US1705395A - Synthetic tone musical instrument - Google Patents

Description

March 12, 1929. 5, CABQT SYNTHETIC TONE MUSICAL INSTRUMENT Filed July 5, 1918 5 Sheets-Sheet jut/Qtior SwasZZ @505 March 12, 1929. S..CABOT SYNTHETIC TONE MUSTCAL INSTRUMENT Filed July 5, 1918 v 3 Sheets-Sheet ve7zz o7 e waZZ @505 KZI I v WOT'TC/Qy March 12, 1929.- s. CABOT SYNTHETIC TONE MUSICAL INSTRUMENT Filed July 5, 1918 3 Sheets-Sheet @OKZ/ I l l l J ZZZ/876567) Sea/Q55 6 Waltz/v W IPIRW U EFSZ Patented Mar. 12, 1929.

UNITED STATES SElVALL CABOT, OF BROOKLINE, MASSACHUSETTS.

SYNTHETIC TONE MUSICAL INSTRUMENT.

Application filed July 3,

This invention relates to musical instruments of the type in which a separate sounder is provided for each tone or pitch of the scale, so that the sounders may be brought into play separately or in any desired combination,

and sustained for any lengthof time, according to the score, the will of the performer in the case of manual playing, or according to the recorded interpretation in a perforated sheet or otherplaying agent of an automatically operated mechanism.

Une object of my present invention is to provide an improved musical instrument of relatively small cost and small dimensions in comparison to those of a pipe-organ, but capable of attaining all the musically useful results of which a pipe-organ is capable. Another object is to provide an instrument that will produce desirable tonal effects not heretofore obtainable from a pipe-organ.

The pipe organ, which is the best known example of an instrument for producing music of various qualities, is complex, expensive, and occupies great space, for the reason that it requires a distinct set of sounders for each quality of tone provided.

The extreme multiplicity of sounders'has been reduced in some degree by the electromagnetic instrument known as the Choralcelo, and disclosed in some degree of perfection by U. S. Letters Patent 1,098,983.

It has been proposed (see U. S. Letters Patent 1,110,012 and 1,181,486) to utilize the natural harmonics in strings vibrated with frequencies that are multiples of the frequency of the fundamental pitch to which the strings were tuned, to obtain a change in tone quality, but the net result did not produce sufiicient volume or contrast to compete favorably with those of a pipe organ.

More specifically, an object of the invention is to provide a musical instrument with which synthetic tones are produced by compounding the waves generated by harmonically related sounders each vibrated at its normal or fundamentalfrequency.

A feature of the invention consists in means for bringing into play, each at its normal frequency of vibration, two or more sounders simultaneously by the action of aprimary controller. which, in the case of a manually played instrument, would be a key or pedal. I prefer sounders that execute simple harmonic motion in the pitches of the equally tempered scale. The sounders so brought into play are related to each other 1918.- Serial No. 243,239.

in pitch just like so many partials of a compound tone appertaining to the primary controller. Thus, with .one possible combination, a primary controller may bring into play, not only the sounder having the pitch appertaining thereto, but those correspond ing in pitch to the second and third partials of a compound tone of that pitch. Each sounder, therefore, would contribute its simple harmonic motion of predetermined regulatable amplitude to the production of a synthetic tone.

Another feature consists in controlling and varying the relative intensities of the sounders played conjointly as aforesaid, to the end that each fundamental and each harmonic will have the requisite force, but no more, to produce the tonal eifect desired.

.Thus, by varying the number and the harmonic relation of the combined sounders, and by varying the relative forces with which they are played, a great variety of tone qualities may be produced. The invention is not limited to any number or to'any one harmonic relation of sounders played conjointly, nor to any relative force with which they are played, but I have found that when provision is made for combining five or any less number of sounders, each with four different relative forces, it is possible to approximate very closely the tone qualities of all the well known musical instruments, and to produce many new tone qualities that are musically useful.

