Title:
Apparatus for the production of music
United States Patent 2138500


Abstract:
This invention relates to musical instruments, and more particularly to those wherein electric oscillations are selectively .produced, controlled and translated into sound. One object of the invention is to provide an instrument of this type wherein, in the initial production of the oscillations,...



Inventors:
Miessner, Benjamin F.
Application Number:
US10797136A
Publication Date:
11/29/1938
Filing Date:
10/28/1936
Assignee:
MIESSNER INV S INC
Primary Class:
Other Classes:
84/283, 84/382, 84/383A, 84/729, 84/737, 984/366
International Classes:
G10H3/16
View Patent Images:



Description:

This invention relates to musical instruments, and more particularly to those wherein electric oscillations are selectively .produced, controlled and translated into sound.

One object of the invention is to provide an instrument of this type wherein, in the initial production of the oscillations, there is employed an element vibratable at will at any of a plurality of frequencies, as distinguished from the employment of a plurality of elements selectively vibratable.

An allied object of the invention is to provide such an instrument with appropriate controls over its tonal output.

Another object is to provide an instrument wherein there are employed without unfavorable results control systems, among others, of a type poorly adapted for the simultaneous control of oscillations not strictly harmonically related to each other.

Another object is the provision of a controllable air-column instrument operating electronically.

Another object is the provision of a mouth-reed Sinstrument operating electronically.

Still another object is the provision, in a mouth-reed instrument, of efficient translating means not interfering with the normal vibration of the reed.

Still another object is the provision of translating means readily adjustable in and removable from the mouthpiece of the instrument.

Still another object is the suppression of the actuation of the translating means by extraneous vibrations.

Yet another object is the suppression of acoustic feed-back to the reed of the instrument.

Yet another object is the suppression of acoustic feed-back to the air-column of the instrument.

It is another object to provide improved control means particularly useful in the instruments above discussed.

It is particularly an object to provide improved means for introducing formants into the oscillations.

It is another object to provide improved controls over the formant additions.

It is another object to provide means for relating the formant additions in novel manner to the primary oscillations.

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

In the description reference is had to the accompanying drawings, of which: Figure 1 is a view, with a portion in elevation but principally diagrammatic, of an electronic instrument according to my invention; Figure 2 is a much enlarged cross-sectional view of the mouthpiece with translating means, and immediately adjacent portions, of the instrument of Figure 1; Figure 2a is a view similar to Figure 2 but illustrating a modification thereof in respect of the translating means; Figure 3 is a plan view of the extremity of the mouthpiece of Figure 2 or 2a, with the reed and translating means removed; Figure 4 is a cross-sectional view of a modified combination of mouthpiece and translating means; Figure 5 is a plan view of the extremity of the mouthpiece of Figure 4, with the reed and translating means removed; Figure 5 is a cross-sectional view taken along the line 6-6 of Figure 4; Figure 7 is a view similar to Figure 4 but illustrating an additional feature of my invention; and Figure 8 is a view, partly sectional but principally diagrammatic, of a modified electronic instrument embodying my invention.

Particular mention may be made of the formant and anplitude distorting circuits. Formant circuits in electronic musical instruments have been heretofore employed; as is understood, they function to introduce into each successive fundamental cycle of the oscillations passed through them a train of damped oscillations, which train is reinitiated with each new fundamental cycle-the train in the previous cycle having either been substantially entirely damped out or being terminated by the initiation of the new train. The frequency or frequencies of these damped oscillations are normally higher than the fundamental frequency of the oscillations passed through the circuit, but have no necessary harmonic relationship to those fundamental oscillations; nevertheless, since their effect on the oscillations is a strictly recurring one with each fundamental oscillation cycle, the composite output oscillations from the formant circuit may still be resolved wholly into a series of harmonically related components and thus still remain a fit musical tone. Formant circuits operate electrically in the same manner as various peculiarities in the configuration of, and various resonance cavities in, the air columns of acoustic instruments. In my preferred electronic instrument I employ a mouth-reed or other air column instrument in which these peculiarities of configuration and resonance cavities, etc., are of course fixed; nevertheless, by the use of formant circuits, I am able to produce the effect of varying these characteristics at will. Therefore in this instrument I obtain a unique and special benefit from the employment of the formant circuits. It is also believed that the tendencies toward abrupt discontinuities In the tone and translated electrical output from the mouthreed, which are probably largely responsible for its characteristic pungency of tone, are particularly well suited for the efficient excitation of a formant circuit. And of course it is also to be noted that the usually restricted fundamental -pitch range of the mouth-reed or other air column instrument naturally conforms itself to the requirements of the formant circuit for effective operation-that the fundamental oscillation frequency be below the fixed formant frequency or frequencies and yet not too many octaves therebelow.

