US2966821A - Electronic piano - Google Patents

Description

Jan. 3, 1961 B. F. MIEssNER 2,966,821

ELECTRONIC PIANO Filed June 26, 1957 ,l -2 4f, 45,1 R *EH-4 INVENTOR nited States Fatent 'a ELECTRONIC PIANO Benjamin F. Miessner, Harding Township, Morris County, NJ., assigner, by mesne assignments, to The Wurlitzer Company, Chicago, Ill., a corporation of Ohio Filed June 26, 1957, ser. No. 668,061

11 claims. (ci. sti-1.14)

This invention relates to electronic musical instruments, and more particularly to such instruments for the production of pianistic tones.

In other co-pending applications of mine (eg, Serial No. 169,714, now abandoned led June 22, 1950; Serial No. 255,383, now Patent No. 2,919,616 filed November 8, 1951; and Serial No. 485,471, now abandoned filed February l, 1955), as Well as in U.S. Patent No. 2,672,- 781 issued on another application of mine, I have disclosed, for the production of a pianistic tone, an impulseexcited fixed-free reed with an adjacent electric translation pick-up vibratorily passed by the vibrating reed. In those applications I have brought out the ability of a suitable arrangement of this character to produce, from the fundamental vibration of the reed, electric oscillations of corresponding fundamental frequency but also containing a series of upper partials harmonically related thereto-translation of inharmonic components correspending in frequency to the lower ones of the upper partials at which the reed inherently tends to vibrate (all of which are normally inharmonic) being suitably eliminated, one step in such elimination being for example a placement of the pick-up at a position longitudinally of the reed which is nodal for the second-partial vibration. In Serial No. 485,471 I have discussed the problem of the tendency of the tone, in the absence of appropriate measures, to lack the initial high decrement, immediately following the instant of impulse excitation, which is so typical of piano tone, and I have explained how a positioning of the pick-up alongside an edge of the reed intermediate its extremities (rather than, for example, at the end of the reed) will minimize this tendency. Also in Serial No. 485,471 I disclosed a manner of not merely eliminating this tendency, but of actually reversing it to greatly heighten the initial decrement.

T he present invention is directed to an improved manner of minimizing the lack of initial high decrement, and of reversing it to heighten the initial decrement without reliance on the full technique disclosed for the latter purpose in Serial No. 485,471.

It is an object of my invention to achieve an initial decrement in musical tones, produced by electrical translation from the vibrations of impulsively excited fixed-free reeds, which frequently are characterized lby slight initial increments.

It is an object to achieve this result in a very simple manner, and without additional elements or additional :manufacturing complexities over those usually involved.

It is an object generally to improve the initial characteristics of such tones.

It is an object to improve the simulation, by an instrument employing impulsively excited fixed-free reeds electrically translated from, of a conventional piano.

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

In the description of my invention hereinafter set forth 'reference' is had to the accompanying drawings,'in which 2,966,821' Patented Jan. 3, 196i Figure 1 is an elevational View of a fixed-free reed in rest position, with an associated pick-up;

Figure la is a plan view of the structure of Figure l;

Figure 2 is a view similar to Figure l, but illustrating the reed in a position which involves substantial displacements from rest position both at its fundamental or rstpartial vibration mode and at its second-partial mode;

Figure 3 is a view similar to Figure l, but illustrating the reed in a position which involves negligible displacement from rest position at its fundamental mode but substantial displacement therefrom at its second-partial mode;

Figure 4 is an elevational view of a structure similar to that of earlier figures but with a pick-up embodying my present invention, the reed itself being illustrated in a position analogous to that of the reed in Figure 3;

Figure 4a is a plan View of the structure of Figure 4;

Figure 5 is a View similar to Figure 4 excepting that it illustrates a modified pick-up embodying the invention;

Figure 5a is a plan view of the structure of Figure 5;

Figure 6 is a view similar to Figure 4 excepting that it illustrates a further modified pick-up embodying my invention;

Figure 6a is a plan view of the structure of Figure 6.

Reference being had to Figures l and la, there will be seen a fixed-free reed 1 projecting horizontally from any suitable mounting base 2. The reed may be `arranged to be impulsively excited into vertical vibration, as by the provision of a hammer fractionally shown as 3, which may be propelled upwardly by any suitable hammer-actuating action (not shown) to strike the reed-for example at its longitudinal mid-point, which (for a uniform-crosssection unweighted reed) is a third-partial node, thus substantially eliminating any third-partial component from the ensuing vibration of the reed.v That vibration will of course be decadent-ie., will decrease progressively with time following the excitationbut with suitable base arrangements the rate of decay will be suitably low.

