US2237105A - Apparatus for the production of music - Google Patents

Description

April 1941- B. F. MIESSNER 2,237,105

APPARATUS FOR THE PRODUCTION OF MUSIC Original Filed March 5, 1936 3 Sheets-Sheet l I I IIK 621 63 [NVEN TOR:

April 1, 1941. MIESSNER 2,237,105

APPARATUS FOR THE PRODUCTION OF HUSIQ Original Filed March 5, 1936 3 Sheets-Sheet 2 22/ 2Z3 INVENTOR:

April 1941- B. F. MIESSNER 2,237,105

APPARATUS FOR THE PRODUCTION OF MUSIC Original Filed March 5, 1936 3 Sheets-Sheet 3 Patented Apr. 1, 1941 UNITED STATES PATENT. orrlca APPARATUS FOR THE PRODUCTION OF MUSIC Benjamin F. Miessner, Millburn Township, Essex County, N. 3., assignor to Miessner Inventions, Inc., a corporation of New Jersey Application March 5, 1936, Serial No. 67,245 Renewed July 26, 1940 23 Claims.

This invention relates to the production 01' music, and principally to such production by 758,155, filed December 19, 1934, I have disclosed an instrument operating by translation, as abovementioned, of the vibrations of reeds as above set forth; and this application in many of its aspects deals with improvements in and improved forms of such an instrument.

It is an object of my invention to provide a generally improved instrument of the class described.

It is another object to provide an improved assembly of reed and reed-block for such an instrument.

It is another object to provide an improved arrangement of reed-block and reed-housing in such an instrument.

It is another object to provide improved arrangements of reed-housing, reed-blocks and electrodes.

it is another object to improve or to perfect the mutual tuning of certain harmonically related reeds.

it is another object to reduce beats and other undesirable manifestations resulting from simultaneous playing of mutually near-by reeds.

It is another object to provide means for producing tones having particular envelopes, or amplitude-time characteristics.

It is another object to provide an organ of improved flexibility in respect of certain tonal characteristics capable of production simultaneously or in immediate alternation.

It is another object to provide an. organ with improved and simplified inter-manual coupling arrangements.

Other objects are to provide improved means for determining the tone inception and terminait is another object to reduce residual acoustic sound output from an instrument of the class described.

It is another object to improve the shieldings,

both electrostatic and acoustic, or portions of V I for equalizing or specially adjusting the rates of inception of the tones produced by the instru; ment.

tion in an instrument of the class described, and to provide an instrument with which such means and conventional means are alternatively available.

Still other objects are to provide an improved arrangement of reeds and translating means for each of the several notes of an instrument of the class described, and to provide improved reed and reed-excitation means in association therewith.

Further objects are the provision of improved methods for the production of musical tones from tuned vibrators, and of operating instruments of the class described.

Other and allied objects will more fully appear from the following description and the appended ciaims.

lo the description reference is had to the accompanying drawings, of which Figure 1 is a view, partly cross-sectional and partly schematic, of an instrument according to my invention;

Figure la is a schematic view, intended for optional substitution for a corresponding portion of Figure 1, illustrating an optional alternative mode of operation;

Figure 2 is a cross-sectional view taken through one of the reed-housings of Figure l, in similar plane and disposition to that figure;

Figure 2a is a cross-sectional view taken along the line 2a of Figure 2, Figure 2 being taken along the line 2-2 of this figure;

' Figure 2b is a cross-sectional view taken along the line 2b of Figure 2a;

Figure 3 is a cross-sectional view, generally corresponding to Figure 2b but illustrating the preferred arrangement of another of the reed housings of Figure 1;

Figure 3a is a cross-sectional view similar to Figure 2a, but illustrating the employment of reed assemblies as shown in Figure 3;

Figures 4 and 4a. are each cross-sectional views similar to Figure 3, but each illustrating a different modification of the structure of that figure;

Figure is a partial bottom view of one of the reed housings of Figure 1; and

Figure 6 is a view, partly cross-sectional and partly schematic, of an instrument according to my invention but modified in certain respects from the instrument of Figure l.

A view, partly sectional and partly schematic, of a simple instrument according to the invention is shown in Figure 1. The sectional portion is taken in a vertical plane passing through one of the keys I of the instrumentfor example a white key. In this figure will be seen a horizontal base 2, to which the keys are pivotally assembled by arrangements not necessary to show. Underneath the base is formed a suction chest 3, in which it will be understood that there is maintained an equalized vacuum of appropriate degree. Passing through the base 2 into the chest 3 are a plurality of apertures l, one for each note or key of the instrument. Each of these apertures is normally closed by a key-controlled valve 5. Such a valve 5 has been shown as comprising a wood or other rigid strip 6 provided with holes freely fitting around two pins I arranged in front of and behind the respective aperture 6; a felt or other soft topping 8 secured to the strip 6; and a spring Q secured to the base 2 and urging the strip E upwardly to seat the topping 8 firmly against the bottom of base 2 over the respective aperture l, closing the valve. The mechanism for opening each valve is simply a respective push rod Ill freely passing through base 2, with its bottom resting on top of the forward portion of the respective strip 8, the top of the push-rod extending into at least substantial contact with the bottom of the respective key, so that upon key depression the valve will be opened.

Secured to the base 2 above the apertures t is a vertical channel-block I I, provided with a plurality of vertical channels or ducts l2 each in alignment, and thus communicating, with a respective one of the apertures l. Passing from the back of the channel-block II into communication with each one vertical duct l2 are a plurality of horizontal branch ducts, the plurality being shown by way of example as I3, I3, I3". The illustration is of course in vertical section-i. e., for a single key or note-and it will accordingly be understood that extending across the instrument there is a horizontal row of branch ducts IS, a like row of branch ducts I3, and a like row of branch ducts I3". To the channel-block II, over each of these rows of branch ducts, is secured a. separate reed-housing carrying one or more reeds for each note, the housings being designated as I 3, I 5 and I6" respectively. In order to minimize conduction of reed vibration through the reed-housings to the main structure oi. the instrument-e. g., to the channel-block II-the reed-housings may respectively be secured to vibrationally insulative members, I5, I5, I5"-for example sponge rubber strips-and these in turn to the channel-block Ii.

A typical form of construction of a reed-housing.

I6 with reeds in place therein, is shown in Figures 2, 2a, 2b; Figure 2 is an enlarged cross-sectional view taken in plane and disposition similar to ure 1. The housing is of course of insulating material, such for example as a good grade of wood. In it are provided a plurality of cells l6- one for each note of the instrument-communicating with the atmosphere at their rear or outer (or, in Figure 2, left-shown) extremities Wu.

Each cell, in a strip around its bottom, is enlarged to form a slot I'I into which the reed-block I8 (carrying the reed) may be slipped. Beneath each cell, as shown in Figure 2, is an individual housing-duct I9, which is provided with an -nlarged portion I9a communicating with that cell. It will be understood that when the reed-housing is assembled to the channel-block I I the housing ducts I9 for the several notes respectively communicate with the several branch ducts I3. When a valve 5 is opened, air is sucked through the associated channel-duct I2 and (as illustrated) three branch ducts I3 and housing ducts I9, vibrating simultaneouslyall the reeds positioned in those three cells which respectively communicate with those three housing-ducts.