As to the amplitude distorting circuits, for example having a non-linear response-stimulus characteristic, these have been elsewhere proposed with instruments having a plurality of mechanical vibrators; but to their use the objection has attached that upon simultaneous vibration of a plurality of the vibrators (at least other than vibrators exactly integrally related to each other in frequency) extremely unpleasant beat frequencies have been produced. This objection has not been by any means circumvented by any prescription of careful use of the multivibrator instrument to avoid simultaneous vibration of a plurality of vibrators, since unavoidable occasional failures of due care, and the frequent tendencies to glissando playing with slight overlapping of vibrations of different vibrators, bring in the unpleasant effects to an ample extent to render the system musically worthless. But the single reed of the mouth-reed instrument, or a single vibrator aptly associated with the aircolumn instrument broadly, is incapable of significant simultaneous vibration at inharmonically related frequencies; the closest possible approaches to overlapping tones may be achieved with an automatic safeguard against actually overstepping the boundary. This renders these instruments uniquely adapted for use with the distorting circuit. And by the use of these distorting circuits a single instrument may be extended in its pitch range, and special tonal effects of simultaneous playing of a tone and its octave for example, may readily be achieved.

From a quite general view-point the electronic instrument of the type described, but provided only with transmission-frequency (or tone) control, comprises an air column whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, a mechanical vibrator responsive with the air column, an electric circuit responsive to the vibrator, and means in the circuit for modifying Sits response to the vibrator. On the other hand the electronic instrument with either the formant and/or frequency distorting means comprises the air column, mechanical vibrator and electric circult each responsive as above, and also means in the circuit for introducing into the response of the circuit characteristics of other and different air columns.

Proceeding now to a more detailed description of my electronic instrument, reference is invited to Figure 1. The mouth-reed instrument appears as I; this may for example be any form of known acoustic instrument of this type, but has been illustrated by way of example as a clarinet. It is provided with a suitable form of pick-up, or mechanico-electric translating device, typical ones being illustrated detalledly in later figures and being hereinbelow detailed described. In Figure 1 the output leads from the pick-up are designated as 2, and will be seen leading to the amplifier 3. The amplifier may be provided with the volume control schematically indicated as 4, and with a tone control Indicated as 5; the tone control may be of any known variety-such, purely by way of example, as has been illustrated in the circuit 18-IS of Figure 2 of U. S. Patent No. 1,929,032 to myself and Charles T. Jacobs, issued October 3, 1933.

To the output of the amplifier 3 have been shown connected a plurality of formant circuits and controls therefor, this portion of the system lying between the lines A-A and B-B. By way of example I have illustrated schematically two such circuits, but it will be understood that no limitation to this particular number is intended. Means are provided for selectively varying the amplitude of oscillations fed to each of the circuits; typically these means may be a potentiometer 6 equipped with the variable contacts 6a and 6b, each operable over the entire potentiometer without interference by the other. The output of the amplifier 3 is immediately connected across the potentiometer; and each of the formant circuits 7a and 7b is connected between one end of the potentiometer and a respective one of 23 the contacts 6a and 6b. The formant circuits themselves may be of any known variety; for example they may be of any one of the forms shown and described in U. S. Patent No. 1,933,299 to Oscar Vierling, issued October 31, 1933, or a form shown and described in U. S. Patent No. 2,039,201 to Trautwein. As employed in the instant invention, each circuit is equipped with all controls appropriate to it; for example, assuming the circuit to be of the form shown as 137' in Figure 4 of the mentioned patent to Vierling, the controls may be the variable condenser 286 and variable resistor 284 of that figure. The controls have been indicated schematically as 8. The output of the several formant circuits may De combined, for example by paralleling of their output terminals.

The combined output of the formant circuits may be led into the amplitude-distorting portion of the complete instrument, which is illustrated between the lines B-B and C-C of Figure 1.

I do not intend the showing of this portion to be limitative, as obviously various known forms of amplitude-distorting and frequency-changing circuits may be employed--such for example as that shown in Figure 3 of U. S. Patent No. 1,886,687 to Charles T. Jacobs, issued November 8, 1932.

This particularly illustrated system, however, comprises a transformer 9 having the primary 9a to which the formanat circuit output is connected, and the secondaries 9b and 9c. Across the secondary 9b are connected in series two rectifiers 10 each arranged to pass current only in the direction of (or only away from) their junction.

Output leads I |b are provided for this portion of the system, one connected to the junction of the two rectifiers and the other connected to the movable contact 12a of a potentiometer 12 shunting the secondary 9b. For the secondary 9c there are provided output leads I c. The two sets of -output leads are connected to a potentiometer 13, from which the oscillations are transmitted to further portions of the system hereinafter described. The function of the potentiometer 13 is to mix the oscillations from the two sets of output leads I Ib and I Ic in variable proportions; and as a typical arrangement for performing this function I have shown the output leads I Ib connected from one end of the potentiometer to its movable contact 13a, and the output leads IIc connected between the other end of the potentiometer and the movable contact, with the leads to further instrument portion connected across the entire potentiometer. In order to avoid shortcircuiting the secondary 9c by a downward adjustment of the movable contact 13a, a resistance 14c may be inserted in one of the output leads SIc; and an analagous resistance IIb may be inserted in one of the output leads I Ib.

