US2539130A

US2539130A - Electrical musical instrument

Info

Publication number: US2539130A
Application number: US13028A
Authority: US
Inventors: Grudin Maurice
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-03-04
Filing date: 1948-03-04
Publication date: 1951-01-23
Anticipated expiration: 1968-01-23

Description

Jan. 23, 1951 M. GRUDIN 2,539,130

ELECTRICAL MUSICAL INSTRUMENT Filed March 4, 1948 4 Shee'tsSheet 1 BY W ATTORNEY.

Jan. 23, 1951 M. GRUDIN ,5

ELECTRICAL MUSICAL INSTRUMENT Filed March 4, 194a 4 SheetsSh eet 2 INVENTOR.

BY WW ATTORNEYS.

Jan. 23, 1951 M. GRUDIN ELECTRICAL MUSICAL INSTRUMENT 4 Sheets-Sheet 3 Filed March 4, 1948 I 1I!I!vrllltlvlllIIIIIIIIIIIIZIII iillll'lllt I I INVENTOR. Mfll/E/CE GKUD/N fioRN EYS.

OUTPUT C OMPEMJ'A T025 Red. Fans.

Jan. 23, 1951 GRUDlN 2,539,130

ELECTRICAL MUSICAL INSTRUMENT Filed March 4, 1948 4 Sheets-Sheet 4 ATTORNEYS.

l atenteci jan.

UNITED STATES PATENT OFFICE ELECTRICAL MUSICAL INSTRUMENT Maurice Grudin, Paterson, N. J. Application March 4, 1948, Serial No. 13,028

21 Claims. 1

This invention relates to playable electrical musical instruments, by the playing of which, musical compositions may be rendered by a musician, and wherein the sounds are produced by electrical phenomena, as distinguished from sounds produced by natural instruments, strings. pipes, reeds or the like.

In broad terms, the invention comprises a playing console, equipped with stops or slabs, and one or more keyboards controlling the initiation and termination of musical sounds. The sounds are produced by a loud speaker, and are derived by electromagnetic or electro-optical means from a plurality of sound tracks, tapes or wires, there being a separate track for each pitch and timbre within the scope and range of the instrument. The invention further includes arrangements by which tones of different pitch and timbre may be registered with each of the several playing keys of the instrument, so that each key of the instrument may be caused to produce the nominal pitch represented thereby, in any one of several timbres, and also to produce the pitches of tones one or more octaves away from the nominal pitch, again in any one of several timbres. The invention further provides for the production of a plurality of complex tones simultaneously, with each tone retaining its inherent fidelity and timbre characteristics.

A general object of the invention is to provide an organ-like instrument having a conventional console, the instrument being substantially selfcontained and semi-portable in character, wherein the key manuals, pedals and stops have both an arrangement and scope which Will enable a skilled organist to use the instrument Without special training or indoctrination. Thus, the playing technique of the instrument, being like that of the more or less conventional organ, enables the player to use the instrument inter changeably with a fixed type of organ. This playing interchangeability greatly facilitates both practice and training for ,organists. 'An other object is to provide an instrument whose scope is selectively unlimited, and to permit the use of any appropriate number of independent voices, including conventional organ voices and a large selection of orchestral instrument voices and special and unconventional voices, if the latter may be desired. A further object is to provide an instrument which keeps each produced tone, 'voice or timbre independent, so that whenvarious voices and tones are used coincidentally, each retains its own timbre with complete fidelity, as does a full organ or orchestra. Another object of the invention is to provide selective registry of different voices and their pitches on the keyboard, and to provide for selective registration or production of several voices and pitches thereof by depression of a single key of a manual. A further object is to provide for the selective registration of one or more voices and pitches on several keyboards, one of which may comprise pedals.

Another object is to provide an instrument in whichtones of desired timbre and pitch are pro-'- duced electrically, either by photoelectric or magnetized wire or tape means, the electrical impulses derived from such means being amplified, and converted to sound by a loudspeaker or the like. Preferably, the instrument is unitary in construction, the speaker unit being embodied in the instrument, or being separate therefrom as desired.

A further object of the invention is to provide means for producing sound track or sound wire or tape elements from a single tone of desired timbre to embrace a pitch range appropriate to the timbre, for use in the electrical musical instrument.

It is known that various playable electrical musical instruments have been proposed wherein the tones are synthesized from their funda-- mentals and harmonics, to produce any timbre desired, either of a conventional instrument, or of an unusual quality which may not ordinarily be found in a natural instrument. However, such instruments have serious limitations when chords are played or when several octave pitches are registered by the same key, for the fidelity of component tones of chords is sacrificed due to the coincidence of synthesized frequencies in several tones of the chord and the consequent aberration of the timbre desired. The harmonics of one tone may coincide with fundamentals or harmonics of another, whereby the timbre of both is materially modified. Only by compromising the true timbre of tones may pleasing chordal efiects be produced, and these are only tolerable by virtue of the courtesy or insensitivity of the player or listener.