The reeds themselves are shown as 20. Each may be formed of metal, and may if desired have an enlarged base ZI to which it is secured or with which it is integral. The base 2| is secured, as by rivets 22, to the top of the block I8. This is generally rectangular, and is provided with an aperture 23, extending from about the junction of reed with reed base to just beyond the free tip 26a of the reed, and of width slightly greater than that of the reed-the latter is accordingly free to vibrate in and out of the aperture. Preferably the aperture is provided on the bottom of the block with a chamfer 24. It will be understood that the arrangement of each cell I6 and respective housing-duct I9 (with portion I9a) is such that when the reed-block is slipped into its slot I? communication between cell and duct takes place only or substantially only through the aperture 23 in the reed block; in this aperture the reed is positioned, and it is of course the air flow through this aperture when the appropriate valve is opened which vibrates the reed.

While the reed, reed-base and reed-block assembly as so far described may be considered entirely conventional, I prefer to depart from conventional practise in the choice of material for reed-block, making this of phenol-resin composition or other insulating material rather than of metal; it will be understood, however, that this change is not indispensable, and that I may as conventionally form the block of conductive material. The practise of employing insulating material has a specific advantage hereinafter mentioned; but more importantly, it has the general advantage of improving the efiiciency of the translation and the accuracy with which the harmonic structure of the electric oscillations will conform to that of the reed Vibrations, particularly in connection with the translation by the bottom-shown electrodes 29. For these are subjected to a material constant influence by the field of the reed-block 18 when this is conductive, and this constant influence to an appreciable extent overshadow the desired vibrationally varying influence of the reeds on the electrodes in question. In converse terms, the reed block extends into the fields of the translating apparatuse. g., into the fields of the electrodes, and in the case of the bottom-shown electrodes 29 to a very large degree-and, when it is of conductive material, largely nullifies the effect on those fields of the conductive reed vibration.

For the translation of the reed vibrations into electric oscillations f: prefer to employ electrostatic, or capacitive, translation; and the simple embodiments of this translation require a conductive connection to the reed. In order to make this connection in simple manner, and at the same time to preserve ready removability of the reed-block from the reed-housing, I provide means in the reed-housing which automatically connect with the reed upon insertion of the reed- 21 and rivets 22 serve to complete the connection of reed to screw 25.

The electrostatic, orcapacitive, translation requires the positioning of one or more electrodes near a vibrating portion of the reed. As I have pointed out in my co-pending application above referred to, I prefer to employ at least two electrodes in association with each reed-one thereabove and one therebelow. Such electrodes in Figures 2, 2a, 21) have been illustrated as screws 28 and screws 29, respectively. Each screw 28 passes downwardly through the top of the reed-housing into the respective cell I6, being shown in Figure 2 by way of example with its extremity a little above a point on the reed near its free tip 20a. Each screw 29 passes upwardly through the bottom of the reed-housing into the enlarged duct, I941, with its extremity a little below a like portion of the reed. The precise desirable spacing of the screw extremities from the reed will depend among other things on the amplitude of vibration of the reed (as influenced by the degree of the suction employed for vibrating it, its parameters such as dimensions, shape, relationship to its cell, etc.), it being understood that the spacing will always be great enough so that the electrode (screw) is not hit by the reed. In some cases the desirable adjustment'of-the bottom screw 29 may be such as to bring its extremity above the plane of the bottom of the reed-block |8i. e.. sticking into the aperture 23 in reed-block 58; under these circumstances, with a reed-block of normal construction, the adjustment of the screw 29 would have to be disturbed to remove the reed-block. To obviate this I may provide, in the bottom of the reed-block between its inner end and the aperture 23, a central channel '32 at least slghty wider than the screw 29-which channel will clear the screw, even though the extremity of the latter be adjusted above the bottom plane of the reed-block.

As I have further pointed out in my mentioned co-pending application, the fiexibilityof control over the translation of the reed vibrations may be increased by providing, in addition to the two electrodes already discussed, further electrodes which are most closely approached by some portion of the reed at intermediate rather than extreme points in its vibrational travel. I find it desirable, in a construction such as I am describing, to mount such additional electrodes to the reed-blocks-these being in such event necessarily formed of insulating material, or at least having associated therewith such material appropriately placed, to permit the electrical isolation of reed and electrode. These electrodes must be connected to; and to do this without impairing the ready removability of the reed-blocks I associate with each of the electrodes in question contact means which automatically connect the electrodes upon insertion of the reed-blocks into their slots. An embodiment of this has been shown in Figure 2, wherein an electrode and contact means have been shown as an integral spring 30 riveted to the top of the reed-block at its inner end, having an outer extremity 30a in very slight spaced relationship to the path of travel of the reed tip 20a, and having an inner portion 30b bent to contact upon block insertion with a screw 3| passing downwardly through the top of the reedhousing into the cell l6 near the inner extremity of the latter.

In my mentioned co-pending application I have suggested for full harmonic development the use of a plurality of simultaneously-blown reeds per note; and, in view of the great ease with which octave partials are developed from each reed, have mentioned as an example of frequency ratios for agroup of three reeds the series 1:3:5. I have found this series in general a good one, but I have shown the instrument of Figure 1 as embodying four reeds per note-i. e., having another integer added to the series above mentioned; this may be chosen as desired, but by way of example may be considered the integer 4. For convenience I shall refer to the four reeds per note respectively as the fundamental, third-partial, fourth-partial, and fifth-partial reeds, but it is to be understood that this is not to be taken in a limitative sense.

The reed-housing H of Figure 1 may for example house the flfth-partial reeds for the several notes, it being understood that an individual one of the housing-ducts I9 communicates with a respective one of the branch ducts l3. The reed-housing H of Figure 1 may be formed similarly to the reed-housing H, but may house the fourth-partial reeds for the several notes; each individual one of its housing-ducts of course communicates with a respective one of the branch ducts l3. (The portions of the housing i4 appearing in Figure 1 have been designated similarly to the corresponding portions of housing 94, excepting that they have been furnished with prime marks.) While the reed-housing M" of Figure 1 might be entirely similar to the other housings of that figure and contain only one reed per note, I have illustrated it as slightly modified to accommodate two reeds per notee. g, the fundamental and third-partial reed-s and in Figures 3 and 3a have illustrated the features of modification from the reed-nousing 54.

Before proceeding to a more detailed description of these modifications, I may first point out the underlying reason ,for desiring a plurality of reeds per note in the same housing. This lies in the greater opportunity for close coupling of the plurality for each one note. This close coupling-which may be mechanical and/or acoustical--I have found highly advantageous in effecting precise relative tuning of the plurality of reeds in question. It is well recognized as almost impossible to efiect absolutely perfect relative tuning of two dissociated reeds-th best that can reasonably be expected is the prolongation to several seconds of the period of any 'beat between coincident partials. But if the reeds are sufliciently closely coupled, then although their relative tuning be not absolutely precise they will suiliciently react upon each other to pull into, or lock in, an absolutely integral frequency relationship. Some measure of this coupling, of an acoustic nature, between reeds or the same note is obtained by the passage oi the air-streams which vibrate them through a common duct-which is then preferably made as small as consistent with satisfactory and reliable blowing with proper suction or pressure at each reed (the suction in the main,

chest being thereto appropriately established). In other words, some measure of this coupling is efiected in the instrument of Figure 1 in the duct l2 for each note. Further acoustic coupling, however, may be made to take place in the housing-ducts i9, and opportunities for other acoustic and for mechanical coupling are created, if a plurality of reeds are appropriately positioned in each individual cell; and this has been illustrated in the Figures 3-311.