Contact 12a of potentiometer 12 being adjusted to the center of that potentiometer, and assuming the rectifiers to be of mutually similar characteristics, no oscillations of the fundamental' frequencies applied to the primary 9a will appear across the leads I Ib; but there will appear across these leads even multiples of those frequencies, particularly a multiple of 2 times. Under these conditions the leads I b become a source of oscillations of double frequency, while the leads I e of course remain a source of oscillations of single frequency. By the movable contact 13a there may be controlled the relative percentages of these two series of oscillations which are passed on to the further portions of the system and to the loudspeaker. If the two rectifiers be somewhat unbalanced in their characteristics, this condition may be offset by an appropriate offcenter adjustment of the movable contact 12a, to maintain the operation just outlined. If desired, however, the movable contact 12a may be otherwise displaced from the center of the potentiometer 12, so that the leads Ilb become a source of oscillations of variously compounded waveforms-all of course distorted or altered from the waveform of the oscillations applied to the primary 9a. In turn these variously constituted waveform oscillations may be combined in varying relationships with the first power oscillations from the leads i c, by the movable contact 13a. It is to be noted that with the first mentioned manner of operation an adjustment of the contact 13a to its bottommost position will effectively shift the frequency range of the instrument upwardly by precisely one octave.

From the implitude-distorting, or frequencymodifying, portion of the instrument the oscillations may pass to the tremolo-introducing system, which has been illustrated between the lines C--C and D-D. This has been illustrated as comprising a pentode tube 15, preferably of the variable-mu variety, with means for modulating its bias at a low frequency. Thus the leads from earlier circuit portions may be connected one to the control grid of the tube and the other through a resistance 16 and normal biasing battery or other voltage source 17 to the cathode of the tube. Across the resistance 16 may be connected a low frequency oscillator 18, having the frequency and amplitude controls 19 and 20. By the voltage drop from the oscillator output occuring across the resistance 16, the bias of the tube 15, and hence the amplification factor of the tube, are modulated to produce the tremolo. The frequency of the tremolo will of course be adjusted 05 by an adjustment of the frequency of the oscillator 18, and the depth or amplitude of the tremolo by an adjustment of the amplitude of the oscillator output-by the controls I9 and 20 respectively.

From the output of the tremolo-introducing system the oscillations may pass to a further am- 1 plifler 21, also if desired equipped with volume and tone controls 22 and 23, and therefrom to the loudspeaker 24 for translation into sound.

T7 In Figure 2 I have illustrated in much enlarged, cross-sectional form the mouthpiece end of the instrument I of Figure 1. (Arbitrarily the surface of the mouthpiece against which the reed is clamped has been illustrated and described as the "top"; but of course no limitation, either in structure or playing position, is thereby intended.) Figure 3 is a simple top view of the mouthpiece of Figure 2. There is shown as 31 the end of the instrument body proper, this being provided with a reduced diameter extension 31 a adapted to fit into the connecting portion 32, the mouthpiece 33 is provided with the reduced, diameter extension 33a which is adapted to fit into the connecting portion 32 from the opposite direction, these three portions having been shown drawn apart in Figure 2. The mouthpiece 33 is a generally cylindrical body having the internal air passage 34; its bottom is extended, however, to form a sloping flange 35, and the sides are extended to form with the top of the mouthpiece an aperture 36 communicating with the air passage 34. The top edges 36a of the sides and of the flange extremity and a portion 36b of the top of the mouthpiece, all bounding the aperture 36, are finished to an integral plane, or almost-plane, surface. The reed 37 is secured over the aperture 36 and surface 36a, the base 37a of the reed being clamped to the surface 36b by the strap 38, and the reed extending across the aperture in increasing slight spacing from the surface 36a to terminate in the free end 37b just above the extremity of the flange 35. There is accordingly left around the outer portion of the reed a thin air-inlet 39 communicating with the passageway 34 through a space 39a bounded by the flange 35, the sides converging therewith, and the reed itself; the thickness of the air-inlet 39 is of course varied or modulated by the vibration of the reed, which in turn is produced by the apt passage of air through the inlet. In this paragraph it is intended to describe conventional structure.

In picking up or translating into electric oscillations the vibrations of the reed, I have found it important so to introduce the pick-up or translating device into the mouthpiece that there will be preserved substantially unobstructed the normal air flow from the inlet 39 through the space 39a-in other words, a substantially free air passage therethrough. This air flow tends to be principally central of the space 39a or in general strongest along a central line such as M-N joining the inlet 39 with the center N of the end 34a of the normal fixed diameter portion of passageway 34, which end may be considered the effective mouthpiece outlet. I have preferred to meet the specification of substantial non-obstruction by employing a relatively thin translating device, and disposing it closely along one wall of the space 39a-for example at least substantially wholly to one side of (e. g,, above or below) the central line M-N. One arrangement, illustrated in Figure 2, is of the translating device closely adjacent the inner surface of the flange 35, and below the line M-N. Thus in this figure will be seen the thin iron pole-piece 40, for example .02 inch thick and .2 inch wide, surrounded by a coil 41 of many turns of fine insulated wire. This coil and pole-piece may be held in place in any convenient manner, such as by wax applied in heated condition and allowed to cool. It is necessary for the completion of a device of this type to provide some means of magnetizing the pole-piece; in Figure 2 I have shown such means in the form of a permanent magnet 42, which may be secured in a suitable groove 43 formed therefor in the bottom of the main portion of the mouthpiece 33, the inner end of the pole-piece 40 being suitably bent to lie in contact with the outer end of the magnet 42. For co;5 operating with this translating device it is necessary to provide on the reed, which is normally of non-magnetic material, a small armature 44; this is desirably of extremely small thickness and of restricted area, in order that its attachment to the reed-in this figure very close to the reed extremity 37b, immediately over the outer end of the pole-piece 40-shall negligibly affect the vibrational characteristics of the reed. From the coil 41 a pair of leads 45 are extended to suitable m5 terminals, such as the terminals 46 inset into and passing through the bottom portion of the mouthpiece, to which the leads 2 hereinabove mentioned may be removably secured, as by the connectors 47.