Further objects of the invention will become apparent in reading the annexed detailed description in connection with the drawings, which show the essential provisions of the invention in one or more preferred forms. These forms are, however, exemplary, and are not to be construed as limiting the scope of the invention.

In the drawings, in which similar reference numbers indicate similar parts, and in which certain symbols are used for assisting understanding of the invention;

Fig. 1 is a schematic diagram of a portion of a keyboard of one embodiment of the instrument and associated registry and sound actuating circuits;

Fig. 2 is a front elevation of an entire instrument showing the general disposition of the components therein;

Fig. 3 is an end elevation of-th-e entire'instrument;

Fig. 4 is a partial schematic diagram of a modification or addition to the instrument to produce fundamental and harmonic tones;

Fig. 5 is a side sectional elevation of one of the sound track units;

Fig. 6 is an end sectional elevation of the sound track unit of Fig. 5;

Fig. 7 is a general wiring scheme of one embodiment of the instrument;

Fig. 8 is an end elevation of a soundtrack unit utilizing electromagnetic pickups;

Fig. 9 is a planof a portion of the unit shown in Fig. 8;

Fig. 10 is an enlarged end elevation, partly in section, of one of the pickup units of Fig. 8;

Fig. 11 is a schematic wiring diagram of the circuit system utilized with the pickups of Fig. 8;

Fig. 12 is an enlarged end elevation partly in section of an'alt-ernative electromagnetic pickup unit;

Fig. 13 is a schematic wiring diagram of a circuit system utilized with the pickup of Fig. 12; and

Fig. 14 is a schematic arrangement of a sound ,transposing machine.

Referring briefly to Figs. 2 and 3, I show an entire instrument in the form of ,an organ console Ill, including a plurality of key manuals 12, a panel for stops or slabs l4, pedals l5, and swell pedal 16. The console contains a plurality of demountable box units [8 each comprising a voice, such as flute, string, oboe, horn, diapason, etc., all driven if desired by a common motor 20. The voices may be of any desired number, eight being shown as a number suitable, for average needs, to produce musical effects over a wide range. The voice boxes may be inserted into the ends of the console, leaving the middle part free for incorporating junction panels, amplifiers, speakers, and necessary auxiliaries which will be described.

Now referring to Fig. l, I show a key manual portion l2, embracing 5 octaves, wherein the keys are identified by their pitch symbols C0, C1, C2, etc., some of the intervening keys of each octave being similarly symbolized. Each key operates a S. P. S. T. switch 2| which is connected to a contact 22 bearing the key symbol, on a main contact panel 2 1. This panel includes a plurality of horizontally shown contact rows, each row comprising contacts for all keys of the keyboard; all contacts on vertical lines are inter-connected with each other and with the key switches for the keys having the same key symbols.

Into all contacts of the first contact row 26 may be plugged a bar 28 carrying contacts 30, each engaged with one of the contacts 22, the several contacts 30 being connected by conductors 32 to the points 33 of one member of a multi-- point stop switch 34, actuated by a stop button or slab constituting one slab of the panel M (Fig. 2). The other member of the stop switch 34 carries a plurality of points 35, respectively connectible or disconnectible relative to the f rst set of points 33 by operation of the stop. Conductors lead individually from each point of the set 35 to each of a series of solenoid units 38, said solenoid units being operable to open and close a sound track to a pickup as will be described. The stop 34 when operative, gives nominal registry of the keys with the solenoid units 38, so that, for instance, depression of key 03 produces the pitch C3 by operation of the solenoid unit 38 corresponding to pitch C3 of the voice represented by the stop 3 This yields 8 foot pitch registry. In addition to nominal key registry, it is highly desirable to use, at times, registries of one or more octaves higher or lower than nominal, to give richness of tone and additional volume, and also to register high or low tones on the manuals for convenience in playing the instrument. Also, different voices in different parts of the tonal range may be played simultaneously by single keys. Provision is made for different registries in the manner described below.

A contact bar 43 is plugged into the row of contacts 42, on the panel 24, the contacts 44 of the bar being connected to fixed contacts 46 of a stop switch 48. Movable contacts 50 of the stop switch are connected ,to separate windings incorporated in the solenoid units 38, but in an order such that, when the stop switch 48 is closed, depression of key C3 operates the solenoid unit corresponding to pitch C2, and depression of any other key will actuate the solenoid unit corresponding to a pitch one octave lower than the nominal key pitch. This yields 16 foot pitch registry.

A contact bar 54, plugged into a row of contacts 56 on the panel 24, connects said contacts to a stop switch 58, which in turn connects to solenoid units 38 in an order such that, when the stop 58 is operative, depression of key C3 operates the solenoid unit correspondin to pitch C4, and depression of any other key actuates a solenoid unit corresponding to a pitch one octave higher than the nominal key pitch. This yields a foot pitch registry.