Preferably, and as shown. the sounders are controlled and operated by the agency of electric wiring, and. accordingly another feature of the invention consists in an arrangement of electrical circuits including primary controllers with which to execute the playing, and secondary controllers or selectors, such as draw-stops. each of which, when in operative position. determines which and how many harmonically related sounders will operate conjointly and also the relative forces with which they will operate when brought into play by the primary controllers. I

The intensity and the combinations of the component sounds are preferably predetermined by the wiring of the several draw stops, thus relieving the performer from all mental and physical effort other than setting the draw stop that bears the name of the tone quality desired.

The illustrated apparatus includes a set of sounders'representing, collectively, all the notes of an equally tempered chromatic scale which may have any desired range. lissuxn ing that the instrument is intended to be played manually there will be a separate sounder for each ltcy of the manual.

lly suitable electrical connections a single movement ot a draw stop will combine the sounders that correspond in frequency of vibration to the several partials of a compound tone, and will also determine the intensities with which the combined Sounders will operate.

1 have found that more satisfactory nulsical results are obtained by compounding simple harmonic motions simultaneously, and with different degrees of amplitude, than by translating complex wave motions into correspondingly complex air motions. So far as I am aware no apparatus has been produced heretofore to accomplish this result in a musical instrun'icnt, and I desire the broadest possible interpretation of the claims hereinafter set forth.

Referring to the accompanying drawings, which are diagramumtic, l have divided the complete showing for two notes and two different tone qualitics into three figures, to

avoid complexity.

On the drawings.

Figure 1 represents a wiring diagram that is complete as to one pitch and two tone qualities thereof- Although rovision is made herein for only two combinations of Sounders and only two different intensities of each sounder, this showing is sufficient to indicate how provision may be made for additional combinations and additional intensitics.

Figure 2 represents a wiring diagram that is complete as to two contiguous pitches and two different intensities for each sounder, the draw stop connections being omitted for the sake of simplicity. The draw stops and their five contacts corresponding to the first five partials of each itch are intended to have the same tonal e sets as the draw stops included in Figure. 1. I

Figure 3 represents a wiring diagram illustrating the relation in which the sounding circuits are cross-connected to provide for operating the sounders to furnish harmonics in addition to fundamentals;

For convenience of expression the word partial is herein used to mean the component sound furnished by each of the SOlll'KlClS contributing its motion to the production of a compound tone, with no distinction between the fundamentals and the harmonics.

In the use of reference characters, numbers and letters are combined according to the Following scheme: a letter preceding a numeral signifies that the element indicated is duplicated for each note of the chromatic scale, while a numeral followed by a letter mousse indicates an clcmcntfor coupling hormone cally related soundcrs.

A source of direct current, such as a hattery, is indicated at l). -Battcry leads and ii are the principalconductors of the sounding circuit, which is represented by relatively heavy lines. 'lfh rm sounding circuit is used to identity t cuit that operates the sounder-s, The con oiling circuits by which the partials arc cor lined and their dililcrent intensities selected, ind those by which they are brought into play, are represented by relatively light lines.

v in Figure 1 l have shown a primary controller or switch 70, such as the key of a manual. lit will be understood that in the case of an automatic player some other form of primary switch could be provided instead of a manual key. The sounder for the fundamental pitch, or first partial, appertaining to the key is indicated at G. In the present instance the sounder is represented as comprising a nodally mounted steel bar g havin a resonator r'. The soundcrs indicated at (3 G G, and G are harmonically related to the fundamental sounder, the superiors 13, and 29, representing the numerical order of the semi-tones in the chromatic scale, assuming that the fundamental tone is regarded as the first. In like manner these superiors have the same significance wherever they occur. All the Sounders included in a set or scale are preferably alike in kind, but differ in size and pitch, but for the sake of simplicity, I have omitted reference characters appertaining to the steel bars and resonators excepting those of sounder w. The steel bar of each sound generator is tuned to execute simple harmonic motion of a normal l re ucncy corresponding to its position in the c romatic scale. Each sounder is caused to vibrate, in every instance, with its normal t'rc uency, and never with a multiple thereof, an for this purpose I prefer electromagnetic exci'ters such as those indicated by the letter a with appropriate numerical superiors corresponding to their ositions in the scale. Direct current from attery b is utilized to energize the exciters, the current being interrupted as to each exciter with a frequency corresponding to that of the sounder excited thereby. Continuously driven rotary interruptcrs c (with appropriate nu mcrical superiors) are arranged in series with the excitcrs respectively. The interrupted current passes through adjustable rhcostats R et cct'cra, which are intended to be adjusted collectively by the performer at the instrument to regula e the volume of sound.

