US3166622A

US3166622A - Breath controlled electronic musical instrument

Info

Publication number: US3166622A
Application number: US831654A
Authority: US
Inventors: Herbert M Neustadt
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-08-04
Filing date: 1959-08-04
Publication date: 1965-01-19
Anticipated expiration: 1982-01-19

Description

Jan. 19, 1965 H. M. NEUSTADT 3,166,622

BREATH CONTROLLED ELECTRONIC MUSICAL INSTRUMENT Filed Aug. 4, 1959 BY I H T TOPNE Y United States Patent 3,166,622 BREATH CONTROLLED ELECTRONIQ MUSICAL INSTRUMENT Herbert M. Neustadt, 257 Hanover St., Annapolis, Md. Filed Aug. 4, 195%, Ser. No. 831,654 22 Claims. (til. $4--1.il1)

My invention relates to a breath-controlled electronic musical instrument and more particularly to an electronic musical instrument in which not only volume and loudness but also pitch and quality are breath controlled.

In some electronic musical instruments of the prior art, the volume or loudness of sound is controlled by such hand or foot operated means as a potentiometer. This means can be operated at only a slow rate and it is accordingly very difficult to rapidly adjust this means in conjunction with the playing of a single note or chord to produce a desired attack or decay envelope. In other electronic musical instruments of the prior art, predetermined settings of attack and decay for the envelope of individual notes or chords may be set in by appropriate adjustments. However, these adjustments consume some time and it is not possible to rapidly reposition the settings to enable different attack and decay envelopes for individual notes closely following one another. Thus electronic musical instruments of the prior art cannot reproduce the subtle volume fluctuations which are normally produced by skilled musicians playing tradi tional instruments.

In other electronic musical instruments of the prior art provision is made for the adjustment of magnitude of harmonic overtones relative to the fundamental note in order to achieve variation in the quality of the sound produced. Again these adjustments take time; and it is not feasible to make a marked diiference between the quality of two notes played in rapid succession nor is it feasible to change rapidly the quality of a single note while it is being played. Electronic musical instruments of the prior art accordingly lack the subtle shades of interpretation which a musician would desire. Keyboard actuated electronic musical instruments of the prior art normally produce no tremolo or vibrato effect. However, controls are provided to introduce predetermined quantities of these effects. But being of a mechanical on-offor step-wise nature, the sound grates on the ears after some time because subtle variations are entirely absent.

One object of my invention is to provide an electronic musical instrument where the loudness, volume, or intensity of sound is breath controlled, enabling a musician to achieve an infinite variety of envelopes of attack and decay not only for long-sustained notes but also for notes played in rapid succession and enabling a musician to achieve a variety of amplitude modulation tremolo etfects. 7

Another object of my invention is to provide a breathcontrolled electronic musical instrument in which change maybe made in the quality of the sound as represented by the amplitude ratio of fundamental tone to harmonic overtones not only during the production of an individual note but also between notes played in rapid succession. A further object of my invention is to provide a breath-controlled musical instrument which is keyboard actuated but in which an infinite variety of frequency modulation vibrato effects may be produced and in which limited glissando effects may also be achieved.

Other and further objects of my invention will appear from the following description.

In general my invention contemplates the provision of a keyboard-controlled oscillator for generating a fundamental tone of constant amplitude. An overtone of constant amplitude is obtained by a circuit for multiply- 3,166,622 Patented Jan. 19, 1965 ice ing the fundamentalfrequency. A signal representative of breath pressure is obtained from a capacitance bridge which becomes unbalanced as a function of a musicians breath pressure or velocity. This signal is coupled to three component circuits. First, it is impressed upon two variable-gain stages to simultaneously control the amplitudes of the fundamental and the harmonic overtone. Second, it is coupled to a phase-lead or differentiating circuit, the output of which is coupled to the variable-gain stage associated with the harmonic overtone to vary the ratio of the intensity of the fundamental tone to that of the harmonic overtone. Third, it is coupled to a phase-lead or diderentiating circuit through which it varies the pitch both of the fundamental tone and of the harmonic overtone by the same ratio. The outputs of the two variable-gain stages are combined to energize a loudspeaker or other transducer.

The accompanying drawing is a schematic view showing an embodiment of my invention in which, for purposes of clarity, only one harmonic overtone has been provided.