In the same manner, registries of 32 foot pitch and 2 foot pitc h-that is, two octaves lower or two octaves higher than nominal, may be secured by providing additional contact bars and stops.

The same contact panel 24 may be utilized, in conjunction with additional stop switches such as 60, to connect othersets of solenoid units 38a to the keyboard, such other solenoid units being associated with other voices of the instrument. Ofiset tone registries may also be effected in the manner described to secure fifths, seventeenths, or any other desired interval from the nominal tone. That is, the playing of key C1, for instance, may -prcduce tone G1 (for the fifth) or E3 (for the seventeenth) with corresponding intervals for other keys. Furthermore, registries may be changed at the discretion of the organist, by lifting out a bar, such as bar 28, from its contacts 26, and reinserting it into the row of contacts 26 in such relation as to shift the coincidence of contacts 39 and 26 from the original registry to an octave higher or lower, or oifset for fifths, seventeenths, nineteenths or any other desired interval.

The contact panel 24 is associated with a single keyboard or manual l2. If additional manuals or pedals are used, each has a panel, like 24, to enable a plurality of connections to be made to the available voices of the instrument. In this connection, the solenoid units such as 38 may not only be connected to one manual through several stop switches to secure different octave registries, but may also connect to one or more additional manuals or pedals, either for single or multiple octave registry with each,

From the preceding description, it is apparent that stops 58, 48, 34 may be actuated individually or jointly, to secure desired octave registrations on the one manual shown.

In Fig. 4, I show a connection arrangement for onevoice of the instrument to provide a plurality of pure tone qualities over the pitch range desired, such tones being produced from sound tracks of pure sine wave character without the overtones which characterize usual organ or'instrumental timbres. These pure tones are, at times, very useful, either to synthesize tones-of unusual quality, to play by themselves, or to fortify and augment tones of complex composition by superimposition thereon. The Fig, l ar rangement is shown for exemplary purposes-for two pitches A1 and A2 and enables the combination of any one or all of the first six harmonics of the fundamental pitches. In practice, the connections are carried out for all semitone pitches of the range desired. The manual keys as previously described operate key switches 2| connected to the panel 24. Several horizontal rows of contacts in the panel are reserved for liar-- monic connector bars whose plugs are respectively connected to stop switches respectively designated HI H2, H3, H4, H5 and H6. These stop switches, when in the active position respectively set up the solenoid units of the first to sixth harmonics. The harmonics of the fundamental or first harmonic pitches A1 and A2 correspond with other fundamentals in the tempered scale as shown in the tabulation below, and the connections from the harmonic stop switches HI to H6 are made to the solenoid units corresponding to such other fundamentals, as shown. As previously described, the solenoid units have a separate winding associated with the appropriate sound track for each connection from a stop switch, to avoid shadow circuits and cross-talk.

I am aware that in order to produce timbres solely by synthesis of partials or harmonics it is more desirable to have available more than six harmonics in more than one degree of intensity. However, I have found that for a practical instrument of the type herein described, the use of the first six partials in but one degree of intensity offers by synthesis and by alteration of stock stops a more than sufiicient number of timbres for the production of usable and highly desirable musical effects. The addition of harmonies opens up a vast field of tone colors, inasmuch as these harmonics in their numerous combinations create new timbres, and the addition of one or more harmonics to a stock stop or combination of stops produces a still greater number of new timbres. Thus, (1) the admixture of 6 harmonics alone, (2) the addition of one or more harmonics to an individual stop or combination of stops, (3) the use of one or more independent stops, make available to the player a number of timbres which may well nigh be described as limitless.

Referring now to Figs. 5 and 6, details of a typical voice unit l8 are shown, in conjunction with a series of associated solenoid units 38. In one arrangement of the invention, each voice unit l8 comprises a cylindrical transparent drum 62 secured for rotation in end bearings 64, and driven at constant speed through a transmission 66 by a motor 68. Within each drum is a light source I8, and suitable provisions may be made for ventilating and cooling the unit by circulating air through the drum. Around the drum are secured a plurality of axially spaced sound tracks 12, there being one such track for each pitch over the range desired, all tracks preferably representing tones of the same timbre. These sound tracks may represent an organ timbre, an orchestral instrument timbre, or any other, including the fundamentals and harmonics indigenous to each. There need be no particular phase relationship between the waves of each track, and each track produces its own monotonef of full fidelity and timbre. I have found little or no need for matching wave patterns at the ends of each track at it is wrapped around and secured to the drum, as the interruption caused by mismatched wave patterns, at the one point in the drum circumference, where the track ends meet, is so minute as not to be noticeable even to the most critical ear.