In Figure 2a I have illustrated an almost identical structure, differing only in that the permanent magnet 42 and groove 43 therefor are omitted, and that in series with one of the leads 2 is provided a battery or other current source 42b. This simply illustrates an alternative way of magnetizing the pole-piece 40 which has, however, a slight advantage in respect of the weight of the mouthpiece.

In Figures 4, 5 and 6 I show an alternative embodiment of my invention in respect of arrangement of the translating device in the mouthpiece, which itself may be essentially as before; in this embodiment the translating device lies substantially wholly above the line M-N. The surface 36b is now provided with a central groove 48, of cross-sectional dimension just accommodating a permanent magnet 42'; in a short longitudinal section 48a adjacent the aperture 36 this groove is conveniently cut through into communication with the passageway 34. The magnet 42' rests in this groove, preferably extending to about the normal inward boundary of the aperture 36; the base 37a of the reed rests against the two portions of the surface 36b straddling the magnet, and the clamping of the reed base may serve to hold not only the reed but also the magnet in place.

The magnet forms a base to which the other portions of the translating device may be secured. Thus to the bottom of the magnet in the cutthrough groove portion 48a may be glued or cemented the innermost portion of the top of the pole-piece 40'-of thin material as in the case of the pole-piece 40 of Figure 2. The polepiece extends outwardly beyond the extremity of the magnet 42', and is surrounded by a relatively fiat coil 41', preferably of many turns of fine wire.

In turn beyond the coil 41' the pole-piece 40' is curved upwardly as at 40a' to terminate in slight spaced relationship to a thin, small armature 44' secured to the bottom of the reed intermediate its free extremity 37b and base 37a. Most thoroughly to secure the pole-piece 40' to the magnet 642', as well as to secure the coil 41' on the polepiece, a coating 49 of cement (such as a celluloseanyl-acetate cement) may be flowed over the coil, into contact with the pole-piece 40' at the coil extremities, into contact with the extremity of magnet 42', and over the inner bottom extremity of the pole-piece into contact with the bottom of the magnet. Leads 45 may connect the coil 41' with terminals (not shown) such as 46 of Figure 2.

One especial advantage of the structure illustrated in Figures 4, 5 and 6 is the ready adjustability and removability of the translating device upon loosening of the clamp 38.

Figure 2 illustrates another feature which I have found desirable in an instrument of this character. This consists in vibrationally insulative means disposed between the mouthpiece 33 and the connector 32, and between connector 32 and the main body of the instrument 31. This insulation appears as the soft rubber or other compliant cylinders 51a and 53a secured around the extending portions 3 Ia and 33a of instrument body and mouthpiece respectively, and adapted to fit within the connecting portion 32; together with the soft rubber or other compliant annular pieces i5b and 53b secured against the shoulders 31b and 33b formed between 31a and 31 on the one hand, and between 33a and 33 on the other.

When the portions 31a and 33a are inserted into the connecting portion 32 so that the insulating pieces 51b and 53b are in contact with the connecting portion 32, the extremities of the portions 31a and 33a will lie approximately on the lines shown within the connecting portion as X and Y, and will hence be spaced from one another. It is known to employ cork or like cylinders about the portions 31a and 33a, but these are normally precluded from functioning as even inefficient vibration insulation by virtue of the usual direct contact between the shoulders 31b, 33b, and the connecting portion 32. One advantage of the vibration insulationhaving to do with acoustic feed-back-is hereinafter mentioned. A particular advantage of this insulation, however, lies in the suppression of influence on the reed and translating device-and hence of unwanted translation-of spurious vibrations of the main body of the instrument I by the manipulations themselves of the mechanical valve system comprising the playing keys Ib; this influence, if uncounteracted, may in certain cases give rise to thumping and other unpleasant noises in the sound output of the complete electronic instrument.

It is well understood that in electronic instruments wherein the vibrations of mechanical vibrators are amplified and translated into sound, some danger exists of sustained oscillation of the system at some frequency or frequencies by virtue of acoustic feed-back from the loudspeaker or equivalent to the vibrators. In a mouth-reed electronic instrument such as I have described the danger of acoustic feed-back to the vibrator is in general relatively small, in view of the small area of the vibrator (reed) and resulting small coupling to the air. Particularly during playing, when the vibratile portion of the reed is substantialy shielded by the player's mouth, is this danger almost non-existent. But during rest intervals when the player has the mouthpiece removed from his mouth, in cases where high amplification and nearby loudspeaker are employed, trouble may sometimes be encountered. In Figure 7 I have shown an automatic arrangement for obviating this trouble.