Referring more particularly now to the drawing, I have provided a conventional keyboard indicated generally by the reference character 49. For purposes of clarity, keyboard 49 spans only one octave ranging from C to B and includes the five black keys, thus providing twelve semitones. Keyboard 49 controls twelve switch armatures indicated generally by the reference character 48 and including armature 48E associated with key 49E and armature 48B associated with key 4913. Each of the twelve armatures 48 is adapted to engage an associated pair of contacts indicated generally by the reference character 46. More particularly armature 48B is adapted to engage the pair of contacts 46B; and armature 48B is adapted to en gage the pair of contacts 46E, Armatures 48 normally do not engage any of the pairs of contacts 46. In the position shown only key 49E is depressed. Thus armature 48E engages the pair of contacts 46E. All the other armatuncs 48 do not engage the pairs of contacts 4-6; hence armature 4833 does not engage the pair of contacts 46-13. The negative terminal of a source of potential, such as battery 1, is grounded. The positive terminal of (battery 1 is connected through a plate resistor 4 to the plate of an oscillator triode indicated generally by the reference character 2. 'The cathode of triode .2 is connected through anonlinear resist-or, such as a lamp 8, to ground. The plate of triode 2 is connected through a capacitor 6 to a conductor 38. I provide a transformer having a nonlinear iron core tltl which couples a winding 12 and a winding 1-4. Conductor 38 is connected to one terminal of winding 12. The other terminal of winding 12 is connected to the grid of triode '2. Winding 12 is provided with a tap 16 which is connected to ground. The inductance of winding 12 may be varied as, for example, by moving the nonlinear iron core 10, The positive terminal of battery 1 is connected through winding 14 to the plate of a constant cur-rent triode indicated generally by the reference character 18. The cathode of triode '18 is connected through a cathode current resistor '20 to ground. The positive terminal of battery 1 is connected through a plate resistor 32 to the plate of a frequency doubling triode indicated generally by the reference character 30. The cathode of triode 30 is grounded. Conductor 3 8 is connected through the parallel combination of a grid leak resistor 28 and a capacitor 29 to the grid of triode 30. The plate of triode 30 is connected through a capacitor 34 to a conductor 4-0. Conductor 40 is connected through an inductor 36 to ground. One contact of each of the pairs of contacts 46 is connected through a capacitor indicated generally by the reference character 42 to conductor 38. The other contact of each of contacts 46 is connected serially through first a capacitor indicated generally by aneaesa the reference character 44 and then a resistor indicated generally by the reference character 45 to conductor 4%. It can be seen that the pair of contacts 46E are coupled by

capacitors

42B and 44B to conductors 38 and 40,

' respectively, and that the pair of contacts 463 are coupled by

capacitors

42B and 44B to conductors 38 and 41 re spectively. Each of the armatures

4s including armatures

48B and 48B is connected to ground. Conductor 38 is connected to one input of a variable gain circuit 86. Conductor 40 is connected to one input of a variable gain circuit 88. The output of circuit Se is connected through aresistor 90 to the input of a power amplifier 96. The output of circuit 88 is connected through a variable resistor 92 to the input of power amplifier 96. The junction of resistors 90 and 92 is connected through a variable resistor 94 to ground. The output of power amplifier 96 is coupled to a loudspeaker 98. One terminal of an oscillator 56 is connected to ground. The other terminal of oscillator 56 is connected to the grid of a nominally balanced phase-splitting triode indicated generally by the reference character 58. The plate of triode 58 is connected through a plate resistor 64 to the positive terminal of battery 1. The cathode of triode 58 is connected through a cathode resistor 62 to ground. Plate and