Around the drum 62 is disposed a light shield 14 having a longitudinal narrow slit 16 therealong, or a plurality of holes one opposite each track. Either above or below the shield 14 may be disposed a plurality of individual tapered light filters 18, one for each track, to enable adjustment of the sound level produced by each track.- Either another long tapered filter may,

be introduced to adjust the sound level of the entire unit, or the filters 18 could be adjustable jointly, as well as individually, to attain the same result. Spaced beyond the slit and filter is a shutter 88 for each track 12, the shutter normally masking the slit and being movable to uncover the slit by the associated solenoid unit 38 of which the shutter is a part. Beyond the shutters are a plurality of lenses 82 for focusing the beams from open sound tracks onto one of a set of interconnected photocells 84. These receive light signals from the lamp (0 within the drum as modulated by the sound track 12.

Photocell output is conducted to an amplifier 88 (Fig. 7), and amplifier output controlled as to overall sound level by the swell pedal I6, is transmitted to a speaker 90.

Accordingly as one or more shutters 8!! are operated, one or more true individual tones are produced in the speaker,,blending to produce harmonious music without distortion or aberration.

The solenoid units 38 (Fig.5) each comprise a plurality of solenoid windings 92, and an armature 94, carrying the shutter 80, which is operable by the energization of any one winding 92. One end of each winding 92 connects to a common ground, while the other end connects to one contact of one of the stop switches such as 34, 48 and 58 (Fig. 1). This arrangement of multiple solenoids in each unit 38 has been found to give excellent results, and to avoid any possiassarso' bility of shadow circuits or cross-talk between different stops, keys, and voice units. Other interconnecting arrangements. are no doubt feasible, and I do not necessarily wish to confine the scope of the invention to the connection systion shown. In the solenoid units 38, windings from one to seven or more may be employed. If but a single tone registry on a single manual is needed, the single winding is adequate. Seven windings are desirable when the tone is to be producible in one registry on the pedals and in three registries (4', 8 and I 6') on each of two manuals.

As noted in Fig. '7, a common power supply may energize the amplifier 80, motor 58 and key system, the latter preferably operating at low D. C. voltage through a transformer 90 and a rectifier Bl.

It is contemplated that selective tremolo .effects may be produced by periodically raising and lowering the overall sound frequencies. There are known methods for producing the tremolo, such as by varying the speed of the motor 08 at cyclic intervals of 5 to 9 per second. Another arrangement is to insert a selectively operable cyclically varying drive between the motor 60 and the drums 52.

An alternative sound track system is shown in Figs. 8 to 13, wherein an insulating or nonmagnetic drum I64 is driven, as before, by the motor 08 and transmission 68. Preferably, the peripheral speed of the drum is of the order of 120 to 250 feet per minute to attain high fidelity sound production. Around the drum are secured a plurality of magnetic wires or tapes I06, one for each tone over the range desired, each Wire or tape being magnetized to produce, when associated with a pickup and speaker system, a tone of desired pitch and timbre. The several wires or tapes provide the desired range of pitch. The wires or tapes are spaced apart to avoid cross-talk, and with each wire or tape is associated one or more magnetic pickups I08 which are analogous in function to the solenoid units 38 of the electro-optical system previously described. The pickup comprises pole pieces I01 having a winding Hi9, whose ends lead to an amplifier and speaker system.

The Wire-carrying drum I04 is rotated in bearings I I0, and at each end of the drum is a spider H2 having a plurality of spoke-like arms; Ht across the ends of which are secured members H6 upon which the pickups I08 are mounted. The spiders IE2 are selectively oscillatable about the center of the drum, at a frequency of between 5 to 9 cycles per second, while the drum is rotating at constant speed, to attain tremulant effects. Such oscillation may be attained by a small motor I I8 having a crank I I 9 connected to one end of a spider arm I I4 by a connectin rod I20. When the drum oscillates the frequency of impulses picked up by the devices I08 varies slightly and cyclically, to yield the tremolo.

Referring to Figs. 10 and 11, based on the general arrangement of Figs. 8 and 9, I show one arrangement and circuit system for using the magnetic pickups. The pickup I00 is mounted on a bar I22 pivoted at I26 to one of the members I IS. A light spring I26 holds the bar I22 in place, and urges the poles of the pickup Ida into light, continuous engagement with the magnetized sound wire I06. The pickup pole pieces and the Wire are preferably highly polished to minimize wear and distortion of the impulses picked up from the Wire (or tape). Fig. 11 shows a fragmentary typical circuit diagram, wherein two keys and two pickups are showns. It will be apparent that an entire key system will be arranged in generally the same fashion. Each pickup coil I09 connects to a transformer primary I26 at all times, the two primaries being related to a joint secondary I28. The secondary provides the input to the amplifier 88 and speaker 90. One end of each pick.- up is, groundedthe other end of each leadingto center points I30 of a stop switch I32. When the stop switch is off or up, as shown, the pickups are short-circuited through ground as at I34 whereby they do not transfer energy to the trans.- former I26-I28. When the stop switch is on, the pickup coil ends are connected to points. I35, through the junction panel 24 of normally closed grounded key switches I38. When the key .isat rest, the pickup coil I09 is ground-shorted, but when the key is pressed, the short is broken'and the pickup coil I09 ,feeds energy to the transformer and sound system.