This consists in a switch 60 connected with the translating device and biased to normally reduce (for example to zero) the sensitivity of the latter, but responsive to the lips of the player to restore such sensitivity to normal. For example the switch may comprise a small contact member 60c secured inside the flange 35; a flat spring 60a secured on the outside of the flange 35 and lightly outwardly biased; and a hook member 60b secured to the spring 60a, passing through the flange, and cuiving about to be held normally (by the bias of spring 60a) in contact with the member 60c-the member 60c and spring 60a being connected as by leads 60d across the leads 45. Thus normally the switch 60 is closed and shorts out the translating device; but when the player has the mouthpiece in his mouth the pressure of his lip on the spring 60a overcomes its light bias, opening the switch 60 and assuring normal action of the translating device, , In the figures thus far described the single mechanical vibrator responsive only conformably with the variable frequency air column, and in turn exciting the electric circuit, has been the reed 37 of the instrument I. It is possible in accordance with my invention, however, to employ alternatively or additionally a mechanical vibrator similarly responsive but not forming a part of the basic instrument as conventionally known. This vibrator inay be for example the diaphragm of a microphone which, by virtue of positioning and/or other means hereinafter described, is made responsive substantially solely to the vibrations of the air column. Such an arrangement I have illustrated in Figure 8, wherein appears the instrument I' (similar for example to instrument I of Figure 1), with the microphone 62 (having diaphragm 61) disposed closely in front of the bell or air outlet )a' of the'instrument so as to be responsive in the prescribed manner.

In this figure I have shown the vibrator or diaphragm 61 employable, if desired, additionally to the vibrator or reed 37, in controllable amplitude and phase relationship thereto. Thus the output leads 63 from the microphone 62 may be connected across the potentiometer 64; the output leads 2 from the translating device associated with the reed 37 (as in earlier figures) may be connected across the potentiometer 65; fixed center-taps 64a and 65a on the two respective potentiometers may be connected together; and to variable contacts 64b and 65b on the two respective potentiometers may be connected leads 2' leading to amplifier 3 and succeeding circuit portions as shown in Figure 1. It will be understood that by adjustment of the variable contacts 64b and 65b there may be passed to the amplifier 3 and succeeding circuit portions any desired fraction (up to half) of the outputs of the leads 2 on the one hand and of the leads 63 on the other, in either of two phases. Since the harmonic distributions in the vibrations of the reed 37 and of the diaphragm 61 are almost of necessity significantly different, a very material tone quality control may be achieved by adjustment of these variable contacts.

It will of course be understood that in the electronic instrument of Figure 8 the translating device, leads 2 and potentiometer 65 may be 00 omitted (corresponding to a setting of the variable contact 65b at the center-tap 65a), so that the diaphragm 61 becomes the sole mechanical vibrator. And it will further be appreciated that under these conditions the instrument I' may 05 assume the form of any air-column instrumenta brass instrument for example-no longer being necessarily limited to a mouth-reed instrument.

Acoustic feed-back to the reed when employed has been considered above. In the electronic instrument of Figure 8, however, there may take place under some circumstances acoustic feedback to the diaphragm 61. And with any of the instruments herein referred to other acoustic feed-backs may sometimes be troublesome. For Mi example, acqustic feed-back may occur to the main body of the instrument-though in the particular case of a mouth-reed instrument employing the vibration insulation illustrated in Figure 2 this feed-back is normally inconsequential.

Again, however, acoustic feed-back may occur to the air column itself of the instrument, both through the bell la' and through the usual apertures opened by the valves or playing keys of the instrument. To obviate any possibility of sustained oscillation from any of these feedbacks I have shown the main portion of the instrument I' of Figure 8 surrounded by acoustic shielding 66.

This may comprise for example a metal or other rigid casing 66a fully surrounding the main portion of the instrument (including the bell la' and playing keys Ib') and the microphone 62 when employed; and a lining 66b of felt or other sound-absorbing material within the casing 66a.

In the casing, particularly at and near the extremity associated with the bell la', may be provided a plurality of holes 66c; these permit air egress from the enclosure. The lining 66b, covering these holes, by virtue of its porosity does not preclude this egress, but does prevent substantial sound passage in either direction through the holes. The structure therefore not only prevents feed-back to within the enclosure, but also vastly reduces the normal acoustic output so that the electrically produced output is 3C not impaired in respect of the various distinctive characteristics imparted to it by the controls.

To preserve the playability of the instrument, the playing keys Ib' may be effectively extended to without the enclosure in any suitable manner.

Thus in Figure 8 I have illustrated a plurality of plungers 67 passing freely through the casing 66a and lining 66b, having the exterior playing buttons or keys 67a, and having the interior buttons or bushings 67b respectively biased into light contact with the several playing keys Ib' of the instrument I' by the respective expansion springs 67c surrounding the plungers.

In the instrument of Figure 8 I have not shown in detail the tremolo-introducing system lying between lines C-C and D-D, but instead have indicated this schematically as 28, with appropriate controls 29 and 30 which may for example correspond with the controls 19 and 20 of oscillator 18 of Figure 1. On the other hand, instead of showing purely schematically both the formant circuits 7a and 7b of Figure 1, I have shown one of them--b'-fully developed in a form particularly appropriate for at least one of the formant introducing means in an instrument of the type herein described.