.The manual key k is'not included in the sounding circuit, but is in a controlling circuit 12, one side of which is connected to battery lead 10, and the other side to battery lead 11. Each key circuit includes a relay magnet, that for the circuit of key 70 being indicated at m. This magnet, when energized, connects battery lead 10 to a plurality of branches 1, 2, 3, t and that couple sounders G G G G and G thereby causing said sounders to operate simultaneously, and since they are all harmonically related to each other and give simple tones respectively, they produce a synthetic tone having no undesirable partials. lnthepresentinstance,havingshown branches for producing the first form harmonies in addition to the branch for producing the fundamental tone, I have provided with each primary controller a sounding switch having live movable contacts all of which are responsive to the magnetic influence of the magnet m. These five contacts, indicated respectively at 1 2 8 al and 5 close the connections between battery lead and branchcircuits l, 2, 3, l and 5.

in the present instance I have shown provisions for giving two dilierent relative intensities from each sounder, although it will be understood that there maybe provisions for a greater number of intensities. As hereinbefore stated I have found that tour different intensities for'each sounder afford substantially all the different tone qualities that will be useful, and while it have shown provisions tor two difierent intensities, it will be understood that additional intensities may be provided by duplicating the branches now to be described.

Each of the branches 1, 2, 3, d and 5 is divided into two branches, the latter being indicated (reading from left to right) i, l, l, 2', 1 2' 1 5 l, and lilaving shown means for regulating the intensities of each sounder with two difi'erent degrees, it have used capital letters where the greater'intensity occurs, and small letters where the lesser intensity occurs, thus indicating by the rank of letter the corresponding rank of intensity.

Referring to the branches or branch 1 it will be observed that I? does not contain any resistance, this branch being intended to make the connection of the sounding circuit to the exciter or the fundamental tone with relatively great intensity, whereas the branch 2" includes resistance intended to decrease'the intensity of the fundamental tone, subject to the control aft'orded by the draw stops; All the branches are initially disconnected from the 'exciters but are connected with said exciters in any desired combination by pulling the draw stops. Connection is made between the subordinate branches and the exciters by multiple switches, ten of which are represented in cachet the figures by the reference characters 1, 1 2 2 3 3 l l 5 5 The fact that it have shown'ten of these multiple switches is due to the fact that the showing provides for five partials and two intensities of each partial, but in practice, assuming that theinstrument is equipped for four intensities for each of five partials there would be twenty multiple switches. In other words there will be a separate multiple switch for each intensity of each sounder. Each multiple switch is provided with an electro-magnet, which, when energized, completes the connection between the exciter and the branch with which the multiple switch is associated. Each multiple switch has a num ber of movable contacts equal to the number of primary controllers c et cctra. Figure 2 shows the multiple switches as having only two movable contacts because only two primary controllers are represented. 'llwo draw stops are indicated at and @ne side of each draw stop is connected to battery lead 10, and each stop, when moved to a circuit-closing position, engages five stationary contacts, the latter'being the terminals of regulating circuits 1 2 3 l and 5 respectively, These regulating circuits correspond respectively to the first five partials of a compound tone and there may be as few or as many controlling circuits as desired, within the total number provided for, according to the combination desired. In the pres ent instance draw stop D makes connections through the maximum number of regulating circuits, whereas draw stop l)" makes connections through but three circuits, the latter beingindicated at l 3 and 5*. Referring to the circuits controlled by draw stop .u, circuit P is connected to magnet l, the lower grade or rank of the letter m incl-- eating a relatively low degree of intensity of the sounder brought into play therethrough. Circuit 2 is connected to the magnet 2 grade or rank of the letter M indicating a relatively high degree of intensity afforded thereby. in a similar manner the circuits 3*, 4 and 5 are, connected to magnets 3 i and 5", respectively. According to this combination draw stop D will select a low degree of intensity for the fundamental tone, a high degree of intensity for the first har-- monic, a high degree of intensity for the sec- 0nd harmonic, a low degree of intensity for the third harmonic, and-a low degree'ot' inten sity for the fourth harmonic, the net result as to tone quality when the degree of res1st- .ance in the branches ailected thereby is correctly predetermined, being equivalent to that of the oboe. When the draw stop D is in circuit-closing position, multiple switches 1 2 3 4: and 5 are moved to circuit-closing position by their respective magnets thus completing the electrical connections between all the exeiters a a etc, and the desired rcsistance coils of the'sounding circuits. The synthetic tone produced by this combination comprises a weak first partial (resistance 5 a strong second partial (resistance l), a strong third partial fourth partial (resistance 2') and a wear: fifth partial (resistance 6 (resistance 1 a weak:

lit)

Ill

' though, for the sake All the magnets that are associated with the multiple switches are connected to a com mon return wire, which, in turn, is connected to battery lead 11. The complete circuit of regulating circuit 1 without regard to direction, or polarity, is as follows: from battery I) to battery lead 10, draw stop D, regulating circuit 1 magnetl common return to battery lead 11, back to the opposite side of battery Z).

Each multiple switch distinguished by S or c, with an appropriate numeral prefix, includes one pair of contacts for each key of the manual or other principal controller, al-

oi': simplicity, l-have shown only one pair or contacts for each multiple switch in Figure 1 because this figure includes only one manual key. in Figure 2, however, I have shown two manual keys, l, 71: together with con'iplete wiring connections for both of them. In this tigure'll have therefore shown each multiple switch as having two pairs of contacts, and further explanation concerning them will occur in due course. g

Referring to Figure 1, when the desired draw stop is moved to circuit-closing position it selects not only the desired combination of partials, but also the desired intensity for each sounder, the selection of intensity being direct because each sounding circuit has a multiple switch and companion magnet for each resistance branch. All the sounding circuits are thus com leted excepting at the points controlled b t 1e contacts 1 2, 3 4, and 5 of the scan ing switch, and the instrument is thus prepared for operation. 'W hen the primary switch it is closed, thus energizing magnet m, 25, l, and 5 are closed, and current will then flow from battery 5) through battery lead 1G, sounding circuits 1, 2, 3, d and 5, the branches previously selected by the draw step, through all the connected exciters of the sounders, through all the interrupters then in circuit, and through battery lead ll returning to battery. 3y reason of th fact the described apparatusproducessyntheti ctones and affords individual'control off each constituent tone, it great variety of com ound tones is made possible and no undesirable partials need ever be produced. As soon as the key 70' is released its magnet m is (lo-energized, and the sounding switch controlled thereby opens the circuits 1, 2, 3, t, and 5. Draw step ii) calls for only three simple tones "for each note (see Figure 1), viz, a strong fundamental tone, a weak octave quint, and a weak tierce, the synthetic effect produced thereby being similar to that of the clarinet. I

The showing of Figure 2 diiiters from that of Figure l in that it is incomplete as to the regulating circuits controlled by the draw stops,and includes an additional key 70 and all the additional elements le The fundamental tone 0 the note corthe sounding circuits 1i, 2, f

a pertaining to c resses responding to 70 is produced by the sounder Gi while the harmonics are produced by the sounders G, G, G and respectively. The exciters of these five sounders are-indicated at a, a, a, a and a, while the interruptors that belong thereto are indicated at 0?, 0 ,0 amend 0 The numerical superiors, it is to be remembered, indicate the relative order of the elements according to the positions of the sounders in the chromatic scale.

Referring to the multiple switches as shown by Figure 2, each switch is shown as having one movable contact for each of the two manual keys shown. Had it been attempted to show the full number of keys for a complete manual there would have been one movable contact for each key onthe manual, with corresponding duplication of the sounding switches and the branches and subbranches running therefrom to the stationary contacts of the multiple switches. In this respect to complete the equipment would require merely adding a sounding circuit for each additional sounder and primary switch, and adding: to the contacts of the multiple switches accordingly, so that each key would cause current to energize the whole number of exciters potentially coupled to it by the draw stop in circuit-closing position. Figure 2 shows how the current from battery 6 is caused to energize one or both relay magnets m, m and how the current is consequently caused to energize the exeiters that are brought into play by the manual keys and controlled in the first instance, as to combination and intensity, by the draw stop.

llnTaccor-dance with common practice with pipe organs, an instrument embodying the present invention may have two or more mannals, and when more than one manual is provided the elements and wiringshown by the drawings will be du 'ilicatcd, with the exception of the battery b, for eabh manual.