In an alternative system shown in Figs. 1 2 and;

her I I6, serves when energized to move the pick-,

up into contact or pickup relationship to the wire I06, the arm M0 having secured thereto an armature I48 entering the solenoid. Cushioning means, such as felt, is provided to prevent bouncing of the pickup on the wire when the solenoid is energized, and additional cushioning means may be applied to prevent pickup bounce when it is disengaged from the wire. The solenoids I06 operate in the same kind of key system as is shown in Fig. 1, and are comparable to the solenoid units 38. The key switches 2|, junction panel 24, and stop switches are similar. In this arrangement the pickup coils I09 are constantly connected to their respective transformer pri.-. maries I26, but the solenoid circuits are normally open.

To enable relativel close spacing of wires I06 on the drum I04, and to provide for an adequate number of pickups I08, the latter may be spaced circumferentially around the drum as shown in Figs. 8 and 9. By this arrangement a plurality of pickups may be associated with each wire I06, each pickup being connected to one of the several stop switches to enable playing of a single tone from a plurality of manuals, pedals and key positions. The pattern for the multiple playing of a single note follows, in general, the same principles as were outlined heretofore in connection with the sound-track optical system.

The magnetized wire system shown may yield augmented musical effects, since a specific pitch and timbre may be produced by several pickups each operated by a different key, the sound pro,- duced by each key depression being additive to the similar sounds produced by other key depressions. This has the same effect as though there were duplicated, triplicated or multiplied voices in the organ system. This is desirable but usually impractical in the natural organ or electrical organ analogue.

In the foregoing description I have used the terms solenoid, and solenoid units, to designate,-

mane to the invention herein disclosed, there bee I ing many desirable mechanical arrangements ofparts .to fulfill the function required. I find that the generalarrangements shown minimize the possibility of key click in the speaker system of the instrument, since the pickups or photocells are always connected during playing, and are rendered active by optical or mechanical connection to the sound tracks or wires. Were the photocell or pickup circuits to be made and broken each time a note is played, obnoxious key click would be almost inevitable.

Further, in either the optical or magnetic pickup systems described tones are initiated or terminated smoothly, without obiectionable suddenness. If desired, the speed of tone initiation and termination may be varied by varying the response speeds of the solenoid units. In the mag-' netic wire systems, I prefer to use a sequence of wires on each drum which will minimize the possibility of discordant cross-talkthat is, pickup of dissonant frequencies by a pickup unit from wires which are neighbors of the wire with which the unit is directly associated. To this end, all of the C pitch wires are neighbors, and comprise the first group.. The next group comprises all the G pitch wires, then in sequence, groups of D, A, E, B, Ft, Ct, Gt, DII, AII, F are arranged. The intervals between all groups are fifths, and the intervals between wires in a group, octaves, so that any cross-talk which may occur will always be harmonious.

The sound wire on the drums (tape being considered equivalent to wire) may be wound as a plurality of separate spaced turns, or the wire may be wound continuouslyto form a multi-turn helix. In the latter form, the helix turns may be offset sharply from one turn to the next to enable each wire to run predominantly centrally under its pickups. The magnetization of the wires to represent appropriate pitches and timbres may be accomplished before or after the wire is placed upon the drum.

It will be noted that in the optical system, a single light gate may be operated by any one of several solenoids associated therewith to. secure pickup from a single sound track, while in the electromagnetic system, a separate pickup is preferred for each key and stop combination with the result that there are several pickups associated with each sound wire. The wire or tape system comprehends their assembly as voice units such as I6, as previously described in connection with the optical system, all voices being energized by the same drive motor, and all sound bein reproduced by the same amplifier and speaker, with coincidental volume regulation by the swell pedal I6.

For the purpose of securing true pitch sound tracks either as translucent tracks for use with the electro-optical system of reproduction or withthe electromagnetic tape "or wire system, I hav evolved a mechanism which may produce an entire range of pitches of certain timbre from a recording of asingle pitch of the desired timbre. This mechanism is shown in Fig. 14. It comprises a turntable I60 borne in a housing I62 by a shaft I64, the shaft having a bevel gear I66 meshed with a bevel gear I68 whose shaft I is also borne in the housing. The shaft carries a wheel I12 faced with friction material, the wheel being engageable with any one-of a plurality of pulley faces on a stepped pulley I14. 1 The housing I62 is mounted for tilt and sliding on a horizontal rod I16 carried by brackets I I8, so that the housing, with its turntable and drive mechanism, may be shifted along the pulley 14. The brackets I18 and the shaft I-16are-spaced-fr0m the pulley I14, lying behind the pulley and the axis of the turntable I84. Thereby, the entire housing I62 may be tilted up and down on the shaft I16 as it is slid therealong, to allow engagement of the friction wheel I12 with any one of the steps on the pulley. The weight of the housing and its associated parts is sufficient to load the wheelIIZ into firm frictional driving engagement with the pulley I14.