This formant circuit is one wherein the formant additions are produced by the beating together of two series of high frequency oscillations. The formant additions are controlled in amplitude by the instantaneous amplitude of the translated oscillations (e. g., those from amplifier 3), and preferably this control is effected by utilizing those oscillations to control one of the series of high frequency oscillations before their beating together. The formant additions are effected, in accordance with the instantaneous translated oscillation amplitude, either to one-half, or equally to both halves, or unequally to both halves, of each cycle of the translated oscillations, as desired. The basic frequency of the formant additions may be readily controlled at will simply by variation of the frequency of one of the series of high frequency oscillations before beating to- 7y gether. Both series of high frequency oscillations may be rich in their own harmonics, and a series of filters or other means may be employed to control the harmonic distribution of one of the series; then upon the beating together there will be available for formant additions not only oscillations of that frequency which is the difference of fundamental frequencies of the two series, but also, in controlled mutual relationships, oscillations of integral multiples of that difference frequency. Optionally, and with the employment (as distinguished from the omission) of certain of the illustrated components, the translated oscillations may be made to have an influence on the frequency as well as on the amplitude of the formant additions-e. g., the formant additions mvy be made either to rise in frequency, or to lower in frequency, or to divide between raised and lowered frequency additions, as the frequencies of the translated oscillations (e. g., from amplifier 3) changes-these changes not, however, disturbing the arbitrary nature of the relationship of formant addition frequency to translated oscillation frequency.

Reference now being had to the formant circult or system 7b' of Figure 8, there will be seen the two high frequency oscillators 1I and 72; it is convenient to consider their fundamental frequencies as Fi and F2 respectively. To the output of oscillator 71 are connected the leads 73 leading for example to the input system of tube 74 (modulator q5 and filter 76 being optionally inserted in tandem in the leads 73 for purposes hereinafter discussed); tube 74 and its associated circuit represents a non-limitative example of means for controlling the amplitude of the formant additions-and more specifically of the output of oscillator 71-in accordance with instantaneous translated oscillation amplitude. Thus the leads 73 may be connected, one to the control grid of tube 74, and the other to the cathode of the tube through the resistance 77 and biasing battery or other potential source 78, the tube 14 being biased just or approximately to cutSoff in the basence of voltage across resistance 77.

To this resistance, however, is connected the secondary 79b of a transformer 79, of which the primary 79a is connected across leads 80 which convey the translated oscillations from input to output of the formant circuit. Were the connection of secondary 79b to the resistance 77 a simple connection, the voltage appearing across the resistance 77 from the transformer would be alternating; the algebraic addition to the negative bias of tube 74 would be alternately positive and negative, and the tube would pass high frequency oscillations from oscillator 11 only during half of each translated oscillation cycle in accordance with the instantaneous amplitudes during that half cycle. This, as will be apparent, would result in formant additions during those half cycles only. In order that this condition shall not obtain except when desired, I have shown both ends of secondary 79b connected to one end of resistance 77 through respective rectifiers 81a and 81b similarly poled; a potentiometer 82 connected across the secondary; and the movable contact 82a of the potentiometer connected to the other end of the resistance 77, preferably through a resistance 83. When the contact 82a is positioned centrally of the potentiometer, both half cycles of the translated oscillations will cause similarly proportioned and similarly directed voltage pulses across the resistance 77, the two rectifiers functioning alternately; by properly poling the rectifiers these voltage pulses may be rendered of a direction to decrease the negative bias of tube 74, and this tube of course passes high frequency oscillations from oscillator 71 during each pulse, or in both halves of each translated osclllation cycle. But as contact 82a is moved toward either extremity of the potentiometer, the pulse during one half cycle is increased and that during the other half cycle reduced (in the limit to zero); thus the formant additions may be caused to occur uniformly in both half cycles, or predominantly or wholly in either half cycle-the available choice between the two half cycles being a significant one in formant introduction.

The output circuit of tube 74 Is connected to the modulatoi schematically shown as 84, to which is also connected the output circuit of the oscillator 72. In this output circuit are connected a plurality of adjustable filter systems 85, preferably tuned to the fundamental and several harmonic frequencies of oscillator 72, by which the several partial components of the output of oscillator 72 may be controlled. Purely by way of example each system 85 may comprise a simple shunt circuit of series inductance 85a, capacity 85b, and variable resistance 85c.

Considering the frequencies of the oscillations applied to modulator 84, these will be seen to be Fi, 2Fi, 3Fi, etc., from oscillator 71, and F2, 2F2, 3F2, etc., from oscillator 72. The lower frequency components of the output of the modulator will accordingly be (Fi-F2), 2(Fi-F2), 3(F--F2), etc., or (F2-Fi), 2(F2-Fi), 3(F2-Fi), etc., according to whether Fi or F2 be greater. The instantaneous amplitudes of all of these will follow that of the F1, 2Fi, 3Fi series as established by tube 74; the relative amplitudes will depend among other things on the relative amplitudes of the components of frequencies F2, 2F2, 3F2, etc., as established by the adjustments of the several filter systems.

The output of modulator 84 may be connected to a low-pass filter 86 to remove components higher than the difference frequencies just discussed; and across the output of the filter 86 may 46 be connected a potentiometer 87, provided with the variable contact 87a. Accordingly a variable section 87b of the potentiometer, between one end and the variable contact 87a, becomes a source regulable in respect of amplitude, of formant additions already qualitatively regulated in various manners as above described. The formant additions from the section 87b may be combined with the simple translated oscillations in any convenient manner, as by serial insertion of this section 87b in one of the leads 80.