It will be understood that in these figures the portions similar to Figures 2-2a-2b have been provided with similar designations, excepting that they have been furnished with double-prime marks. In these figures two reeds and 20" have been shown formed from or secured to the common reed base 2!", which may in turn be secured to the reed-block it" in the same manner as heretofore. The reeds, being typically fundamental and third-partial reeds respectively for the same note, may of course be of different lengths and/or thicknesses and/or widths. Lying essentially in the same plane, they may be separated by a very slight distance-of the order of the usual reed-to-aperture-edge spacin in the case of a single reed. The block it" may be provided with a single aperture 23" which conforms with slight spacing to the periphery of the pair of reeds. It will be understood that by this construction acoustic coupling between the two reeds is effected in the housing-duct iii"; in the enlarged duct portion 89a"; in the cell it"; and, very importantly, in the aperture 23" itself. Furthermore a very significant mechanical coupling is effected by the common base 2i" for the two reeds. Of course the number of reeds which may be so treated is not limited to two, this number having been illustrated herein by way of example only.

While the arrangement of Figure 3 is advantageous in that the common base 2i" provides particularly good mechanical coupling, separate bases may however be employed for a plurality of reeds which are still secured to the same block to obtain considerably mechanical coupling, and which work in a common aperture to retain close acoustic coupling. Two alternative constructions of this character are shown in Figures 4 and 4a, respectively. In Figure 4, wherein have been employed designating numerals higher by 200 than in Figure 3, reed-bases 228" and 225?" are at opposite ends of the block, with the reeds pointing at each other and working in the common aperture 223". In Figure 4a, wherein have been employed designating numerals higher by 300 than in Figure 3, the reeds are in general similarly disposed, excepting that each is displaced to a respective side of the block to permit the overlapping of the reeds as to longitudinal extent, the common aperture 323" being appropriately oflset. In these figures the springs 23@" and 330" are not intended to form end electrodes, but rather are the means of making available 'a connection to the reeds 228" and 326" respectively through the respective screws 235" and 33!".

Returning to Figure 3, it will be understood that the spring 8i3"-generally similar to spring 38 of earlier figures but slightly oiiset to bring it into alignment with the end of the fundamental reed 20". forms an end electrode for that reed, and screw 3!" a means of automatically contacting this electrode. The reed-housing l4", similarly'to the housing It, is provided with screws 25" for reed contact, screws 3!" for the end electrodes, screws 28" in alignment with the fundamental reeds to form top electrodes therefor, and screws 29" in similar alignment to form bottom electrodes for the fundamental reeds; additionally it is provided with screws 28" similar to screws 28" but positioned relatively nearer the outer end of the reed housing and in alignment with the third-partial reeds to form top electrodes therefor, and with screws ZQ' similar to screws 29" but correspondingly arranged to form bottom electrodes for the third-partial reeds.-

While there has been pointed out as desirable the coupling of reeds which are simultaneously vibrated in the playing of any one note, material coupling together of reeds of respectively difierent notes is usually objectionable; it has the eii'ect, particularly in the case of coupling between adjacent reeds separated in frequency by a half-tone interval, of badly accentuating the beats between those notes when simultaneously played. In ordinary constructions a very significant acoustic coupling of this nature occurs. means to suppress this coupling, in association with each of the reed housings. These means have been illustrated in detail in Figures 2 and 2a. The major portion thereof consists in a cellextension structure which has the effect of extending the individual cells it; this structure may be formed by two rigid plates 36 provided with the flanges 36a, rigidly spaced apart by any suitable means, and by thumb-screws 34b passing through the flanges iila secured in horizontally extending position from the outer end of the reed housing-one above and one below the open ends of the cells HE. From one of these vanes to the other, between each successive cell it, is secured a partition as, which is desirably of soundabsorptive material such as felt; the inside surfaces oi the plates 36 between the partitions may also be lined with felt 3Y7. The effect of these individual cell extensions thus provided is to provide a markedly increased sound pressure gradient within the spaces which are individual to the several notes, so that less sound energy from each cell drops in the common space therebeyond. This effect can be heightened, and at the same time a very decided and beneficial reduction effected in simple acoustic output from the instrument, by providing over the otherwise open outer face of the cell extension structure-.33 a layer of porous felt Mi.

It is possible, of course, for some coupling between successive reeds to take place on the other sides of the reedsi. e., at the termination of the ducts in the common chest 3. In view of the length of the ducts in the instrument of Figure 1, this may not be found therein a serious efiect;

but as an illustration of duct lining with soundabsorptive material for its suppression, I have in Figure 2 shown the enlarged duct portion i9a lined with felt (i2.

I therefore prefer to provide de-coupling top of the channel-block i l. The inside of this cover may first be lined with an air-porous electrostatic shielding 45, 'for example of copper screening material, and thereover with a layer of soft and porous felt 46. To permit passage of air through these linings forthe blowing of the reeds, the cover may be provided with suitable apertures, such as those indicated in its top portion as 41. The electrostatic shielding 45 has been shown connected through the screw 48 to the hinge 44, the latter being connected to ground (which will be understood to be used in this specification not in the rigorous sense of true ground, but rather as denoting a reference potential). Substantially to complete the electrostatic shielding of the reed-housings, grounded electrostatic shielding 49 has been shown on the front surface of the channel-block II, and grounded like shielding 50 on the top of base 2 within the covered area. It will of course be understood that the vertical portion of the cover, with its electrostatic and acoustic shieldings, is continuous, being broken in Figure 1 only as an incident to the schematic showing of the more purely electrical portions of the instrument;- the continuity of the electrostatic shielding 45 has been schematically illustrated by the dotted line.

The more purely electrical features of the instrument may now be considered. It will of course beunderstood that each reed has associated therewith a plurality of small capacities responsive to its vibration-i. e., the capacity from the reed to each of the adjacent electrodesand that the vibration of the reed is intended oscillatorily to vary a voltage across each of these capacities.

The voltage maintained in the first instance across each of the capacities may be direct, in which case it is applied through a high resistance to stabilize the resulting charge in the capacity so that the vibratory capacity variations will modulate the steady voltage to produce the oscillatory voltage variations; or it may be an alternating voltage of a super-audible carrier frequency, again preferably applied through a resistance, the vibratory capacity variations serving to modulate the carrier frequency voltage across the capacities with the desired oscillations (the latter being eventually made available in simple form by de-modulation) The instrument of Figure 1 has been illustrated as employing the first of these alternatives.