The pulley I74 is driven through a changespeed gearset I from a constant speed motor I82, successive ratios of the gearset having2z1 relationship. That is, the pulley I "I4 may be driven at, say, a minimum speed of 25 R. P. M. Successive ratio steps would be 50, 100, 200, 400 and 800. The 13 steps of the pulleyincrease progressively in diameter by the ratio 1.05946 driving the turntable at similar R. P. M. ratio increments. For example if the smallest pulley face is .500 inch in diameter successive faces will have diameters .5297, .5612, .5946, .6299, .6674, .7071, .7492, .7937, .8409, .-8909, .9439, and (13) 1.0000. If a monotone record I84 of desired timbre is placed on the turntable, and the pickup I86 is connected to a suitable reproducer, any desired range of all notes of several octaves of the tem-.- pered scale may be reproduced by changing the driven speed ofv the turntable, by shifting the wheel on the step pulley I14 for semitone intervals Within an octave, and by shifting the gearset I80 for octave intervals. The output of the pickup I86 is connected to known apparatus to produce optical sound tracks (12 in Fig. 6) or magnetized sound wires or tapes (I06 in Figs. 8- 12). Such tracks may be produced for use on the drums forming parts of the voice units I8 of Figs. 2 and 3. Any appropriate tone timbre may be secured by the use of appropriate monotone records I84.

Though several embodiments illustrating the invention have been shown and described, it is to be understood that the invention may be applied in other and various forms. Changes may be made in the arrangements, without departing from the spirit, of the invention. Reference should be had to the appended claims for definitions of the limits of the invention.

What is claimed is:

1. In an electrical musical instrument, a plurality of sound tracks having the same and complex timbre and dififerent pitch, at least one pickup energizable by the tracks, a sound producer responsive to pickup energization, means to translate the tracks relative to the pickup, selectively operable means associated with each track to place the track in energizing relationship to the pickup and to place the track in inoperative relation to the pickup, a keyboard, a key switch for each key of the keyboard, and means to connect eachkey switch to one and more of said selectively operable means, whereby key switch operation may plac one and more tracks of the same timbre but of different pitch in operative relation with said pickup.

2. In an electrical musical instrument, a plurality of sound tracks having the same and complex timbre and different. pitch, at least one pickup energizable by the tracks, a sound pro-1 ducer responsive topickup energization, means to translate the tracks relative to the pickup, selectively operable means associated withseach track to, ace the track in energizing relation and to place the track in inoperato the pickup, a keyboard, a key switch-foreachkey of thekeyboard, meansto.

connect each key switch to one and more of said selectively operable means, whereby key switch operation may place one and more tracks of the same timbre but of different pitch in operative relation with said pickup, said sound tracks comprising filaments magnetized in accordance with pitch and timbre of the tone to be produced, and said pickup comprising means magnetically engageable with said filament and producing electrical impulses in conformance with the magnetization of said filament.

3. An electrical musical instrument compris ing a plurality of selectively operable key switches each closable toproduce a nominal tone, a plurality of multi-point stop switches each including two sets of points, connections from said key switches to respective points of one set of each of said stop switches, a plurality of actuators, connections from said other sets of stop switch points to said actuators in a plurality of combinations, a full-timbred sound track operatively associated with each actuator, and sound produc ing means responsive to enargization of said actuators individually and in groups to produce the same ful1-timbred sound corresponding to the one or more tracks brought into operation by onergization of respective actuators.

4. An electrical musical instrument comprising a plurality of selectively operable key switches each closable to produce a nominal tone, a plurality of multi-point stop switches each including' two sets of points, connections from said key switches to respective points of one set of each of saidstop switches, a plurality of actuators, connections from said other sets of stop switch points to said actuators in a plurality of combinations, a full-timbred sound track operatively associated with each actuator, and sound producing means responsiv to energization of said actuators individually and in groups to produce the same character of full-timbred sound corresponding to the one or more tracks brought into operation by energization of respective actuators, said actuators comprising electro-magnetically operated devices operable to render said tracks activeand inactive.