To prevent feed-back from the potentiometer section 87b and the transformer 79a, should this tend in any particular case to occur, there may be inserted between those components in the leads 80 any suitable "one-way" device, such as a stage of amplification 88. The output of the formant system lb', comprising the leads 80 to the right of potentiometer section 87b, may be combined in any convenient manner-as in Figure 1 for example-with the output of formant system 7a, and led to succeeding circuit portions as in that figure.

I have mentioned above that optionally in accordance with my invention the translated oscillations, for example by their frequency, may be made to have an influence on the frequency of the formant additions-an action with which some unique and pleasing effects may be obtained. This I accomplish for example by beating together oscillations from the high frequency oscillator I7 and translated oscillations, and preferably also by selecting for transmission certain bands of the beaten-together oscillations. In carrying out this procedure I insert, in the leads 73 from oscillator i7 to tube 74, the modulator 75 and filter 76, also applying the translated oscillations to the modulator as by leads 89 connected thereto from leads 80.

Letting Fa represent the fundamental frequency of the translated oscillations and Fb any or all harmonic frequencies thereof, the output of modulator 75 will contain components, among others, of frequency Fa, Fb, 2Fa, 2Fb, (Fj--Fb), (Fi-Fa), Fi, (Fi+Fa), (Fi+Fb), and 2F1. The filter 76 may be provided with low- and high-frequency cutoff controls 76a and 76b, respectively; and by their use the transmission of the above frequencies may be limited for example to (Fi-Fb) and (F--Fa), or to (Fi+Fa) and (Fi+Fb). Upon beating with F2 in modulator 84, the first of these above groups would provide formant additions of frequencies (Fi-F2-Fa) and (Fi-F-Fb), assuming Fi greater than F2; and the second of the above groups would provide formant additions of frequencies (F2-Fi-Fa) and (F2FI-Fb), assuming F2 greater than Fi-in either case the formant additions being reduced in frequency as the frequencies of the translated oscillations rose. Conversely the second above group would provide formant additions of frequencies (Fi-F2+Fa) and (F'--Fa+Fb), assuming Fi greater than F2; and the first above group would provide formant additions of (F2-Fi+Fa) and (F2-Fi+Fb), assuming F2 greater than Fiin either of which cases the formant additions would be increased in frequency as the frequencies of the translated oscillations increased.

The limitations mentioned in the foregoing paragraph are of course not the only ones which can be effected by the filter 76; its cut-off controls may be adjusted to pass the frequency Pi along with either of the mentioned groups, to include the fixed formant additions of the difference of Fi and F2 as before; or to pass Fi along with both the mentioned groups, to result in formant additions of frequencies both lowering and rising with translated oscillation frequency increase. Also, particularly readily with adjustments which pass (Fi+Fa) and (Fi+Fb),, the filter 76 may be made to pass also 2F1, 3Fi, etc. for the production of the additional fixed formants 2(Fi-F2), 3(Fi-F2), etc., or 2(F2-Fi), 3(F2-FD), etc., as above explained. (It is of course to be understood that by Fb in a broad sense is meant to be denoted the frequencies of more than one harmonic of the translated oscillations-for example Fm, Fn, Fp, etc.--so that mathematically each expression above involving Fb may be replaced by several in which Fb is replaced respectively by Fm, Fn, Fp, etc.).

It is of course to be understood that the various individual features of the illustrated formant system 7b' are not intended to be limitative, as for producing many of the actions which I have described alternative means will be recognized as available.

And as to each aspect of my invention, I do not intend that it shall be limited by the details of the embodiments illustrated and specifically described; for a particular example, there is intended no limitation of broader aspects to a magnetic translating device. Rather I intend in the following claims to claim my invention broadly, limited only by the state of the art.

I claim: 1. In combination in a musical instrument: a single air column vibratable selectively at a plurality of pitches but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, a mechanical vibrator arranged for vibration only conformably with said air column, an electric circuit responsive to said vibrator, and nonlinear means included in said circuit for altering qualitatively the response thereof to said vibrator.

2. In combination in a musical instrument: a single air column vibratable selectively at a plurality of pitches but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, a mechanical vibrator arranged for vibration only conformably with said air column, an electric circuit responsive to said vibrator, and means included in said circuit for introducing into the response of said circuit characteristics of other and different air columns.

3. In combination in a musical instrument: a single air column vibratable selectively at a plurality of pitches but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, a mechanical vibrator arranged for vibration only conformably with said air column, an electric circuit responsive to said vibrator, and formant introducing means included in said circuit.

4. In combination in a musical instrument: a single air column vibratable selectively at a plurality of pitches but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, a mechanical vibrator arranged for vibration only conformably with said air column, an electric circuit responsive to said vibrator, and amplitude distorting means included in said circuit. 5. In combination in a musical instrument: a single air column vibratable selectively at a plurality of pitches but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, a mechanical vibrator arranged for vibration only conformably with said air column, an electric circuit responsive to said vibrator, and frequency changing means included in said circuit.