The pick-up 5 in Figures l and 1a is sho-wn as a Hat electrode, typically somewhat thicker than the reed and of a length (measured along the reed) many times that thickness, located alongside the reed in close spaced relation thereto and of course vibratorily passed by the reed during the reed's vibration; it may for example be folded over from the supporting stem 6, which is much more widely spaced from the reed. Longitudinally of the reed the pick-up is preferably positioned at--i.e., substantially straddling, or equi-extensive in each longitudinal direction from-the second-partial node of the reed (which for a uniform-cross-section unweighted reed is at Aapproximately 78/100 of the reed length `away from the fixed extremity). In the direction of reed vibration, or vertically, the piek-up may be displaced very slightly (as illustrated, downwardly) from the rest position of the reed, so that the maximum interception of the pick-ups eldby the reed (i.e., the maximum capacity, or exposure, of the reed to the pick-up) will occur when the reed is very slightly displaced (downwardly) in its fundamental mode from its rest position-under which circumstances the reed would still be essentially straight. insofar as vibration confined to that fundamental mode is concerned, typical maximum peak upward and downward vibratory excursions of the reed are indicated by the dash-dot lines U and D, respectively.

With the illustrated capacitative type of pick-upwhich, as is `now well understood, may be connected to a suitable electrical circuit (not shown) operating on a simple D.C. basis, or on an amplitude-modulating highfrequency or a frequency-modulating high-frequency basis-the oscillations translated by the systemfromlthe 'reed vibrations are functions of the capacity *between the reed and the pick-up. Speaking for convenience in terms of vibration of the reed in its fundamental mode, it will be understood that when the reed moves upwardly the capacity between it and the pick-up will progressively reduce; that as the reed moves downwardly from an upward excursion that capacity will progressively increase, reaching its original value when the reed reaches its rest position (in which it is illustrated in Figure 1); that as the reed continues to move downwardly that capacity will at the very first still further increase somewhat, to a maximum when the reed and pick-up are in alignment wit each other, and 'will then progressively decrease; and that as the reed moves upwardly from a downward excursion that capacity will progressively increase, reaching its abovementioned maximum when the reed and pick-up are again in alignment with each other, and will then decrease to reach its somewhat smaller original value as the reed reaches its rest position-whereupon the cycle will repeat itself recurrently, subject only to the minute amplitude reduction from cycle to cycle implicit in the decadent nature of the reeds vibration. The foregoing analysis of course assumes that the reed movement is of substantial amplitude, so that in its downward excursion it proceeds far beyond a position of alignment with the pick-up; the analysis readily shows that two similarly directed peaks per cycle are produced, and that these are separated by almost 180 degrees in the case of high-amplitude vibration. That separation will reduce as the amplitude reduces; when the reducing amplitude has reached a value only suiicient (at the peak of downward excursion) to align the reed with the pick-up that separation will have reached zero-after which there will be in each cycle only one peak in the direction in which there formerly were two.

lt is well understood that an intra-cyclic departure from pure sinusoidal character, if repeated from cycle to cycle (subject to no more than the minute shifts from each cycle to the next mentioned above as an incident of the gradual decay of the vibration amplitude) gives rise to the generation of partials which are limited to integral multiples in frequency, or true harmonics, of the fundamental. From this it will in turn be understood that the translated oscillations (being functions of the described capacity variations) will contain a series of upper partials harmonically related to the fundamental, derived from the fundamental vibration through the action of the pick-up. lt will at the same time be understood that as the amplitude gradually decays (and the departure from true sinusoidal character gradually decreases) the series of harmonic upper partials in the translated oscillations will diminish in composite magnitude (i.e., amplitude relative to the amplitude of the fundamental).

For convenience the operation has thus far been described` in terms appropriate to the supposititious case of reed vibration occurring at the reeds fundamental mode only. Actually, of course, the impulse excitation results in vibration of the reed at its upper-partial modes as well, particularly that of its second partial (the third in the typical structure above described being substantially eliminated as mentioned above, and the fourth and higher ones being ordinarily of progressively diminishing and usually negligible amplitudes). The second-partial vibration may be considered as superimposed on the fundamental vibration-but not in any fixed phase relationship thereto, which in the ordinary case it is precluded from occupying in view of the non-integral ratio between the frequencies of the two; that ratio is 6.28 for the ordinary case of a uniform-cross-section unweighted reed.