5. An electrical musical instrument compris ing a plurality of selectively operable key switches each closable to produce a nominal tone, a plurality of multi-point stop switches each including two sets of points, connections from said key switches to respectivepoints of one set of each ofsaid stop switches, a. plurality of magnetic pickups, actuating means to render said pickups acthe connections from said other sets of stop switch points to said actuating means in a plurality of combinations, a full-timbred sound track operatively associated with each pickup, and sound producing means responsive to energization of'said' pickups individually and in groups to produce the same character of full-timbred sound corresponding to the one or more tracks brought into operation by energization of respective actuators, said actuators comprising electro-magnetically operated devices operable to render said tracks active and inactive relativeto their pickups, and said tracks comprising, magnetized filaments.

6. In an electrical musical instrument, a light modulating sound. track, a light source, a photocell responsive'to light from, the source as modulated' by the track, a light shutter in the path of light from said. source tosaid photocell selectively operable to pass and not to pass said light, said shutter comprising a movable; shutter else:

I2 ment, a plurality of solenoids individually and, jointly energizable to move said shutter, a plurality of playing key switches connected with and selectively closable to energize respective: shutter solenoids, and stop switching means, selectively operable, and interposed in the connections from said key switches to said shutter solenoids.

'7. In an electrical musical instrument, a plurality of signal producing units each comprising a series of tracks having characteristics of Sim-- ilar complex timbre over a certain pitch range, a sound producer responsive tothe signals of the several producing units, a plurality of playingkey switches, and means selectively operable to con-' nect each key switch to one and more of said producing units simultaneously, in octave intervals, to produce sound signals from said tracks and sound producer upon key switch closure.

8. In an electrical musical instrument, a plurality of signal producing units each comprising a series of tracks having characteristics of similar complex timbre over a certain, pitch range, a sound producer responsive to the signals of the several producing units, a plurality of playingkey switches, and means selectively operable to con,- nect each key switch to one and more of said producing units simultaneously in octave intervals, to produce sound signals from, said tracks and sound producer upon key switch closure, said selectively operable means'including connections to afford a plurality ofv octave registries of" said key switches with the sound tracks. of said units.

9. For use in preparing a plurality of sound tracks of similar timbre for an electrical musical, instrument, a turntable for a record of a monotone of desired timbre, a record pickup, sound track recording means'responsive to said pickup, a drive shaft, and a transmission from said drive shaft to said turntable comprising a stepped drum having a plurality of steps having a diameter increment ratio of substantially 1.65946 driven by said drive shaft, a follower wheel selectively engageable with the drum steps,

and means for driving the turntable fromv the follower wheel.

10. For use in preparing aplurality of sound tracks of similar timbre for an electrical musical instrument, a turntable for a record of a monotone of desired timbre, a record pickup, sound track recording means responsive to said pickup, a drive shaft, a transmission from said drive shaft to said turntable comprising a stepped drum having a plurality of steps having a diameter increment ratio of substantially 1.05946 driven by said drive shaft, a follower wheel selectively engageable with the drum steps, means for driving the turntable from the follower wheel, and means for changing the speed of said drive shaft in the ratio 2:1.

11. For use in preparing a plurality of sound tracks of similar timbre and difierent pitch, for an electrical musical instrument, a record of monotone pitch and desired timbre, pickup means for. saidrecord, meansto re-record sound tracks v stantially 1.05946 between steps of increasing diameter, said wheel and drum comprising input and output members, notnecessarily respectively, means to drive-said input member at constant 13 speed, and means to drive said single pitch record from said output member.

12. In an electrical musical instrument, a plurality of playing keys each including a switch, a plurality of full-timbred voice units, each unit having a range of full-timbred tones of the same voice, a contact panel having a plurality of lines of contacts, means connecting each line with a key switch, each voice unit having a plurality of control conductors each representing one note of its voice unit, and means operable to connect the said control conductors from one voice unit simultaneously and in tonal sequence, to the lines of contacts of said panel.

13. In an electrical musical instrument, a plurality of playing keys each including a switch, a

' plurality of full-timbred voice units, each unit having a range of full-timbred tones of the same voice, a contact panel having a plurality of lines of contacts, means connecting each line with a key switch, each voice unit having a plurality of control conductors each representing one note of its voice unit, means operable to connect the said control conductors from one voice unit simultaneously and in tonal sequence to the lines of con-.

tacts of said panel and means to shift said control conductors as a unit to cause registries of said conductors, in tonal sequence, with different lines of contacts of said panel.

14. In an electrical musical instrument, a plurality of playing keys each including a switch, a plurality of full-timbred voice units, each unit having a range of full-timbred tones of the same voice, a contact panel having a plurality of lines of contacts, means connecting each line with a key switch, each voice unit having a plurality of control conductors each representing one note of its voice unit, means operable to connect the said control conductors from one voice unit simultaneously and in tonal sequence, to the lines of contacts of said panel and means to shift said control conductors as a unit to cause registries of said conductors, in tonal sequence, with different lines of contacts of said panel whereby at a players option, registry of a C1 key, for example, may be effected with a C0, C1 and C2 tone of any one of said voice units.