6. In combination in a musical instrument: a single reed vibratable selectively at a plurality of frequencies but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, an electric circuit having its input excited only conformably with the vibration of said reed whereby to limit its input excitation at any instant substantially wholly to a plurality of harmonically related frequencies, and non-linear transmissionfrequency control means included in said circuit. 7. In combination in a musical instrument: a single reed vibratable selectively at a plurality of frequencies but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, an electric circuit having its input excited only conformably with the vibration of said reed whereby to. limit its input excitation at any instant substantially wholly to a plurality of harmonically related frequencies, and formant introducing means ineluded in said circuit.

8. In combination in a musical instrument: a single reed vibratable selectively at a plurality of frequencies but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, an electric circuit having its input excited only conformably with the vibration of said reed whereby to limit its input excitation at any instant substantially wholly to a plurality of harmonically related frequencies, and amplitude distorting means included in said circuit.

9. In combination in a musical instrument: a single reed vibraiable selectively at a plurality of frequencies but whose vibration at any instant may be resolved substantially wholly into a series of harmonically related components, an electric circuit having its input excited only conformably with the vibration of said reed whereby to limit its input excitation at any instant substantially wholly to a plurality of harmonically related frequencies, and frequency changing means included in said circuit.

10. In combination in a musical instrument: a mouthpiece having an air outlet, a reed secured on said mouthpiece and forming therewith an air inlet adapted for modulation concurrent with vibration of said reed, and a mechanico-electric translating device within said mouthpiece and responsive to said reed vibration.

11. The combination as claimed in claim 10, wherein said translating device is so disposed in said mouthpiece as to provide substantially free passage of air from said inlet to said outlet. 12. The combination as claimed in claim 10, wherein said translating device is disposed substantially wholly on one side of a central line from said inlet to said outlet.

13. In a mouth-reed instrument including amouthpiece and a reed secured thereto: a small armature carried by said reed, and mechanicoelectric translating means, responsive to said armature and secured to said mouthpiece.

14. In a mouth-reed instrument including a 10 mouthpiece, a reed and a clamp securing said reed against a surface of said mouthpiece: a mechanico-electric translating device responsive to said reed, said mouthpiece surface being provided with a groove and said translating device 43 having a portion disposed within said groove to be secured therein by said clamp.

15. In a musical instrument including a mouthpiece portion and a main portion comprising an air column and playing keys: mechanico-electric translating apparatus associated with said mouthpiece portion, and vibration insulation interposed between said two respective portions.

16. In combination with an instrument having a mouthpiece portion and a main portion comr5 prising a vibra*able air column and playing keys connected with said air column to vary the pitch of its vibration: mechanico-electro-acoustfc translating means for producing sound in accordance with the vibrations of said air column, 0o and acoustic rhielding disposed about said main instrument portion, said playing keys and said mouthpiece portion extending to without said shielding.

17. In a musical instrument having a mouthpiece and a reed secured to said mouthpiece: mechanico-electric translating means associated with said reed, means normally suppressing the sensitivity of said translating means, and means responsive to lip pressure on the mouthpiece for restoring said sensitivity.

18. In a musical instrument including a source of oscillations of musically related frequencies: means responsive to said oscillations for producing oscillations of multiples of their frequencies, transmitting means responsive to all said oscillations, and a single adjustable means for simultaneously varying the response of said transmitting means to said first and second mentioned oscillations in respectively opposite senses.

19. In a musical instrument including a source of oscillations of musically related frequencies: two sources of oscillations of different high frequencies, means for producing beats between said high frequency oscillations, and formant introducing means for said first mentioned oscillations comprising means for combining therewith said beats.

20. In a musical instrument including a source of oscillations of musically related frequencies: two sources of oscillations. of different high frequencies, at least one of said sources being controllable to vary the frequency of Its oscillations, means for producing beats between said high frequency oscillations, and formant introducing means for said first mentioned oscillations comprising means for combining therewith said beats.

21. In a musical instrument including a source of oscillations of musically related frequencies: two sources of oscillations of different high frequencies, means for producing beats between said high frequency oscillations, means for controlling the amplitude of said beats in accordance with instantaneous amplitudes of said first mentioned oscillations, and means for combining said controlled beats with said first mentioned oscillations.

22. In a musical instrument including a source of oscillations of musically related frequencies: means for introducing formant oscillations into said first mentioned oscillations, and means associated with said formant-introducing means for controlling its action selectively with respect to different portions of each cycle of said first mentioned oscillations. 23. In a musical instrument including a source of oscillations of musically related frequencies: means for introducing, into said first mentioned oscillations, formant oscillations comprising a plurality of harmonically related components; and means associated with said formant-introducing means for selectively regulating the relative amplitudes of said formant oscillation components.

24. In a musical instrument including a source of oscillations of musically related frequencies: means for introducing formant oscillations into said first mentioned oscillations, and means responsive to said first mentioned oscillations for varying the frequency of said formant oscillations. 25. The combination claimed in claim 16, wherein said translating means includes a microphone disposed within said shielding.

26. In a musical instrument having a mouthpiece and a reed secured to said mouthpiece: mechanico-electric translating means associated with and responsive to said reed, and means responsive to lip pressure on the mouthpiece for varying the sensitivity of said translating means.

27. In combination in a musical instrument: a mouthpiece having an air outlet, a reed secured on said mouthpiece and forming therewith an air inlet adapted for modulation concurrent with the vibration of said reed, and mechanico-electric translating means carried by said mouthpiece and responsive to said reed vibration.

BENJAMIN F. MIESSNER.