The function of the plurality of capacities is to permit the production across the respective capacities of voltage variations which are of mutually different waveform and/or havebetween them a significant phase difference. A composite oscillatory voltage is combined or compounded from across the several capacities, and by controlling the respective contributions of the several capacities to this composite voltage a control of oscillation harmonic structure, and of output tone timbre, is effected. In general, two arrangements for obtaining control of these contributions are available. In one there are controlled the amplitude and polarity (or phase) of the voltages applied in the first instance across the capacities; the oscillatory voltage variations are thereby controlled because the degree or percentage of modulation of these voltages remains essentially constant. The other arrangement is one wherein voltages mutually similar (or of fixed relative amplitudes and phases) may be applied in the first instance across the several capacities to produce oscillatory voltage variations, or oscillations, of fixed relative characteristics; the several series of these oscillations (one from each of the capacities) are then controlled in respect of relative amplitudes and phases before their combination. In the instrument of Figure 1 the first of these arrangements has been illustrated.

It will of course be understood that, for simultaneous control of the tone quality of all notes of the instrument, there may be paralleled to form a single capacity the capacities between the several reeds and their respective top electrodes; to form another single capacity, the capacities between the several reeds and their respective bottom electrodes; and so on. To do this in the instrument of Figure 1 there are connected together the several reeds in each one housing; there are connected together the several top electrodes in each one housing; and so on. To effect connection together of the several reeds in each one housing, there is secured on the latter a metal strip 35 (or 35' or 35") through which the reed connecting screws 25 (or 25' or 25") are threaded before passing into the housing. Other similar metal strips are secured on each one reedhousing to parallel the other corresponding electrodes or screws thereine. g., on housing W are secured strip 38" for screws 28", strip 38" for screws 28", strip 39" for screws 29", strip 39" for screws 29", and strip 4|" for screws 3l"-the strip in each instance being designated by a number higher by 10 than that of the screws which pass through it.

In. the instrument of Figure 1 the three strips 35, 35, 35" are shown connected together (paralleling all the reeds), and are connected to ground through the charging resistance 5|, which comprises the high resistance above referred to; to the other stripsi. e., to the various electrodesare applied direct voltages regulable in amplitude and polarity relative to ground. It will be appreciated that whatever oscillatory voltages appear across the several capacities, appear also in mutually superimposed or combined form acrossthe resistance 5|. Across the resistance 5| is connected, through condenser 52, the input of an amplifying and electro-acoustic translating system which is shown by way of example only as comprising the amplifying tube 53, the further amplifier 54, and the loudspeaker 55. For the tube 53 there has been shown a leak resistance 56, a by-passed self-bias resistance 51, a source of plate current or battery 58, and an extension SI of the electrostatic shielding 45 to surround at least tube 53, grid leak 52, and the resistances 5| and 56; in association with the amplifier 54 there has been illustrated a potentiometric volume control 59, controlled by a pedal 60. It is to be understood that this showing of amplifying and electro-acoustic translating system, and of control means in association therewith, is intended in no way as comprehensive, but as exemplary only.

In Figure l the means for applying the controlled direct potentials to the various electrodes, or to the several strips 38, 39, etc., have been illustrated as the conductors 68", 59", 68", 69", 68', 69', 68, 59; the switch system 62; the potentiometers 18", 19", 18", 19", 18, l9, l8, l9; and the battery or other voltage source 63. The last mentioned may have a grounded central or intermediate point, and extremities across which are connected the several potentiometers just mentioned. Each of these preferably has a variable contact, designated for the potentiometer 19 only as 54, and a plurality of fixed contacts,

designated for the same potentiometer as 65. The switch system 62 comprises a plurality of singlethrow switches, shown as 62a, 62b, 620; each having a plurality (shown as eight) of poles respectively connected with the conductors 8B", 69", 68", etc.; the switch 620, when closed connecting each of these conductors with the variable contact (e. g. 84) on a respective one of the potentiometers 18", 19", 18', etc.;. and each one of the other switches when closed connecting each of the mentioned conductors with one of the fixed contacts (e. g. 65) on a respective one of the potentiometers.

For the sake of simplicity only a single conductor'68" (and potentiometer 18'', etc.) has been shown for both strips 38" and 4|"; correspondingly only single conductors 68' and 68 (etc.) for 38'4,l' and for 38-, respectively. To make available,,in 'view of this restriction, the action of both top and end electrodes (to which the two strips on each housing respectively connect) I have shown the conductors in question running to single-pole double-throw switches 10", I and 1|), respectively, whereby either the top or end electrode strip may be selectively connected with the conductor. It will be understood that this arrangement is purely optional, and that instead thereof the number of potentiometers and conductors may be increased to a full one per strip.

The switches of the system 62 are intended in the simple case for alternate rather than simultaneous closing. When switch 62a is closed the variable potentiometer contacts may be manipulated to control the output tone timbre. When any of the other switches are closed there is produced an output timbre which depends on the positions of the fixed potentiometer contacts to which that switch makes connection, these fixed contacts having been positioned by test to produce a desired timbre. The manipulation of the switches in the system 62 will, in the absence of appropriate preventives, cause abrupt changes of potential on the electrodes, with resulting transients or clicks in the output sound. A simple preventive has been shown in Figure 1 in the form of low-pass filters ll inserted in each of the conductors 58", 69", etc.; each filter may for example comprise one or more stages of series resistance Ma. and shunt capacity lib.

If desired there may be incorporated an arrangement which permits a plurality of the switches to be simultaneously closed to produce an average" of the timbres respectively produced by the individual closings of those switches-by average is meant the superimposition of the timbres, but at reduced amplitude. This arrangeinent comprises an individual relatively high resistance in series with each of the contacts of each potentiometer, and has been indicated (for simplicity in association only with the potentiometer l9) by the resistances 6B. The averaging above mentioned may, however, be changed to approximate true superimposition of timbres by associating with the switches means whereby the amplitude of the combined oscillations is increased in substantial proportion to the number of switches simultaneously closed. While a varlety of such means are of course available, I have illustrated a simple one which may be described as follows: A resistance BI is connected into the circuit of amplifier 54 in any manner appropriate to effect a reduction of gain of the amplifier as the value of the resistance is increased, and vice versa. A plurality of additional poles 12a, 12b,

120 are provided, one for each of the switches 62a, I

621), 82c, and each pole is arranged when its switch is closed to short out a portion of the resistance 61. Thus the more switches are simultaneously closed, the greater the amplitude of the output is rendered.

In general, for desirable output tone qualities, the amplitudes of oscillations developed from the several reeds of each one note will on the average decrease as the ordinal number of the reed increases-1.5a, will be less from the third-partial reed than fromthe fundamental, still lessfrom the fourth-partial reed, and in turn less from the fifth-partial reed. Because of this average phenomenon, it will be found that if the several potentiometers l8, l9, I8, 19', etc., are all simply connected across the battery or other source 63, the adjustment range and criticalness will be progressively more excessive as the top-shown extremity of the series of potentiometers (e. g., the potentiometers l8 and 19, for the fifth-partial reeds) is approached. I accordingly embody in the circuit means for progressively reducing the potentials applied to the higher-numbered reedse. g., for reducing the potentials applied across the potentiometers electrically associated with those reeds. This is very simply done by having the potentiometers 18" and 18" (for the fundamental reeds) connected to receive full battery or source voltage; and by connecting the potentiometers 18" and 19' (for the third-partial reeds) across 18" and 19" through mutually similar voltagereducing resistances 13", the potentiometers 1B and 19' (for the fourth-partial reeds) across 18' and 19" through mutually similar resistance I3, and the potentiometers l8 and 19 across 78' and 19 through mutually similar resistances 13.