cathode resistors

64 and 62 may have approximately equal resistance values. The plate of triode 58 is connected through a bridge capacitor '54 to the input of an implifier 68. The cathode of triode 58 is connected through a variable bridge capacitor 52 to the input of amplifier 68. Capacitor 2 comprises a pair of plates one of which is elastically mounted to move in response to ram air pressure. Variable bridge capacitor 52 acts as an air-speedmeter, the elastically mounted plate moving an amount proportional to the static value of ram air pressure. Variable air speed capacitor 52 is enclosed in a metallic case 5 1 which is provided with a Pitot tube aperture through which ram air pressure is communicated to affect the capacitance of capacitor 52. Metallic case 51 is grounded, thereby to shield capacitor 52 and prevent any electrical discharge to the lips or face of a musician. The capacitance value of capacitor 54 may be approximately equal to that of condenser 52 in its quiescent state. Oscillator 56 may be tuned to a sufiiciently high frequency that the reactances of bridge capacitors 52 and 5'4 are negligible compared with the input impedance of amplifier 68. Preferably the frequency of oscillator 56 should be above the extreme limit of human hearing. Accordingly, oscillator 56 may be tuned to 100 kilocycles. The output of amplifier 68 is connected to ground through a DC. reference inductor 70; -If desired, a shunt capacitor may be used to tune inductor 70 to resonance at 100 kilocycles. The output of amplifier 68 is also connected to the anode of a detector crystal 74. The cathode of crystal 74 is connected to ground through a peak-value filter comprising the parallel combination of a capacitor 76 and a potentiometer 77. The cathode of crystal 74 is connected to the gain control input of circuit 86 and is connected through a resistor 84 to the gain control input of circuit 88, *Potentiometer 77 is provided with a slider 27 which is connected through a capacitor 26 to the grid of constant current triode 18. The grid of triode 518 is connected forwardly through a crystal 22 to ground and is also connected through a variable resistor *24 to ground. The cathode of detector crystal 74 is connected to one plate of a capacitor 78. The other plate of capacitor 78 is connected through a variable resistor 82 to the gain control input of circuit 88 and is connected through a variable resistor 30 to ground.

In operation of my breath-controlled electronic musical instrument, oscillator 2 provides the fundamental tone, the frequency of which is governed by the tank circuit comprising the inductance of winding 12 and. the capacitance of one of capacitors 42. Since, in the position shown, it is key 49E which is depressed causing armature 48E to connect the pair of contacts 46E to ground, capacitor 42E governs the frequency of oscillator triode 2. Cathode lamp 8 should have an appreciable positive temperature coeiiicient of resistance so that it reduces variation in the amplitude of oscillation. Furthermore, the negative feedback afforded by cathode lamp 8 enables triode 2 to operate in a linear region which, in combination with tank circuit inductor 12 of high Q, gives the oscillator good frequency stability. The grid voltage of constant current triode 13 will vary very slowly compared with the frequency of oscillation of triode 2; and hence, at least over a few cycles of the fundamental frequency generated by triode 2, the grid voltage of triode 18 may be considered constant and normally at ground potential. The quiescent magnitude of the current through triode 18 should reduce the incremental inductance of Winding 12 by approximately 12 percent from its normal value due to the partial saturation of the nonlinear iron core ltl. It will be appreciated that increasing the number of turns of winding 14 and decreasingthe resistance value of cathode resistor 20 will produce more saturating ampere-turns upon the nonlinear iron core 10. The pitch-frequency voltage of tank 'circuit inductor 12 is coupled to winding 14 causingthe plate of triode 18 to vary in potential. However, since the,

negative feedback cathode resistor 20 causes a change in grid to cathode potential upon any change in plate current of triode 18, the plate impedanceof tube 18 is substantially infinite; and the pitch-frequency alternating current component of plate current in tube 18 is very small. Thus the loading effect of the constant current tube 18 upon tank circuit inductor 12 is small; and negligible reduction in Q results. As will be appreciated by .those skilled in the art, the grid of frequency doubling triode 30 cannot be driven positive without drawing appreciable grid current. The provision of the well-known grid leak resistor 23 and capacitor 29 prevents the grid from being driven positive. It is desired that the plate current of triode 30 contain a considerable second harmonic component. Thus the peak-to-peak output voltage of oscillator 2, appearing on conductor 38, should be sufficiently large to drive the grid of tube 30 well be low cutoff. The wave form of plate current of tube 30 will comprise pulses occurring on the peak positive excursions of conductor 38. The second harmonic is extracted by the tank circuit comprising inductor 36 and one of the key-controlled capacitors 44. It is probably desirable to use an equally tempered scale with a constant frequency ratio between semitones of 1.0595, since there are twelve semitones per octave, and an octave rep resents a frequency ratio of 2, and (1.0595) =2. Accordingly, since the resonant frequency of a tank circuit is proportional to the square root of the reciprocal of the product of inductanceand capacitance values, if capacitor 42B has a capacitance value 1, then the capacitor 42 corresponding to the black key representing both A sharp and B flat should have a capacitance value of (l.0595) =1.l226. Similarly capacitor 42E should have a value of (1.0595 =2.25; and capacitor 420 should have a value of (1.0595 =3.56. Thus a capacitor 42 for generating a note one octave below that generated by capacitor 423 should have a capacitance value of 4. The capacitance values of each of capacitors 42 must be precisely adjusted to tune the instrument so that the same frequency ratios will result from the depression of adjacent keys. These same capacitance ratios also obtain for the capacitors 44. However, since capacitors 44 tune only the tank circuit of frequency doubling triode 30, it is not necessary that the values. of these capacitors be precisely adjusted. It will be appreciated that the tank circuit including inductor 36 will extract the second harmonic even though tuned only approximately to this fre quency. If the Q of the tank circuit including inductor 36 is not too high, then there will be appreciable band width; and the amount of second harmonic extracted will remain substantially constant despite appreciable error in the value of tuning capacitors 44.