The presence of the higher-partial vibrations superimposed on the fundamental has two effects which have been discussed in one or more of the copending applications mentioned above. One of these is the vibration of the reed portion influencing the pick-up, unless an appropriate counteractive measure be taken, at the secondvibration-partial frequency, resulting in translation of an oscillation component corresponding in frequency to the second-partial vibration and therefore normally inharmonic to the fundamental; the counteractive to this undesirable effect, and thus to its result, which is employed in the here-illustrated structure is the placement of the pick-up longitudinally of the reed at the second-partial node. The other of these effects is the dynamic shortening of the reed, relative to the length it would have if vibrating at its fundamental frequency only, caused by the curvatures of the reed incident to its higher- (and particularly second) partial vibration, which shortening is at a maximum in the very initial part of the tone and would then seriously decrease the efficiency of translation by a pick-up located beyond the free end of the reed; the counteractive to this undesirable result which is employed in the here-illustrated structure is the placement of the pick-up at the side of the reed so that the shortening has no influence on the reed-to-pick-up spacing, These two counteractives are mutually compatible, and structure embodying them has been claimed in my co-pending application Serial No. 485,471 abovementioned.

I have discovered, however, that the presence of the higher- (and particularly second) partial vibration superimposed on the fundamental has still another effect; like the dynamic shortening, its result in the absence of appropriate counteractive measures is a decrease of the translation efficiency during the very initial part of the tone. This effect is a temporary substantial angular deviation of the plane of the portion of the reed which passes the pick-up about the plane which would be established for that portion by pure fundamental vibration. The nature of this deviation, the way in which it influences the translation eciency, and appropriate counteractive measures may now be described with reference particular ly to Figures 2 and 3.

Figure 2 (in which the dash-dot line R indicates the center line of the rest position of the reed) illustrates the reed in a configuration typical of a maximum peak upward fundamental vibratory excursion, with a maximum peak free-end-downward second-partial excursion superimposed thereon-a mutual relationship of excursions which tends to occur at the time of excitation, and which substantially recurs (at progressively diminishing peak amplitudes) at intervals, each of a number of fundamental cycles, determined by the second-to-first-partial frequency ratio. Figure 3 in turn illustrates the reed in a configuration typical of the minute downward fundamental excursion (from rest position) which would be necessary to bring the reed into alignment with, or into maximum exposure to, the pick-up (which, if occurring without a second-partial excursion superimposed thereon, would bring the free-end portion of the reed to the position dottedly illustrated as 1 and having the center line C'), with a substantially maximum peak free-end-upward second-partial excursion superimposed thereon-a mutual relationship of excursions which will occur extremely early following excitation and will also substantially recur (at progressively diminishing peak amplitudes) at intervals, each of a number of fundamental cycles, mentioned above. And within the maxima (and again subject to progressively diminishing peak amplitudes) all other possible congurations resulting from combinations of peak and less-than-peak fundamental excursions with peak and less-than-peak second-partial excursions will occur and substantially recur-the particular combinations shown in Figures 2 and 3 having been chosen simply for convenience in description.

Consider the initial second or two immediately following a substantial impulse excitation of the reed, and during this interval consider the instants (which occur twice in each fundamental cycle) when the longitudinal center line of the reed is intersected by the transverse horizontal center vline of the pick-up (Le. in Figure 3, a line through the center of electrode 5 perpendicular, which may b: considered the fullest juxtaposition of reed with pick-up;

. Ato the sheet of the drawing) Figure 3 illustrates one of those instants. From what has been said above it will be understood that in the series of those instants the plane of the portion of the reed passing the pick-up will have essentially all possible angular deviations from the plane of that portion established by pure fundamental vibration (i.e., from the substantially horizontal plane approximately indicated by the dotted center line C' up to some maximum angle of deviation typically illustrated for one direction of deviation in Figure 3, and in each of two possible directions of deviation. In other words, in several of those instants (not immediately successive) the portion of the reed passing the pick-up will be substantially as illustrated in Figure 3; in others (not immediately successive) it will have a slightly smaller, in others (not immediately successive) it will have a substantially smaller, and in others` (not immediately successive) it will have a very much smaller deviation from C in the same direction; in several of those instants (not immediately successive) it will have substantially no inclination to Cand so on (in a reverse descriptive sequence) through a range of inclinations in the opposite direction about C up to a maximum quantitatively similar to that shown in Figure 3.