It will'of course be understood that while the potentiometer system controls the translation by all the electrodes 28 as a unit, the translation by all the electrodes 29" as a unit, and so on, the translations by these electrodes from note to note is regulated for uniformity, for proper balance between bass and treble, and for other desirable characteristics, by adjustments of the individual electrode screws, or instrument voicing. This operation in musical instruments of this general mechanico-electric type being already well understood, it will not be further discussed here. It

may be pointed out, however, that for ease of manipulation I have preferred to make the electrode screws of a type-for example hex-headedadapted to be manipulated by a wrench 'or like tool, rather than by a screw-driver.

In the particularly illustrated instrument, in view of the plurality of reeds per note, and of the ease of octave, as well as fundamental, oscillation development in translation from each reed, it is not necessary to rely on a large harmonic development in the reed vibration itself. Rather it is preferable that this vibration be of the aimplest mode conveniently attainable. 1 accordingly prefer, in the usual operation of voicing each reed, to do so in a manner most conducive to a simple vibrational mode; the reed configuration shown in Figure 2, while possibly not at once ideal for reeds of all sizes and types, is nevertheless intended to represent a reed voiced in the described manner. I further prefer to employ for vibrating the reeds a relatively small fiow of air, or small suction-i. e., as small as is consistent with dependable reed vibration and reasonably promptness of response; this of course has the effect of reducing harmonic development in the reed vibration. Again, I prefer to place the top and bottom electrodes progressively further from It frequently happens, and is particularly likely if the practise last mentioned is followed, that the amplitude of oscillations translated from the .lower frequency reeds is somewhat too small relative to that from the high frequency reedsin other words, a progressive decrease of efiiciency may be observed with descending note frequency. While this may be counteracted by progressively more weakly voicing the higher note reeds, this is a rather inefficient and otherwise somewhat unsatisfactory practise. It is of course also possible to increase the area of the electrodes adjacent the lower note reeds, as by providing extra electrode screws immediately adjacent the regular ones. .In Figure 5, however, I have illustrated another way of coping with this problem; this consists in the application of extra high voltages across the capacities-e. g., to the electrodesassociated with the low note reeds, progressively reducing these voltages for the higher note reeds. This may of course be done in the case of each electrode strip, and has been illustrated in Figure with the therein appearing strip 39 (for the electrode screws 29) The connection of the potential-applying conductor 69 is shown made to the low-note end of that strip; the latter is provided with a plurality of breaks or discontinuities 16; across each break is connected a resistance H; and from the high-note extremity of the strip to ground is connected the resistance 11''. The extra high voltage is applied by 69 in full strength to the lowest-note electrodes; but the potentiometric action of the several resistances 11 together with the resistance 11" progressively reduces the voltage received by the higher-note electrodes. The smoothness of the action from note to note is of course a function of the completeness of distribution of the resistances H (or of the number of breaks (6), which may be established as desired; perfect smoothness is not at all necessary, however, since instrument voicing may be relied on to smooth out quite wide residual irregularities.

Figure 1a illustrates the hereinabove mentioned use of a super-audible alternating carrier, instead of a steady or direct, voltage for application in the first instance across the reed-to-electrode capacities. A generator 14 of the carrier frequency oscillations is substituted for the battery 63 of Figure 1, and a mid-point ground is indicated by the shunting across the generator of a resistance 15 with its mid-point grounded; the circuit of Figure 5 also omits the low-pass filters H. Otherwise it is similar to the corresponding portion of Figure 1, for which it may optionally be substituted. It is to be understood that, with the circuit of Figure 1a in use, the electrical input to tube 53 will comprise carrier frequency oscillations modulated by the desired oscillations, and this tube is therefore operated'as a demodulator. To change its parameters to effect this action instead of simple amplification, its bias resistance 51 may be varied upwardly to a relatively high value. It is particularly desirable, with the potentiometers ll", 19", etc., and of the re-' sistances 13", 13, 13, be kept relatively low so that the entire control circuit is of relatively low impedanceotherwise various additional shielding precautions may be required. While there are obvious distinctions in underlying mode of carrier frequency operation from mode of direct voltage operation, and while the precise action of the control system is somewhat modified, it is believed that for the purposes of the instant application both forms of the instrument represent specific embodiments of one generic instrument.

In Figure 6 I show a modified form of instrument wherein either direct or carrier voltages may be applied in the first instance across the capacities, the use of the former being preferred and illustrated; and wherein voltages of fixed relative characteristics (for example, mutually similar) are maintained in the several capacities to produce a plurality of series of oscillations of fixed relative characteristics, the oscillations of the several series being thereafter controlled in respect of amplitude and phase before their combination. There are also incorporated in this illustrated instrument of Figure 6 further features which will be described hereinafter.

While the mechanical arrangement of the instrument may be' identical with that of Figure 1, I have shown a somewhat modified one by way of alternative illustration. The base is designated as 2a,, in view of a somewhat deeper dimension, and the reed-housings l4, l4, l4"- each as heretofore-are assembled directly to the base (through the vibration insulation l5, l5, l5") instead of to a channel-block as in Figure 1. The housing-ducts l9, l9, I9" for each one note respectively communicate with three apertures 4a, 4a, 4a in base 2a in frontand-back alignment with each other, the structural portion of Figure 6 being in general a section taken through a key I (a white key) and these three apertures for that note. The valveopening push-rods I0 are provided as before,

carrier frequency operation of the instrument,

but the valves (5a) are made longer so that each simultaneously controls the flow of air through a respective group of three apertures 4ala'-4a". The several portions of the valve are otherwise similar to those in Figure 1, and have been similarly designated but with the addition of the letter a. The suction chest has been designated as 3a. A closed removable cover 43a is provided over at least the reed-housings, having been only fractionally illustrated in Figure 6; this cover may be provided interiorly with electrostatic and acoustic shieldings 45a and 46a respectively, as was the cover in Figure l. The electrostatic cover shielding 45a may make contact with the grounded electrostatic shielding 50a provided on top of base 20. underneath the reed-housings (and of course apertured to correspond with base 2a).