The ram pressure of a musicians breath upon capacitor 52 will cause an increase in capacitance value by virtue of the resultant reduction in the space between the plates. The musician may exert this air velocity ram pressure either by merely blowing or by pursing the lips to whistle in accompaniment to the music played. Of course, it is the static value of ram air pressure which affects capacitor 52 rather than the whistling sound which may accompany it. It is desired that the bridge output voltage at the input of amplifier 68 increase with increase in breath pressure or velocity. Accordingly, the values of

resistors

62 and 64 and of capacitor 54 should be such as to insure that the bridge output voltage, in the absence of breath pressure, is either zero or a small voltage of the same polarity as that appearing at the cathode of phasesplitter 58. With increasing breath pressure the bridge output voltage should increase in magnitude and have the same polarity as the cathode of tube 58. It will be appreciated that, if, in the quiescent condition, the bridge output voltage were a voltage of the same polarity as the plate of tube 58, then, with increasing breath pressure, the bridge output voltage would first decrease to zero and then increase. Such effect would be very disconcerting. Hence to obviate any possibility of such undesirable effect, the bridge may be slightly unbalanced in the absence of breath pressure so that the bridge output voltage will be small but of the same polarity as that across the cathode resistor 62. The time-constant of the peak-value filter comprising capacitor 76 and potentiometer 77 is selected with regard to the usual design considerations for a detector operating at a carrier frequency of, for example, 100 kilocycles which produces intelligence at frequencies not exceeding 100 cycles per second. The detector need not respond to frequencies greater than 100 cycles per second.

With the key 49E depressed and the musician exerting a constant breath pressure, the cathode output voltage of detector crystal 74 will be constant causing

variable gain circuits

86 and 88 to provide outputs of the fundamental tone and the octave overtone respectively, which are likewise of constant amplitude.

Variable gain circuits

86 and 88 may comprise remote cut-oft pentodes or other nonlinear devices well known to the art.

Variable gain circuits

86 and 88 of course have inherent nonlinearity; but the harmonic distortion introduced will be negligible compared with that of the octave harmonic overtone intentionally introduced. In any event, distortion introduced by variable gain circuits S6 and 83 cannot be of the unmusical and undesirable intermodulation or sum and-difference frequency type, since only a single frequency, or single set of harmonically related frequencies, is impressed on each of these circuits. The steady state ratio of the fundamental tone to the second harmonic overtone may be varied by adjustment of resistor 92. The variable resistor 94 is a gain control and determines the volume output of loudspeaker 98 for a predetermined level of breath pressure of capacitor 52 so that the musician may accommodate variations in'acoustical environment to his usual range of breath pressure.

'Since the loudness signal at the cathode of detector '74 is applied both to variable gain circuit 86 and through resistor 84 to variable gain circuit 88, substantially the same tonal quality will result whether the musician exerts a strong or weak constant breath pressure to produce loud or soft tones.- The differentiation circuit comprising capacitor 78 and resistor 80 provides a voltage across resistor 80 representative of the rate of change of breath pressure. This voltage is coupled through resistor 32 to variable gain circuit '88. Thus upon a rapid variation of breath pressure accompanying either attack or decay or upon a tremolo in breath pressure, the magnitude of the harmonic overtone will rise and fall above and below its normal quiescent ratio relative to the fundamental tone. Hence during an increase in breath pressure the quality of .tone will be apparently more shrill or treble due to the increased ratio of the overtone to the fundamental, while during a decrease in breath velocity the tonal quality will be more mellow or bass due to the decrease in ratio of the overtone to the fundamental. This particular polarity of the change in quality effect closely simulates that of traditional woodwind musical instruments. The particular polarity of the change in quality effect shown and described is for purposes of illustration and not to be taken by way of limitation. The time-constant of this change in quality may be varied by adjustment of resistor and the magnitude of this change in quality may be varied by adjustment of resistor 82. In order that cross-coupling between these two adjustments be minimized, it is desirable that the maximum value of resistor 80 be less than onetenth the minimum value of resistor 82. Furthermore, amplifier 68 should have an output impedance which is less than one-tenth the minimum value of resistor $0.