At those of the instants mentioned above when the portio-n of the reed passing the'pick-up has substantially no inclination to C', the magnitudes of the resulting similarly directed oscillation peaks produced as early above described will be essentially as great as they would have been had the vibration of the reed been confined to its fundamental mode only. But at those of the instants when that reed portion has a maximum inclination to the line C (typically as illustrated in Figure 3, or of the same magnitude in the opposite direction) the capacity of reed to pick-up is very sharply reduced as a result of the fact that only a longitudinally restricted portion of the pick-up is fully juxtaposed to the reed; the resulting oscillation peaks are greatly tiattened-i.e., sharply restricted in magnitude, that restricted magnitude being spread out over somewhat more of a fundamental cycle. Similar effects, in varying intermediate degrees, occur at those of the instants when the reed portion has intermediate inclinations to C'. The average, and thus the net, effect on the similarly directed oscillation peaks is very substantial attening; the result of this in turn is a lowering ofthe efficiency of translation. This is especially true of the translation of fundamental-frequency oscillations; it is also totsome extent true of oscillations of twice that frequency, which are largely functions of the amplitudes of the two similarly directed oscillation peaks per cycle; and it is also to some extent true of the still higher harmonic components, which are functions of the sharpnesses of those peaks.

The rate of decay of the second-partial vibration is several times as great as that of the fundamental vibration, while the rates of still-higher-partiatl vibrations are still greater. Thus as the tone proceeds the oscillatory deviation discussed above rather rapidly dies away. The result of Vthis is a rather rapid increase of translation elticiency-aflecting the fundamental, its double-frequency, and still higher harmonic components. This increase, in 'its effect on the translated oscillations, opposes the effect of `the natural decrement of the fundamental vibrations and a typical result is an output tone whose fundamental, and even second harmonic partial, may have an early increment of amplitude instead of the desired decrement, and whose higher harmonic partials have lost the characteristic initial burst followed by very high decrement which they should have.

It is in the case of strong excitation, in the middle and especially in the lower register of instruments with typically dimensioned reeds and pick-ups, that this effect is particularly noticeable and particularly objectionable. I have observed that in these registers of such instruments the magniude of the maximum angular deviations disi6 cussed above-ie., of `such deviations immediately y-following a strong excitationis of the general order of one-fifth of a right angle (18 degrees) and sometimes more, while on the other hand it appears always to be' at least of the order of one-eighth of a right angle (approximately 1l degrees). By way of illustration, the angle of deviation in Figure 3 is very approximately onetifth of a right angle. v

Strictly speaking, of course, the portion of the reed passing the pick-up, especially when the above discussed angle of deviation is substantial, is slightly curved; in view of its limited length, however, it as a practical matter can be considered as planar. In the strict sense the angular deviation above discussed may be taken as referring to the deviation of a plane tangent to the stated reed portion.

l have found that it is possible so to shape or proportion the pick-up-speciically, its reed-ward face (i.e., its surface facing the path of vibration of the reed)-as. to eliminate, even for high maximum angular deviations, the undesirable result of temporary translation-efficiency decrease. This I accomplish by making that face at least substantially as fully exposed to the edge of the reed at the extremes of the oscillatory deviation as in the absence thereofor, in alternative phraseology, by making the longitudinal extent of the reed edge exposed to the pick-up when the reed is most fully juxtaposed to the pickup at least substantially as great at the extremes of the oscillatory deviation as in the absence thereof. More specifically, it may be accomplished by limiting the effective extent of that face in the direction of reed length to not more than the product of the effective extent o-f that face in the direction of reed vibration by the cotangent of the maximum angle of deviation.

Figure 4, which shows a reed similar to that ofFigure 3 and similarly configured (i.e., to a maximum angular deviation of the order of one-fifth of a right angle, or 18 degrees) illustrates a pick-up electrode 45 having a rectangular reed-ward face 45 of which the dimension or effective extent in the direction of reed length (i.e., horizontally) is limited to 3 times its dimension or effective length in the direction of reed vibration (i.e., vertically)-the cotangent of 18 degrees being minutely more than 3. Figure 4 illustrates a condition of lfullest juxtaposition of reed with pick-up (since the longitudinal center line of the reed would be intersected by the transverse horizontal center line of the pick-up electrode 45), and specifically such a condition obtaining while the reed portion passing the pick-up has its maximum or extreme deviation of some 18 degrees. It will`be observed'that the longitudinal extent of the reed edge exposed to the pick-up is (neglecting minute corner effects) the diagonal of the rectangular pick-up face 45'; clearly this is not only as great as, but is somewhat greater than, the longitudinal extent of the reed edge exposed to thepick-up in the absence of the angular deviationwhich extent would be almost precisely the horizontal dimension of the face 4S. Conversely, of course, the pick-up face is exposed along its diagonal to the reed; clearly this is not only as full exposure as, but is somewhat fuller exposure than, the exposure ofthe pick-up to the reed in the absence of the angular deviationwhich latter exposure would be simply along a substantially horizontal center path across the face 45.