In this figure each of the four top electrode strips (38", 38", 38' and 38) and each of the four bottom electrode strips (39", 39, 39' and 39) has been shown connected to one extremity of a respective work circuit%-i. e., of a respective resistance designated by a number higher by 60 than the strip number-the other extremity of which is grounded. (It will of course be understood that all the electrode strips-that is to say, including the strips 4i 4 l 4lmay be similarly treated, the restriction of the illustration being in the interest of clarity.) These resistances are each of high value, and may form the changestabilizing means for the reed-electrode capacities; the reeds being established, by circuitsand connections hereinafter more particularly described, at mutually similar direct potential differences from ground. It will therefore be understood that across the several work circuits will be respectively produced a like plurality of series of oscillations, of fixed relative characteristics. While a variety of means are available for combining these series of oscillations from the work circuits in various amplitude and phase relationships, I have illustrated an arrangement wherein each series is applied to the grid of a respective amplifying tube (designated in each case by a number lower by 10 than the respective work circuit). The tubes may have cathodes (heated in any suitable manner) paralleled and connected to ground through by-passed bias resistor 51a, the work circuits as illustrated forming the grid leaks for the tubes. To the output circuits of the tubes (whichmay include the common plate current source or battery 58a) is connected a timbre control system 8|! which may for example be of the form illustrated in Figure 2 of U. 8. Letters Patent No. 1,929,032 issued October 3, 1933, to myself and Charles T. Jacobs, and therein described. The output of the timbre control system may be led by leads 8! to the amplifier 54 and loudspeaker 55 as in Figure 1, the amplifier being as before provided with the volume control 59 responsive to pedal 68.

Because of the relatively high impedances separating the several strips 38", 39", etc., from ground, it is important to provide good electrostatic shielding of these strips, and of the work circuits and tubes immediately connected therewith, from stray fields, and like element from like element. Accordingly I have schematically shown the electrostatic shielding 45:: extended around these elements, and further electrostatic shielding 82 (connected with Mic) interposed between successive tubes, work circuits and leads thereto. Between strips which are mutually close-e. g., between 39" and 39" and between 39'' and 39""-I have structurally shown shielding strips 83, connected with shielding 82.

The instrument of Figure 6 has been illustrated as including means for automatically regulating the amplitude-time characteristics, or envelopes, of its tones; this is done by automatically varying the efliciency of translation of the reed vibrations or, still more specifically expressed, .by automatically varying the voltages applied in the first instance across the reedelectrode capacities-i. e., the direct potentials applied to the reeds. The circuits for accomplishing this result may for example be in general like those shown in U. S. Letters Patent No.

1,915,859, issued June 27, 1933, to myself and Charles T. Jacobs; the reed taking the place of the string vibrator, and a suitable key-operated switch taking the place of the piano back-check switch, illustrated in that patent. While in its broader aspects this arrangement is obviously not new, some peculiar advantages are obtained by its use in connection with air-blown reeds.

Among them may be mentioned the ability, by

making the rise of voltage on the reeds sufllciently slow, to equalize the rates of rise of the tone components produced by different pitched reeds (both as to components of a single note, and as to different note components)rates which with air-controlled reeds inherently tend to be less rapid the lower the reed pitch; and the the several screws 25' and 25".

smooth rise to a maximum (as a result of the smooth reed vibration inception) followed by a smooth decay to a low or zero value (produced by the translation efllciency or voltage change). The circuit arrangement under discussion may also, as is hereinafter set forth in detail, be put to the distinct use of completely determining the beginning and ending of the tones, all the reeds being maintained in-continuous vibration.

To incorporate this circuit arrangement in the instrument, it is necessary that the reeds no longer be connected together. Accordingly the strip 35, which interconnected the reeds in reedhousing It, is omitted, and replaced by a plurality of threaded bushings 852:, 8511 (one for each screw 25) or by any other convenient means of connection to the individual screws 25. Similarly the strips 35' and 35" on the housings l4 and M" are omitted and respectively replaced by bushings 851:, 8531' and 85m", 851/", individual to This has been indicated in Figure 6 by showing in broken crosssection the bushings 85x, 85:2, 852:", with respective screws 25x, 25:12, 25m" (the sumx :i: being included to denote correspondence with the white key is appearing in cross-section); and in elevation therebeyond the bushings 85y, 8511, 8511", with respective screws 25y, 25y, 2511" (the sufiix 1 denoting correspondence with the back key iy ap in elevation immediately beyond the white key Ix).

An individual conductor is connected to the three bushings 85, 85', 85" for each individual note-shown as 86.1: for 85x85x'85:c", and as 8611 for 85y85y85y"-it being understood that one such conductor per note is provided. Inserted in each conductor is a time-delay system (e. g., 90:: and 901 each system being illustrated as comprising two tandemed filter circuits each of series resistance 9h: or Sly and condenser 92:: or 921/ shunted to ground. Each conductor (e. g., 861:, 86y) runs from the pole (e. g., 930:, 931/) of a respective switch 93' under the key for the respective note; the pole may be a strip of metal or of conductive paint on the bottom of the key. The contact against which the switches close-i. e., upon key depression-,-

ability to obtain envelopes which comprise a is a thin strip 8d of conductive material, resting on top of a metal strip 84", both strips being continuous or common for all the notes. The strip Bl preferably is soft and characterized by appreciable transverse electrical resistance, which preferably varies with transverse pressure; it may comprise a strip of felt impregnated with conductive material, as by treatment in a colloidal graphite solution such as is available under the trade name of Aquadag." The strips 84'84" may of course form the down-stop for the keys. The strip 84" is connected, by a single conductor, to a source of direct potential-preferably adjustable--illustrated as the variable contact 94 of a potentiometer 6M shunted across a battery or other high voltage source 423, one extremity of which is grounded. It will be understood that upon depression of any key not only will the valve 541 be opened to vibrate the reeds associated with that key, but also those reeds will be connected through the associated conductor '88:: or 86y, time-delay system. 99:: or 903 and now-closed switch 53', to the potential of contact 94; assuming the reed to be initially of other potential, its potential will change to the contact 94 potential-but, by virtue of the time delay system, this change will take place not abruptly,

but at a rate predetermined by the constants c! that system.

were the sole conductive connection to the reeds the one just described, the reeds of any note would retain the contact 94 potential indefinitely after release of their associated key, or until second-order leakage eilects had gradually altered their potential. To invest them with a normal potential, from which only depression of r the associated key will serve to change them and to which they will return upon key release, their conductors 06 are connected, preferably on the switch sides of the I time-delay systems, first through respective resistances (e. g., l'lx, 011;) and then through a common conductor to variable contact 95 on potentiometer 425 also shunting the voltage source 423. If, as shown, contacts 94 and 95 are at substantially corresponding points on their respective potentiometers, the reed potentials will remain essentially constant with respect to ground, and the instrument will function essentially as though the entire envelope-regulating system were omitted.

If, however, contact 95 be moved to the ground end of its potentiometer, the reed potentials will normally be that of ground; upon depression of a key the potentials of the associated reeds will rise at the predetermined rate to a potential cs tablished by contact 94 (and also influenced by upon by virtue of their resistance 811: or 8111 they will return to ground potential at another predetermined (usually slightly slower) rate. of potential rise may for example be made uniform for the diflerent notes, and of the order of slowness of the rate of slowest reed vibration amplitude rise upon valve opening; this (coupled with the minute delay of potential rise inception resulting from the fact that the valve begins to open as soon as key depression is begun whereas the potential does not begin to change until key depression is completed) several fairly satisfactorily to equalize the rates of output tone rise over the note range-e. g., between bass and treble.