I further provide for vibrato in order to make my instrument capable of more musical expressiveness. From the standpoint of the person playing my instrument, the method of producing vibrato is closely similar to that employed in the playing of a flute or recorder. In these instruments, the player produces vibnato by causing his breath pressure to fluctuate at a frequency in the range of approximately 1 to 10 cycles per second. The acoustical etfect is a. corresponding fluctuation in both pitch and loudness of the tone being played.

A person playing my instrument can produce a similar vibrato by fluctuation of his breath pressure. Furthermore, by adjustment of controls he can vary the magnitude of the pitch fluctuation which accompanies a given loudness fluctuation, and he can make the pitch fluctuat-ion symmetrical or asymmetrical.

For the following explanation, it will be assumed that the vibrato pitch variation is desired to be asymrnertical and principally downward; that is, when A at 440 cycles per second is to be played with vibrato, the frequency is desired to swing well below 440 cycles but not much above it. In subsequent explanation, it will be shown how these characteristics of the vibrato can be changed.

The cathode output signal of detector 74 is impressed upon potentiometer 77. For a fluctuation in breath presssure, then at slider 27 in addition to the DC voltage representing the average intensity of breath pressure, there will also appear an A.C. voltage proportional to the magnitude of fluctuation. These two components of voltage are irnpressd on one plate of capacitor 26. Since the other plate of capacitor 26 is connected forwardly through crystal 22 to ground, rectification occurs when the grid of constant current tube 18 extends to be driven above ground potential. Capacitor 26 will be charged to a voltage somewhat less than the peak value of the A.C. voltage representing breath fluctuation. Hence accompanyingfluctuation in breath pressure, the grid volt- .age of constant current tube 18 will vary cyclically about an average voltage which is less than ground potential an amount roughly proportional to the magnitude of the fluctuation. When the grid of constant current tube 18 is driven negatively, less saturating current will flow through winding 14; and the incremental inductance of winding 12 will increase. An increase in the value of tank circuit inductance 12 will cause a reduction in the frequency of oscillator 2. Consequently, a fluctuation in breath pressure will cause a variation in the frequency of oscillator 2 about a mean value which is less than correct pitch frequency for a tone not frequency modulated. The vibrato variationin pitch may extend over a range as much as a semitone representing.

a frequency reduction of 5.95 percent. Since the resonant frequency of a tank circuit is .equal to the reciprocal of the product of the square root'of inductance and capacitance, it is necessary to increase the inductance by approximately 12 percent in order to achieve a 6 percent reduction in frequency. This is the reason for selecting the number of turns of Winding 14 and the resistance value of cathode resistor 24) such that the incremental inductance of Winding 12 is reduced from its normal value by approximately 12 percent. It will be noted that there is no need to simultaneously change the resonant frequency of the doubler tank circuit including inductor 36. The change in frequency caused by the change in current through saturating winding 14 will causethe doubler tank circuit comprising inductor 36 to be detuned from resonance. In order that this will not appreciably change the ratio of fundamental to second harmonic, the Q of inductor 36 should be sufficiently small that the band-width of the frequency doubler tank circuit will be large enough to accommodate the 6 percent frequency change. The magnitude of the vibrato frequency variation may be varied by adjustment of slider 27. The time-constant of capacitor 26 and resistor 24 for the vibrato effect may be varied by adjustment of resistor 24. In order that there be little interaction between these two adjustments, the maximum value of the impedance seen at the slider 27 looking toward potentiometer 77 should be less than one-tenth the minimum value of resistor 24.

If the musician sharply increases his breath pressure,

as in a rapid attack, capacitor 26 will tend to be charged nearly to the potential representing this increased volume, because of the forward rectification current through crystal 22 when the grid of tube 18 is driven slightly positive; and the frequency will not appreciably increase. However, if the musician sharply decreases his breath pressure, as in an extremely rapid decay, the voltage across capacitor '26 cannot immediately change. The g'rid-of'constant current tube 18 will be driven negatively, reducing the current through winding 14; and the resultant increase in inductance of winding 12 will cause a reduction in the pitch not only of the fundamental tone but also of the harmonic overtone. If the breath pressure is held constant at the reduced intensity, current through resistor 24 will charge capacitor 26, returning the grid of constant current tube 18 to ground potential. The increase in current through winding 14 decreases the induc'tance of winding 12 and produces an increase in pitch tothe normal value. This rise in pitch follows the expo nential rise in voltage at the grid of constant current tube 18 and creates a g'lissando effect in which the pitch slides from slightly below the correct'value-to the correct value.

