of revolutions of the motor so that the sounds produced are in accordance with the keys of the key board. This regulation is, however, very simple since by correct regulation of a single sound all other sounds are automatically also correct; moreover this instrument has the entirely novel feature, that one may transpose a music piece intoany desired pitch by varying the speed of the motor without changing the mode of playing.

The electric music instrument according to this invention may be also used as equivalent for any known music instrument by the following modification:

It is well known to register sounds photographically by arranging in series a telephone and an electric light source by means of a transformer, and to photograph on a moving film the light variations caused by the sound oscillations. This method is utilized in speaking and music playing films, on which language or music is photographically registered in its connection.

The modification of the apparatus consists in utilizing discs 0, the concentric rings of which do not bear the above said slots but photographic registrations of the single tones of music instruments. The loud speaker of an electric music instrument having such discs produces, when being played, tones having the timbres of the music instrument the tones of which are registered on the discs.

In especial embodiment of the electric music instrument three key boards are rovided like those of an organ, correspon ing to three apparatus driven by one and the same motor. One of these apparatus comprises discs 0 with photographic-sound registrations of string instruments, the second one comprises such of wood wind instruments, and the third that of brass instruments. With such an instrument a single musician is able to lay a complete orchestral piece with all tim res and dynamic shades thereof.

I claim as my invention:

1. An electric music instrument comprising in combination electric current sources, a number of electric glow lamps, a key board adapted to individually connect said glow lamps with one of the said current sources, photoelectric cells arranged opposite said glow lamps, a telephone receiver connected to one of the said current sources and to said photoelectric cells, a motor, a series of gear drums adapted to be driven by the said motor,

a series of partially translucent and partially opaque screens arranged between, the said glow lamps and the said photoelectric cells, gear drums individually connected to the said screens and adapted to be driven at individual speed from the gear drums of the said series of drums.

2. An electric music instrument as claimed in claim 1 in which the diameter ratios of cooperating gear drums are equal to the sound frequency ratios of the notes and half notes of an octave.

3. An electric music instrument as claimed in claim 1 in which the translucent portions of the opaquescreens are arranged in concentric rows of a number doubled from row to row. l a I 4. An electric music instrument as claimed in claim 1 in which the screens are identical and interchangeable.

5. An electrlc music instrument as claimed in claim 1 in which the motor is adapted to run at regulable speed. j

6. An electric music instrument as claimed in claim 1 in which means adapted to vary the ratio of revolutions of the motor and the series of gear drums are provided.

7. An electric music instrument comprising in combination electric current sources, a serles of contact springs continuously connected to one of the said current sources, bare reslstance means arranged opposite the said contact sprin s, key mechanisms adapted to make the sai contact roll onto the said resistance means, glow lamps connected to the said resistance means, photoelectric cells connected to another current source and arranged opposite to the said glow lam s, partlally translucent screens rotating etween the said glow lamps and the said photoelectric cells, and a telephone receiver connected with the said photoelectric cells.

8. An electric music instrument comprismg 1n combination a key board mechanism, an electric current source connected to the fixedparts of the said key board mechanism, a serles of contact springs rigidly connected ;at the one end to the said fixedparts and at .-the other end to the moving parts of the said 50' key board mechanism, bare resistance means arranged opposite the said contact springs and adapted to be touched by the said contact spr ngs, glow lamps connected to the said reslstance means, photoelectric cells connected to another current source and arranged opposite to the said glow lam s, partlally translucent screens rotating etween the said glow lamps and the said photoelectric cells, and a tele honereceiver connected with the said photoe ectric cells.

9. An electric music instrument comprising in combinationakeyboard frame having adjustable parts, an electric current source connected to the said adjustable parts, a series of contact springs individually connected std.

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the said ,adjustable parts, bare resistance means" arranged' o posite the said contact springs and adapts to be touched by the said contact springs, glow lamps connected to the said resistance means, photoelectric cells connected to'another current source and ar-' the-players side, levers fulcrumed on the said frame towards the layers side and adapted to be moved by t e said keys, a series of springs fixed at one end on the said levers, an electric current source connected to the said contact springs, bare resistance means arranged opposite the said contact springs and adapts to 'be touched by the same, glow lamps connected to the said resistance means, photoelectric cells connected to another current source and arranged opposite the said glow lamps, partially translucent screens rotating between the said glow lam s and the said photoelectric cells, and a te ephone receiver connected with the said photoelectric cells.

11. An electric music instrument comprising in combination akey board frame, longer and shorter keys fulcrumed 0n the said frame, levers arranged below and adapted to be actuated by the said keys,bolts arranged at the-lower sides of the said keys and adapted to touch the said levers at distances of the fulcrums of the said levers inversely proportionate to the length of the said longer and shorter keys, contact springs adapted to be actuated by the said levers, bare resistance means arranged o posite the said contact springs, an electric current source, glow lamps connected to the said current source and to the, said resistance means, hotoelectric cells arranged opposite the sai glow lamps, partially translucent screens adapted to rotate between the said glow lamps and the said photoelectric cells, a telephone receiver connected to the said photoelectric cells and a tele hone receiver connected with another current source connected to the said electric cells arranged opposite the said glow lamps, partially translucent screens adapted to rotate between the said glow lamps and the said photoelectric cells, a telephone receiver connected to the said photoelectric cells and another current source connected to the said telephone receiver and the said photoelectric cells.

13. An electric music instrument comprising in combination an electric current source, a key board mechanism, electric glow lamps connected to the said current source and adapted to be switched on and ofi by the said key board mechanism, a variable rheostat common to all said glow lamps, a pedal connected to the said rheostat and adapted to vary the resistance thereof, photoelectric cells arranged opposite the said glow lamps, partially translucent screens adapted to rotate between the said glow lamps and the said photoelectric cells, a telephone receiver and a current source connected to the said telephone receiver and the said photoelectric cells. I

14. An electric music instrument as claimed in claim 1 in which the translucent and opaque portions of the screens are formed by photographic sound records.

'15. An electric music instrument comprising in combination more than one key board mechanism, one set of glow lamps connected with each key board mechanism, one set of rotatable screens corresponding to each key board mechanism each of these sets bearing photograms of different timbres, a set'of photoelectric cells corresponding to each set of screens, a driving mechanism common to all the said sets of screens and a telephone receiver electrically connected to the said photoelectric cells.

In testimony whereof I affix my signature.

EMERIGH SPIELMANN.

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