The rate More perfect equalization may be eifected, however, by adjusting the several time-delay systems to make the rate of potential rise quite rapid for the lowest frequency reeds, and progressively more slow for the higher frequency reeds; by.

Still again, the contact 95 may be adjusted for substantially full potential as shown, and the contact 94 to low or ground potential; in this case the reed potentials will be normally high; but upon depression of a key the potentials of the assoelated reeds will fall to low or zero value at the predetermined rate, there remaining until key release. The vibration curve rising and the translation efiiciency curve falling, the tone at first gradually rises to some peak amplitude and then falls to a low or zero amplitude, which it retains until key release; this produces a unique and musically interesting effect. Various other adjustments of the two contacts 94 and 95 are of course possible, for the production of still other or modifled effects.

In Figure 6 I have shown arrangements whereby if desired all the reeds may be kept in a state of continuous vibration, the tone production being entirely controlled by the automatic enveloperegulating system Just described. The arrangements comprise means operable to hold open simultaneously all the valves Ia. Thus depending from the forward end of each valve strip to may be provided an L-shaped hook I25; and a strip I25 may be provided transversely of the instrument, having its forward edge hinged to the front of the suction-chest 3a and its rear edge portion arranged to engage the hooks I25. Normally this strip is prevented from pressing downwardly on the hooks by one or more upward biasing springs I21; but it may be pulled downward, against the force of these springs and opening all the valves, by the handle I29 on wire I28 secured to the bottom of the strip-and locked in valveopening position as by engagement of hook I30 in the wire with an appropriate fixed pin I3 I Thus all the reeds are placed in continuous vibration.

The manner in which the envelope-regulating system functions to clintrohthe tone production will be entirely obvious in'viewoi the foregoing discussion of that system-it being understood, of course, that for instant purposes the contact I23 will be adjusted to ground potential and the contact I22 to a high potential. It may be noted that with this mode of operation of the instrument there are of especial importance the vibration insulations I5, I5, I5"; the acoustic shielding 46:13 the acoustic shielding and inter-note de-coupling provided by the cell extension struc tures 33, 33', 33" the inter-note de-coupling provided by the duct linings 32; and in general all conveniently available measures for suppressing acoustic output from the instrument and internote reed couplings. It is also to be noted that with this mode of operation the degree of suction in the chest 3a may advantageously be established at the minimum which will dependably maintain vibration of all the reeds, no longer being required to be of that ordinarily higher minimum which insures reasonably prompt reed response upon valve opening; this lower degree of suction, and hence more feeble air stream past each reed, results in smaller harmonic development and, since the vibration amplitudes are lower, in more truly linear translation by each of the top and bottom electrodes.

I have hereinabove describedthe instrument of Figure 6 as a complete one-manual instrument. of courseI may associate. therewithorie or more further manuals; and the association therewith of one further manual has been illustrated in the figure-a particular purpose of this illustration being to show an inter-manual coupling arrangement, particularly useful when the instrument is operated, as last above described, with all reeds continuously vibrating. To simplify the illustration of the second manual, a dash-dot enclosure I00 has been drawn around apparatus which may be peculiar to the first' manual; this may for example comprise the entire instrument as so far described with the exception of amplifier .54, volume control and pedal 59 and Gil, and loudspeaker 55; an extending portion of base 2a and top portion of push-rods I0, with keys I and associated switches 93'; and battery 423 with potentiometers 424 and 425. Apparatus for the second manual duplicating that in the enclosure I00 has been schematically illustrated by a second dash-dot enclosure 200, extending from which is the base portion IBM; in the base are freely positioned the valve push-rods H0; and on the base are assembled the second manual keys EM, having associated therewith switches I93 similar to, and with parts designated by numbers higher by 100 than those of, the switches 93' of the first manual. From the poles i932, I93 of the switches I93 there may extend to the second manual reeds (of course through time-delay systems and otherwise in manner entirely analogous to conductors 86 of the first manual) conductors shown as i861: for that second-manual white key which appears in cross-section, and as i851; for the elevationally appearing adjacent black key. These conductors are also connected first through the respective resistances iB'Iz, i871! and then through a common conductor and switch dti to a second and independently variablecontact 895 on potentiometer M5. The metal strip E83" which forms a portion of the switches I93 is connected directly to a second and independently variable contact I94 on the potentiometer 82%.

From the timbre control 580 schematically indicated within the enclosure 200 a pair of conductors i8i lead to the amplifier 55, wherein the single-throw, multi-pole switch 432, which may be closed to connect each one of the conductors 86s, 8611 with a respective conductor 8860:, i861 which corresponds with it-i. e., which is for the same note, its upper ocative, its sub-octave, or the like. Thus as illustrated, each of these conductors has connected thereto a lead (e. g., 962: to 852:, 9611 to 861/); correspondingly each conductor I861; i861 has connected thereto a corresponding lead NM, 8961 and the several conductors 982:, 9611 on the one hand, and 8961:, i98

on the other hand, respectively lead to the oppo-' site sides of the switch 632, by the closing of which mutually corresponding ones may be connected together. The switch 43! abovementioned may be a single-pole, double-throw switch coupled with switch 832, so that when the latter is closed the resistances i8lr, i811 are disconnected from their potentiometer contact 5 95 (peculiar to the second manual) and connected, together with the resistances 812:, My, to the potentiometer contact 95. This results in then maintaining at the same potential (in this mode of operaiton, desirably ground potential) all those reeds, in

.both manuals, whose keys are not depressed. It

will be appreciated that now, upon depression of either of two mutually corresponding keys in the respective manuals, the same output tone will be produced-and that it will represent the true superimposition of the tones separately available from the two manuals with whatever timbre control adjustments may be effected in each.

It is to be stressed that with this system of superimposition of a plurality of tones, a true choir effect is produced; for the several tones are derived from independent and mutually uncoupled sets of vibrators, between which there are oscillations from the two manuals may be combound to exist those minute and random (1. e.,

different for diflerent notes) tuning differences which in conventional acoustic organ performance are probably almost wholly responsible for the cherished sensation of plurality of tone sources. And of course this true choir effect is present in uncoupled simultaneous operation of the two manuals.

It will be understood that I intend herein to make no unnecessary distinction between suction or pressure operation of the reeds, and that in general I have used such terms as degree of suction and pressure in a wholly synonymous sense. Indeed, as to various individual aspects of my invention, I intend no unnecessary Linitation of the vibrators to reeds, or of other elements or portions to the precise forms shown and described; rather I intend in the following claims to express my invention, and all its novel combinations, sub-combinations and elements, as broadly as the state of the art will permit. No claims are made herein, however, to the broad aspect of translation of the reed vibrations by one or more translating means associated with the reed (either generally, or by electrostatic means in particular, or with differential control over the several devices associated with one reed) orapparatus therefor; or to a reed block formed of insulating material, or carrying an electrode; or to an electrode in spaced relation to the edge portion of the reed; or to any other of the novel features disclosed in my co-pending application, Serial No. 758,155, above mentioned.