Figure 3 shows how the sounding circuits are interconnected so that each sounder may furnish a tone equivalent to a third partial as when G is brought into play by (see the same showing in Figure 1) and equivalent to a first artial, second partial, fourth partial, and ifth partial as when G is brought into play by 10 70, 70 and 7cre speclively. Here, the minus sign indicates that the controller is below 70' in the scale, and the numeral indicates its order or position reckoned trom Zc., Therefore, sounder G furnishes the fundamental for 70 the first harmonic for 70 the second harmonic "for in, third harmonic for Zrand fourth harmonic for 76 The showing of sounding circuit 1 (broken lines) as controlled by is is the same as in Figure 1 excepting that to it are added the sounding circuits 2, 3, 4 and 5 controlled by 76 70, 70 and krespectively.

till

sounders respectively.

By reason of these interconnections any sounder may be played by two or more primary controllers simultaneously, and when so played its playing force or intensity is equal to the sum of all the forces combined by the playing connections. Hence, for example, G may furnish the fundamental for 70 while furnishing the third partial for is, and its playing force in such case will be that ail'orded by circuit 1 of 70 plus that afforded by circuit 3 of is. As a general rule this interconnected relation obtains throughout the scale of sounders and relay switches, although, obviously, their number would be less in the two or more lower octaves of the scale.

I claim:

1. A musical instrument comprising sounders adapted to furnish a musical scale, electro-magnetic means for exciting the sounders individually, said means including playing switches to which the sounders are related as fundamentals respectively, relay switches responsive to the control of the playing switches respectively to connect for conjoint operation with each fundamenetal sounder one or more other sounders harmonically related thereto, resistance elements,-

means for putting said resistance elements into circuit selectively to produce. a predetermined tone quality from each group of sounders put into play conjointly as afore said, and one or more controllers each arranged to determine which harmonic sounder or sounderswill be put into play conjointly with each fundamental sounder and simultaneously to determine which resistance elements will be put into the circuits of said 2. A musical instrument comprising sounders adapted to furnish a musical scale, playing switches to which said sounders are related respectively as fundamentals, means controlled by said playing switches for coupling automatically with each fundamental sounder for co-operation therewith a plurality of other sounders harmonically related thereto and related as fundamentals to other said playing switches, playing controllers for selecting simultaneously a predetermined combination of sounders, harmonieallyrelated to each other, andmeans cont-rolled by said playing controllers to give said sounders so selected relatively"difierent intensities.

3. A musical instrument comprising sounders adapted to furnish a musical scale and the harmonics thereoi each of said sounders being so constructed as to produce only one simple ,harmonic motion or sine wave in the air, and means for exciting the sounders individually, said means including playing switches to which the sounders are related as fundamentals, respectively, a plurality of tone-quality controller-switches, one for each separate prcdetern'iined tone quality in which the instrument may be played, multiple contacts co-operating with said controller switches equal in number to the largest number of harmonically related sounders it is desired tosimultaneously sound together, electrical wiring to said multiple contacts and apparatus included therein for selecting for each said tone-quality controller-switch which harmonically related sounders shall be grouped together and for simultaneously determining the relative intensities of said sounders so grouped.

4. In a musical instrument having sounders adapted to produce simple harmonic motion in the air and to furnish a musical scale, playing switches to which said sounders are related, respectively, as fundamentals, means controlled by said playing switches for operating the sounders, and unitary means to connect for conjoint combinations of sounders harmonically related to each other and simultaneously to regulate the intensities relatively to one anothgr of the tones produced by the sounders.

In testimony whereof I have afi'ixed my signature.

SEWALL OABOT.

operation predetermined

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