It will, then, be appreciated that under conditions of maximum angular deviation-of theplane of the portion of the reed passing the pick-up from the plane which that portion would have in the absence of higher-partial vibration-the Figure 4 structure will yield oscillation peaks not flattened and attenuated, but actually slightly sharpened and increased, relative to those yielded in the absence of that deviation. As a result there is not any decrease, but instead actually a minute increase, of the translation efficiency during the initial period following strong excitation.

The limitation of effective extent in the direction of reed length need not be stopped at the stage shown in Figure 4. It may for example be carried to a degree such as shown in Figure 5, wherein the pick-up electrode appears as 55 and has a square reed-ward face 55'. yIn this case the effective extent in the direction of reed length is only a fraction of the maximum length which would be permitted bythe limitations in the third preceding paragraph above (which limitations, however, it of course still obeys). In this case with all angular deviations including maximum ones-just as with substantially less-than-maximum ones in the Figure 4 structure-the similarly directed oscillation peaks, although not substantially curtailed in amplitude relative to the amplitudes at the remaining portions of the fundamental cycle, will be somewhat widened and invested with substantially llat tops each representing the time of transit of the reed while juxtaposed to both vertical edges of the surface 55 (or 45').

Figure 6 illustrates a further modified pick-up electrode 65 having a reed-ward face 65' of circular configuration. Obviously this too obeys the limitations set forth above. It has the further advantage that at all angular deviations down to the smallest there is retained some pointing at the tops of the similarly directed oscillation peaksin other words, substantially at tops are avoided.

In describing my invention above I have done so on the tacit assumption that the angular deviation of the portion of the reed passing the pick-up stays constant during the time of transit of the reed while at all juxtaposed to the pick-up. Actually, of course, there will be some change of this deviation during the time of transit, since the lowest and principal frequency of the angular deviation is that of the second-partial vibration of the reedi.e., is many times the fundamental frequency of the reed (e.g., 6.28 times, for a uniform-cross-section unweighted reed). The lowest-frequency and principal effect of this change occurs at double the second-partial vibrational frequency, and consists of the introduction of a component of that double frequency into the translated oscillations at minute intervals (representing the transit times mentioned above) occurring twice in every fundamental cycle of substantial vibration of the reed. The ear senses this in the output tone as an inharmonic component, high in frequency, and Very highly damped (since the second-partial vibration is itself .relatively highly damped, and its double-frequency derivative here under discussion tends to decrease in amplitude approximately as the square of its amplitude). This component may be fairly substantial in the case of the structure of Figures 1 through 3, contributing to an initial roughness of the tone. It is very favorably reduced in the structures of Figures 4 and 5, and is substantially eliminated in the Figure 6 structure-especially when, as is preferred and illustrated, the pick-up is placed longitudinally of the reed at the second-partial node.

Such traces of this component as may remain even with the Figure 4 or 5 structures are not usually found objectionable, since they have been attenuated to the point Where they no more than simulate the initial ring heard on strong excitations in the lower and middle registers of the conventional piano (resulting from minute longitudinal string vibrations, wrapping-wire characteristics in the case of loaded strings, etc.).

It will be understood that while I have disclosed my invention with particular reference to capacitative pickups, no unexpressed limitation thereto is necessary or intended, since obviously it may equally well be applied to pick-ups of the magnetic or other types. And generally, while I have disclosed my invention in terms of specific embodiments thereof, it will be understood that unnecessary limitations are not thereby intended, since by the disclosure various modifications will be suggested to those skilled in the art. Such modifications will not necessarily constitute departures from the scope of the invention, which I undertake to express in the appended claims.

I claim:

l. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and Vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at at least a lower one of its upper-partial frequencies, of suicient magnitude so that the plane of the portion of the reed which passes the pick-up is subjected to oscillatory upper-partial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, initially at least of the order of one-eighth of a right angle, the reed-ward face of the pick-up when the reed is most fully juxtaposed thereto being at least substantially as fully exposed to the edge of the reed at the extremes of such oscillatory deviation as in the absence thereof.

2. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at at least a lower one of its upper-partial frequencies, of suicient magnitude so that the plane of the portion of the reed which passes the pick-up is subjected to oscillatory upper-partial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, initially at least of the order of one-eighth of a right angle, the longitudinal extent of the reed edge exposed to the pick-up when the reed is most fully juxtaposed thereto being at least substantially as great at the extremes of such oscillatory deviation as in the absence theerof.

3. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at at least a lower one of its upper-partial frequencies, of sufficient magnitude so that the plane of the portion of the reed which passes the pick-up is subjected to oscillatory upperpartial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, initially at least of the order of one-eighth of a right angle, the reed-ward face of the pick-up having in the direction of the length of the reed an effective extent not substantially greater than the product of its effecive extent in the direction of reed vibration by the cotangent of the maximum angle of said deviation.

4. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration at at least a lower one of its upper-partial frequencies, the reed-Ward face of the pick-up being substantially circular.

5. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed at approximately the node of the second-partial vibration of the reed and Vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at its second-partial frequency, of sutlicient magnitude so that the plane of the portion of the reed which passes :the vpick-up is subjected to oscillatory second-partialfrequency angular deviation, about the plane of said portion established by pure fundamental vibration, initially at least of the order of one-eighth of a right angle, the reed-ward face of the pick-up when the reed is most fully juxtaposed thereto being at least substantially as fully exposed to the edge of the reed at the extremes of such oscillatory deviation as in the absence thereof.

6. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the feed at approximately the node of the second-partial vibration of the reed and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at its second-partial frequency, of sufficient magnitude so that the plane of the portion of the reed which passes the pick-up is subjected to oscillatory secondpartial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, initially at least of the order of one-eighth of a right angle, the longitudinal extent of the reed edge exposed to the pick-up when the reed is most fully juxtaposed thereto being at least substantially as great at the extremes of such oscillatory deviation as in the absence thereof.

7. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed at approximately the node of the secondpartial vibration of the reed and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at its second-partial frequency, of sufficient magnitude so that the plane of the portion of the reed which passes the pick-up is subjected to oscillatory second-partial-frequency angular deviation, about the plane of that portion established by pure fundamental vibration, initially at least of the order of one-eighth of a right angle, the reed-ward face of the pick-up having in the direction of the length of the reed an effective extent not substantially greater than the product of its effective extent in the direction of reed vibration by the cotangent of the maximum angle of said deviation.

8. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed at approximately the node of the second-partial vibration of the reed and vibratorily passed by the reed, an impulse exciting means adjacent the reed for setting i-t Ainto decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration at its second-partial frequency, the reed-ward face of the pickup being stubstantially circular.

9. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at at least a lower one of its upperpartial frequencies, of sufficient magnitude so that the plane `of the portion of the reed which passes the pick-up is temporarily subjected to oscillatory upper-partial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, of the general order of one-fifth of a right angle, the reed-ward face of the pick-up when the reed is most fully juxtaposed thereto being at least substantially as fully exposed to the edge of the reed at the extremes of such oscillatory deviation as in the absence thereof.

10. In combination in an electrical musical instrument, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at at least a lower one of its upper-partial frequencies, of suflicient magnitude so that the plane of the portion of the reed which passes the pick-up is temporarily subjected to oscillatory upperpartial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, of the general order of one-fifth of a right angle, the longitudinal extent of the reed edge exposed to the pick-up when the reed is most fully juxtaposed thereto being at least substantially as great at the extremes of such oscillatory deviation as in the absence thereof.

11. In combination in an electrical musical instrumeut, a fixed-free reed, an electric translation pick-up alongside the reed intermediate the reed extremities and vibratorily passed by the reed, and an impulse exciting means adjacent the reed for setting it into decadent free vibration at its fundamental frequency and simultaneously into decadent free vibration, at at least a lower one of its upper-partial frequencies, of sufficient magnitude so that the plane of the portion of the reed which passes the pick-up is temporarily subjected to oscillatory upperpartial-frequency angular deviation, about the plane of said portion established by pure fundamental vibration, of the general order of one-fifth of a right angle, the reed-ward face of the Pick-up having in the direction of the length of the reed an effective extent not substantially greater than the product of its effective extent in the direction of reed vibration by the cotangent of the maxirnum angle of said deviation.

References Cited in the file of this patent UNITED STATES PATENTS 2,027,074 Miessner Ian. 7, 1936 2,413,062 Miessner Dec. 24, 1946 2,414,886 Miessner Jan. 28, 1947 2,581,963 Langloys Ian. 8, 1952

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