I claim:

1. In a musical instrument including a reed housing: the combination of an apertured reedblock adapted to be removably inserted in said housing; a. tuned reed secured to said block; and

conductive means carried by said housing and' I adapted for automatic electrical connection with said reed upon insertion of said block into said housing. 1

2. In a musical instrument including a reed housing: the combination of an apertured reedably inserted in said housing; a reed secured to said block; an electrode carried by said housing and extending, when said block is inserted in said housing, into said aperture;.said block being provided with a channel adapted to clear said electrode during removal of said block.

4. A musical instrument having a plurality of mutually coupled reeds substantially tuned to harmonically related frequencies, and pneumatic means for simultaneously vibrating said reeds,

the coupling of said reeds being so close that they lock in integral frequency relationship.

5. In a musical instrument: the combination of a reed block provided with an aperture, and a plurality of substantially harmonically tuned reeds secured to said block and adapted to vibrate in said one aperture.

6. In a musical instrument including an apertured reed-block: the combination of a reed-base secured to said block; and a plurality of substantially harmonically tuned reeds formed from said one base. a

7. In a musical instrument having a reed housing provided with a plurality of cells: the combination or means for passing air streams through said cells; and a plurality of substantially harmonically tuned reeds positioned in each one of said cells for simultaneous vibration by the airstream therethrough.

8. In a musical instrument having a plurality oIreeds arranged for the production 01' various notes: the combination or apneumatic system for vibrating said reeds; and means associated with said system for suppressing coupling between the reeds of respectively diflerent notes.

9. In a musical instrument including a plu rality of reeds arranged for the production of various notes: a pneumatic system including means providing a plurality of air paths in which said reeds are respectively positioned for vibration, at least portions of the inner surfaces of said path-providing means being of sound-absorptive material.

10. In a musical instrument including a plurality of reeds arranged for the production of various notes: the combination of a pneumatic system including means providing a plurality of air paths; in which said reeds are respectively positioned for vibration; and sound absorptive but air-porous means associated with said pathproviding means to cover extremities of said paths.

11. In a musical instrument having a plurality of progressively tuned vibrators: the combination of a plurality of electrodes each forming a capacity with a respective one of said vibrators; and means for impressing voltages across said capacities, said impressed voltages being progressively reduced across the capacities associated with progressively higher frequency vibrators.

12. In a musical instrument having a plurality'ot electrically paralleled tuned vibrators: the combination of a plurality of paralleled electrodes each in spaced relationship to a respective said vibrator, said electrodes forming a single capacity with said vibrators; switch means for app y ng various direct voltages across said capacity; and low-pass filter means interposed between said switch means and said capacity.

13. In a musical instrument having a plural ity of sources of electric oscillations: the combination of means, including a number of selectively operable switches, for eifecting a like number of harmonically diilerent predetermined combinations of oscillations from said sources; and means connected with said switches for rendering substantially cumulative, upon simultaneous operation of any plurality of said switches, both the harmonic structures and the amplitudes of the oscillation combinations effected by separate operation of each switch of such plurality.

14. A musical instrument having a plurality of depressible playing keys and switches associated with said keys, said switches comprising poles rmpectively carried on the bottom surfaces of said keys and a conductive strip extending transversely of and underneath all of said keys, said strip forming a downstop for said keys.

15. In a musical instrument including a tuned reed and pneumatic means for vibrating said reed: the combination of a key controlling said pneumatic means; an electrode forming a capacity with said reed; means for impressing voltage across said capacity; means associated with said key iorcontrolling said voltage impressing 16. In a musical instrument including a tuned,

reed arranged for pneumatic excitation: the combination of a key depressible to cause such excitation; means, normally 0! given efllciency, associated with said reed for translating its vibratlons into electric oscillations; means responsive to key depression for reducing said efllciency; and time-delay means included in said reducing means.

17. In a musical instrument having a plurality of progressively tuned reeds arranged for pneumatic excitation and for the production of progressive musical notes: the combination of a plurality of keys depressible to cause such excitation of the respective said reeds; means associated with said reeds for translating their vibrations into electric oscillations, said means being maintained normally at zero eillciency; means responsive to depression of said keys for producing a rise of said translating means eillciency as to the respective needs; and means for rendering said eii'lciency rise progressively more gradual tor progressively higher frequency reeds.

18. In an organ including a plurality of manuals: the combination of a plurality of groups of reeds vibrationally responsive to said manuals respectively; means associated with each group of reeds for translating electric oscillations from their vibrations; and a plurality of means respectively connected with said translating means for independently controlling the amplitude-time characteristics of the oscillations produced by each group of reeds.

19. An organ comprising two manuals of keys; two groups, responsive to said manuals respectively, of reeds and means associated therewith for translating electric oscillations from their vibrations; and electrical means associated with said translating means and selectively operable to couple said manuals together.

20. A musical instrument comprising a plurality of progressively tuned reeds; an individual mechanico-electric translating system, responsive to electrical actuation, for each note, for translating reed vibration into electric oscillations; and means for operating said instrument comprising means for maintaining continuous vibration of all said reeds, a plurality of playing keys corresponding to said translating systems, and means for actuating said translating systems only in accordance with the manipulation of said keys.

21. In a musical instrument having a plurality of tuned reeds arranged for pneumatic excitation: the combination of a plurality of valves selectively openable to cause such excitation of the respective said reeds; and means associated with said valves and operable at will to open simultaneously all said valves.

22. In a musical instrument having a plurality of progressively tuned vibrators: the combination of a plurality of electrodes each forming a capacity with a respective one ofsaid vibrators; and means for impressing voltages across said capacities, the impressed voltages varying progressively across the capacities associated with progressively more extreme-frequency vibrators.

23. In a musical instrument having a plurality of progressively tuned vibrators: the combination of a plurality of keys depressible to cause excitation of the respective said vibrators; means associated with said vibrators for translating and means inciudedinsaid rise-producing means their vibrations into electric oscillations. said for rendering said efliciency rise progressively means being maintained normally at zero eflimore gradual for progressively more extremeciency; means responsive to depression of said frequency vibrators.

keys for producing a rise of said translating 5 means efliciency as to the respective vibrators; BENJAMIN F. MIESSNER.

CERTIFICATE or CORRECT-ION; Patent No. 2,257,10 April 1, 19m.

BENJAII-m F. HIESSNER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, sec-- ond 001mm,- line 61, for "overshadow" read -overshadows; page 9, first column, lineup, for several read -s erves--; page 10, first column, line 112, for "ocative" read -octave--; page 11, second colnmn, line 21;, claim 17, for "needs" read -reeds-'-; and that the said Letters Patent should be read with this correction therein that the .same may conform to the record of the case in the Patent Office.

p Signed. and sealed this 20th day of January, A. D. 191m.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECT-I031 Patent No. 2,257,105. April 1, 19m.

BENJAMIN F. MIESSNER.

It is hereby certified .that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, sec- 0nd col umn; line 61, for "overshadow" read "--oversha.dows--; page 9, first column, line M4, for "several" read serves-; page 10, first column, line 142, for "ocative" read --octave--; pigell, second colnnm, line 21!, claim 17, for "needs" read --reeds--; and that the said Letters Patent should be read with this correction therein that the .same may conform to the record of the case in the Patent Office.

' Signed and sealed this 20th day of January, A. b. 191m.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

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