From the preceding explanation it can be seen that it is easy to change the characteristics of the vibrato provided by my instrument. If it is desired to reduce the asymmetry of vibrato frequency variation, a resistor 23 can be inserted in series with crystal 22 between the grid of tube 18 and ground. As Will be understood by those skilled in the art, such series resistor reduces the rectification efficiency of the crystal and thus reduces the D.C.'v"oltage developed across condenser 26 by AC. voltage at slider '27. If it is desired to reverse the asymmetry of vibrato frequency variation so that the frequency variation is principally above rather than below the true pitch, the connections to the crystal cathode and anode can beinterch-anged.

Thus my instrument provides for a vibrato which is sir'n'il'ar to flute vibrato in that pitch variations are included. In addition, my instrument provides for control of fundamental properties of these variations.

The most generally accepted standard of musical pitch is 440 cycles per second for A above middle C which results in a frequency of 261.6 cycles per second for middle C. However, some musical instruments may be tuned to a middle C of 256 cycles per second which reresults in 258 cycles per second for middle C.' In order to accommodate these variations in standard tuning and to enable my electronic musical instrument to be tuned to the same frequencies as accompanying instruments, the normal inductance of tank circuit inductor 12 is variable by movement of the nonlinear iron core It} as is Well-known tothe ant. In order that the frequency doubler triode 3d may accommodate not only a change in frequency due to the vibrato effect but also a change in frequency due to movement of iron core It), the Q of the doubler tank circuit should be less than l0. This will give the frequency doubler a bandwidth of at least 10 percent. In order to achieve a constant doubler tank circuit band-width over the entire frequency range spanned by the keyboard. I may provide a plurality of loading resistors associated with respective capacitors 44. I have shown loading resistors 45 to be connected in series with capacitors 44 to conductor 40. Resistor 45B is connected in series with capacitor 443 to conductor 40; and resistor 45E is connected in series with capacitor 44E to conductor it As will be appreciated by those skilled in the art, the provision of a loading resistor 45 for each of capacitors 44 will permit of indi vidual Q and band-width adjustment for the various frequency doubler tank circuits each including inductor 36 and each being partially loaded by parallel-connected plate resistor 32.

It will be seen that I have accomplished the objects of my invention. I have provided a breath-controlled electronic musical instrument having the same responsiveness to breath pressure and the same ability to produce subtle and rapid changes in intensity of sound as any natural Wind instrument. Any envelope of attack or decay which may be produced by a skilled musician on a Wind instrument may be produced on my breathcontrolled electronic musical instrument. Anyone reasonably adept at Whistling will find no difficulty in playing my instrument. lit is merely necessary to purse the lips in order to direct a high velocity stream of air. Amplitude modulation tremolo effects are readily created by a musician. The signal representative of intensity of breath pressure is differentiated to provide a signal enabling a change in the tonal quality by variation of the ratio of the fundamental to the harmonic overtone. This change in quality produces a pleasant and natural effect, lending variety to the resultant sound produced. My breath-controlled electronic musical instrument also provides for a flute-like vibrato produced by fluctuation of breath pressure. The vibrato frequency variation can be controlled with respect to both its range and its asymmetry. The amount both of change in tonal quality and of vibrato is a function of the frequency and of the amplitude of the change in breath pressure, since the differentiating circuits are simple high-pass filters. Furthermore, although my breath-controlled instrument is basically keyboard actuated, sliding tone glissando effects may also be produced. My instrument is provided with manually operable controls; firstly, to change the entire tuning of. the instrument; secondly, to change the steadystate tonal quality by varying the magnitude 'ratioof harmonic content to fundamental tone; thirdly, to change the range of volume output accompanying the normal range of breath pressure; fourthly, to change the time constant of the quality variation effect; fifthly, to change the magnitude of the quality variation effect; sixthly, to change the time-constant of the frequency modulation vibrato effect; and lastly, to change the amplitude of the frequency modulation vibrato effect.

to the art may be used to vary the tonal quality and to 9 achieve a frequency modulation effect. I have shown the production of only one harmonic overtone; but other overtones can be simularly produced and controlled by breath pressure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal containing a fundamental tone and at least one overtone and having a predetermined value of ratio of magnitudes of said tones, a high-pass filter circuit, means coupling the control signal to the filter circuit, and means responsive to the filter circuit for varying the ratio of magnitudes from such value.