15. In an electrical musical instrument, a plurality of playing key switches, a connection panel having a plurality of contact elements rectilinearly disposed in lines and rows, the elements in each line being interconnected and connected to one of said key switcheaa plurality of bars each having a plurality of contact elements engaged with the panel contact elements of one row, said bars being interchangeable between rows and being adjustably shiftable along a row, a plurality of sound signal generating units, one for each bar, each having a range of musical tone signals and each having conductors, one for each tone, energizable to produce respective signals, selectively operable multiple contact stop switch units, the conductors of said generating units being connected in order to the respective contactsof said stop switch units, and means connecting other contacts of said stop switch units, respectively, to the contact elements of said several bars.

16. In an electrical musical instrument, a plurality of playing key switches, a connection panel having a plurality of contact elements rectilinearly disposed in lines and rows, the elements in each line being interconnected and connected to one of said key switches, a plurality of'bars each having a plurality of contact elements engaged the panel contact elements of one row, said 14 barsbeing interchangeable between rows and being adjustably shiftable along a row, a plurality of sound signal generating units, one for each bar, each having a range of musical tone signals and each having conductors, one for each tone,

energizable to produce respective signals, selectively operable multiple contact stop switch units, the conductors of said generating units being connected in order to the respective contacts of said stop switch units, and means connecting other contacts ,of said stop switch units, respectively, to the contact elements of said several bars, said bars and generatingunits being replaceable, and said bars being position-shiftable along the rows of said panel to alter the key registration relative to the nominal tones available from said generating units.

17. In an electrical musical instrument, a plurality of playing key switches, a connection panel having a plurality of contact elements rectilinearly disposed in lines and rows, the elements in each line being interconnected and connected to one of said key switches, a plurality of bars each having a plurality of contact elements engaged with the panel contact elements of one row, said bars being interchangeable between rows and being adjustably shiftable along a row, a plurality of sound signal generating units, one for each bar, each having a range of musical tone signals and each having conductors, one for each tone, energizable to produce respective signals, selectively operable multiple contact stop switch units, the

conductors of said generating units being connected in order to the respective contacts of said stop switch units, and means connecting other contacts of said stop switch units, respectively, to the contact elements of said several bars, said generating units each having a single musical timbre for the range of tones producible thereby.

18. In an electrical musical instrument, a plurality of playing key switches, a connection panel having a plurality of contact elements rectilinearly disposed in lines and rows, the elements in each line being interconnected and connected to one of said key switches, a plurality of bars each having a plurality of contact elements engaged with the panel contact elements of one row, said bars being interchangeable between rows and being adjustably shiftable along a row, a plurality of sound signal generating units, one for each bar, each having a range of musical tone signals and each having conductors, one for each tone, energizable to produce respective signals, selectively operable multiple contact stop switch units, the

conductors of said generating units being connected in order to the respective contacts of said stop switch units, and means connecting other contacts of said stop switch units, respectively, to the contact elements of sa d several bars, said stop switch units being of a number corresponding to more than the number of generating units, and being connected for different registries of said key switches with the tones of said several generating units as well as for nominal registry.

19. In an electrical musical instrument comprising a selectively operable keyboard, a pickup, and a speaker energized by said pick-up, a movable sound track-carrying member having a plurality of tracks thereon, said pickup being associated operably with said tracks, means responsive to key operation to energize said pickup for signal production resulting from key operation, said plurality of tracks being arranged in a sequence of groups, each group containing tracks having 15 octave. intervals therebetween, and said groups having fifth'intervalstherebetween.

20. In an electrical musical instrument comprising-a selectively operable. keyboard, a pickup, and a speaker energized by said pickup, a movable sound track-carrying member having a plurality of tracks thereon, said pickup being associated operably with said tracks, means responsive to key operation to energize said pickup forxsignal production resulting from key operation, there being} fifth intervals between certain individual adjacenttracks of said plurality.

21. In an electrical musical instrument comprising a selectively operable keyboard, a pickup,

a speaker energized by said pickup, a movable sound track-carrying member having a plurality of tracks thereon, said pickup being associated opera-bly with said tracks, means responsive tokey operation to energizesaid pickup for sig- 16 nal production resulting from key operation, there being octave intervals between certain in dividual adjacent tracks of said plurality.

' MAURICE GRUDIN.

REFERENCES CITED The following references are of record: in the file of this patent:

UNITED STATES PATENTS Number Name Date 978,722 Fajen e Dec, 13,1910 1,218,824 Severy Mar. 6,1917 1,848,222 Potter i Mar. 8, 1932 1,941,870 Severy Jan.. 2, 1934 1,956,350 Hammond Apr. 24, 1934 2,164,809 Fisher July 4, 1939' 2,169,842 Kannenberg Aug. 15,1939 2,484,881

SuSChi Oct. 18,, 19.49.