2. A breath-controlled electronic musical instrument including in combination means responsive to static breath pressure for providing a direct-current control signal, means providing a musical signal having a predetermined value of pitch, a high-pass filter circuit, means coupling the control signal to the filter circuit, and means responsive to the filter circuit for varying the pitch from such value.

3. An electronic musical instrument including in combination means for providing a control signal, means providing a musical signal having a predetermined value of amplitude and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, means responsive to the control signal for varying the amplitude from such value, and means responsive to the control signal for varying the ratio of magnitudes from such value.

4. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal having a predetermined value of amplitude and a predetermined value of pitch, a high-pass filter circuit, means coupling the control signal to the filter circuit, means responsive to the control signal for varying the amplitude from such value, and means responsive to the filter circuit for varying the pitch from such value.

5. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal having a predetermined value of amplitude and a predetermined value of pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, a high-pass filter circuit, means coupling the control signal to the filter circuit, means responsive to the control signal for varying the amplitude from such value, means responsive to the filter circuit for varying the pitch from such value, and means responsive to the control signal for varying the ratio of magnitudes from such value.

6. A breath-controlled electronic musical instrument including in combination a capacitor having a capacitance value which is variable in response to static breath pressure, a bridge circuit including the capacitor, an oscillator, means including the oscillator for exciting the bridge circuit, means providing a musical signalhaving predetermined characteristics of amplitude and of pitch and of overtone content, and means responsive to the circuit for varying at least one of said characteristics of the musical signal.

7. An electronic musical instrument including in combination means providing a musical signal having a predetermined value of amplitude and a certain value of pitch, means for providing a control signal, means responsive to the control signal for varying the amplitude from such predetermined value, and means responsive to cyclic variation of the control signal for cyclically varying the pitch about a mean value which diiTers from such certain value by an amount generally proportional to the extent of cyclic variation.

8. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal having a predetermined value ot pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, a high-pass filter circuit, means coupling the control signal to the filter circuit, means responsive to the control signal for varying the ratio of magnitudes from such value, and means responsive to the filter circuit for varying the pitch from such value.

9. An electronic musical instrument including in combination means providing a musical signal having a predetermined value of pitch and having a predetermined amount of overtone content, means for providing a con trol signal, means responsive to the control signal for varying the overtone content from said predetermined amount, and means responsive to cyclic variation of the control signal for cyclically varying the pitch about a can value which differs from said predetermined value by an amount generally proportional to the extent of cyclic variation.

10. An electronic musical instrument including in combination means for providing a control signal, means providing a musical signal having a predetermined value of pitch, a unilateral impedance, and means responsive to cyclic variation of the control signal and including said impedance for cyclically varying the pitch about a mean value which differs from such predetermined value by an amount generally proportional to the extent of cyclic variation.

11. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal having a predetermined value of amplitude and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, a high-pass filter circuit, means coupling the control signal to the filter circuit, means responsive to the control signal for varying the amplitude from such value, and means responsive to the filter circuit for varying the ratio of mag nitudes from such value.

12. A breath-controlled electronic musical instrument including in combination means responsive to static breath pressure for providing a control signal, means providing a musical signal having a predetermined value of amplitude and a predetermined value of pitch, means responsive to the control signal for varying the amplitude from such value, and means responsive to the control signal for varying the pitch from such value.

13. An electronic musical instrument including in combination means for providing a control signal, means providing a musical signal having a predetermined value of pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, means responsive to the control signal for varying the pitch from such value, and means responsive to the control signal for varying the ratio of magnitudes from such value.

14. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal having a predetermined value of pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, a first high-pass filter circuit, a second high-pass filter circuit, means coupling the control signal to the first and to the second filter circuits, means responsive to the first filter circuit for varying the pitch from such value, and means responsive to the sec- 3 l and filter circuit for varying the ratio of magnitudesfrom such value.

15. An electronic musical instrument including in combination means for providing a control signal, means providing a musical signal having a predetermined value of amplitude and a predetermined value of pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, means responsive to the control signal for varying the amplitude from such value, means responsive to the control signal for varying the pitch from such value, and means responsive to the control signal for varying th ratio of magnitudes from such value.

16. An electronic musical instrument including in combination means for providing a direct-current control signal, means providing a musical signal having a predetermined value of amplitude and a predetermined value of pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, a first high-pass filter circuit, a second high-pass filter circuit, means coupling the control signal to the first and to the second filter circuits, means responsive to the control signal for varying the amplitude from such value, means responsive to the first filter circuit for varying the pitch from such value, and means responsive to' the second filter circuit for varying the ratio of magnitudes from such value.

17. An electronic musical instrument including in combination means for providing a control signal, vmeans providing a musical signal having a predetermined value of amplitude and a predetermined value of pitch and containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, means responsive to the control signal for varying the amplitude from such value, means responsive to the control signal for varying the ratio of magnitudes from such control signal for cyclically varying the pitch about a i value, and means responsive to cyclic variation of the mean value which differs from such predetermined value by an amount generally proportional to the extent of cyclic variation.

including in combination a passive impedance having an impedance value which is variable in response to static breath pressure, a bridge circuit including the impedance, an oscillator, means including the oscillatorfor exciting the bridge circuit with alternating-current, means providing a musical signal having predetermined characteristics of amplitude and of pitch and of overtone content, and means responsive to the circuit for varying at least one of said characteristics of the musical signal.

20. A breath-controlled electronic musical instrument including in combination means responsive to breath pressure for providing a control signal, means providing a musical signal containing a fundamental tone and an overtone and having a predetermined value of ratio of magnitudes of said tones, and means responsive to the control signal for varying the ratio of magnitudes from such value.

21. An electronic musical instrument including in combination means for providing an electrical control signal, means providing a musical signal containing a fundamental tone and an overtone, manually operable means for adjustably regulating the nominal value of ratio of magnitudes of said tones, and means responsive to the control signal for varying the ratio of magnitudes from such manually determined nominal value.

22. A breath controlled electronic musical instrument including in combination means responsive to breath pressure for providing a control signal, means for generating a fundamental tone signal and an overtone signal, said tone signals having a predetermined value of ratio of magnitudes, means responsive to the tone signals for providing a musical signal, and means responsive to the control signal and interposed between the generating means and the musical signal means for varying the ratio or". magnitudes from such value.

References Cited in the file of this patent UNITED STATES PATENTS 2,147,948 Kent Feb. 21, 1939 2,270,789 Smith Jan. 20, 1942 2,285,132 Weathers June 2, 1 942 2,296,125 Traub Sept. 15, 1942 2,321,370 Dubilier June 8, 1943 2,514,490 Hanert July 11, 1950 2,522,923 Bourn Sept. 19, 1950 2,580,424 Hanert Jan. 1, 1952 2,795,648 Mason June 11, 1957 2,871,745 Scott Feb. 3, 1959 2,907,244 Schreiber Oct. 6, 1959 FOREIGN PATENTS 703,733 Great Britain Feb. 10, 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,166,622 January 19, 1965 Herbert M. Neustadt It is hereby certified that'error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 10, line 30, beginning with "10. An electronic" strike out all to and including "variation." in line 38, same column 10; column 10, line 39, for "11." read l0. line 49,; for "12." read ll. line 57, for "13," read l2. line 66, for "14." read l3. column ll, line 3, for "15."

read l4. line 14, for "16." read l5. line 28, for "17 read l6 line 42, for "18." read 17. line 52, for "'19." read l8, column 12, line 10, for "20." read 19. line 18, for "21.," read 20. line 26, for "22." read 2l.

column 11, lines 37 and 38, strike 7 out "control signal for cyclically varying the pitch about a value, and means responsive to cyclic variation of the" and i. insert instead value, and means responsive to cyclic variation of the control signal for cyclically varying the pitch about a in the heading to the printed specification, line 6, for "22 Claims." read 21 Claims.

Signed and sealed this lst day of June 1965.,

(SEAL) Attcstt ERNEST W. SWIDER EDWARD J. BRENNER Officer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,166,622 January 19, 1965 Herbert M. Neustadt It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 10, line 30, beginning with '10. An electronic" strike out all to and including "variation." in line 38, same column 10; column 10, line 39, for "11." read l0. line 49 for "12." read ll. line 57, for "13." read l2. line 66, for "14." read l3. column 11, line 3, for "15." read l4. line 14, for "16." read 15. line 28, for "17." read l6. line 42, for "l8.""read l7. line 52, for "'19." read l8, column 12, line 10, for "20."

read l9. line 18, for "21." read 20. line 26,

for "22." read 21. column 11, lines 37 and 38, strike out "control signal for cyclically varying the pitch about a value, and means responsive to cyclic variation of the" and insert instead value, and means responsive to cyclic variatior of the control signal for cyclically varying the pitch about a in the heading to the printed specification, line 6,

for "22 Claims." read 21 Claims.

Signed and sealed this 1st day of June 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents