US3766305A - D.c. keyed high low select preference system for polyphonic electrical musical instruments - Google Patents

Abstract

A transistorized high-low note select system for keyboard type electrical musical instruments which provides for direct current operation with or without control of the attack and decay envelope and supplies the alternating current signals for the highest and/or lowest notes of a group of notes played together respectively to a high note lead or a low note lead or to independent leads for each. Primarily, this is for the purpose of supplying the high note signal of group of keys played simultaneously to be sounded as a solo note, or high and low notes of an accompaniment chord to be sounded in unison or with frequency division as a pair of bass notes one or two octaves down from a three or four note chord being held on a keyboard for example. The system may also be used to supply the lowest note with frequency division as a single bass note or for similar purposes. The keyboard may be conventional.

Description

United States Patent [191 Schrecongost 1 D.C. KEYED HIGH LOW SELECT PREFERENCE SYSTEM FOR POLYPHONIC ELECTRICAL MUSICAL INSTRUMENTS [75] Inventor: Ray B. Schrecongost, Park Ridge,

[73] Assignee: Hammond Corporation, Deerfield,

- Ill.

[22] Filed: July 17, 1972 [21] Appl. No.1 272,437

[52] U.S. Cl. 84/l.01, 84/DIG. 2 [51] Int. Cl. G101! 1/02 [58] Field of Search 84/1.0l, 1.11, 1.12,

84/l.17, l.l9-l.24, DIG. 2, DIG. 23; 307/23l,'233, 241-243 [56] References Cited UNITED STATES PATENTS 2,429,226 10/1947 I-Ianert 84/l.2l 2,468,062 4/1949 I-lanert..... 84/1.2 2,645,968 7/1953 I-lanert 84/l.22 2,933,004 4/1960 Hanert 84/1.0l 3,051,032 8/1962 I-lanert 84/1.19 3,283,057 11/1966 Campbell 84/1.0l 3,476,864 11/1969 Munch et al.... 84/D1G. 2 3,511,917 5/1970 Mallett 84/1.0l 3,538,804 11/1970 George 84/l.0l 3,665,089 5/1972 Stearns 84/l.0l 3,719,767 3/1973 Matumoto et a]. 84/l.01 2,710,555 6/1955 Martin 84/l.01 2,874,286 2/1959 Bode 84/DIG. 2

[ Oct. 16, 1973 Primary Examiner-Richard B. Wilkinson Assistant ExaminerStanley J. Witkowski AttorneyWilliam F. Gradolph et a1.

[5 7 ABSTRACT A transistorized high-low note select system for keyboard type electrical musical instruments which provides for direct current operation with or without control of the attack and decay envelope and supplies the alternating current signals for the highest and/or lowest notes of a group of notes played together respectively to a high note lead or a low note lead or to independent leads for each. Primarily, this is for the purpose of supplying the high note signal of group of keys played simultaneously to be sounded as a solo note, or high and low notes of an accompaniment chord to be sounded in unison or with frequency division as a pair of bass notes one or two octaves down from a three or four note chord being held on a keyboard for example. The system may also be used to supply the lowest note with frequency division as a single bass note or for similar purposes. The keyboard may be conventional.

7 Claims, 1 Drawing Figure D.C. KEYED HIGH LOW SELECT PREFERENCE SYSTEM FOR POLYPIIONIC ELECTRICAL MUSICAL INSTRUMENTS BACKGROUND OF THE INVENTION 1. Field of the Invention High and/or low note select systems for keyboard type electrical musical instruments and instruments which incorporate such systems.

2. Description of the Prior Art Keyboard type electrical musical instruments, such as electric or electronic organs, for example, have for a number of years incorporated what is referred to generally in this technology as preference circuits. For example of such typical instruments and preference systems see .I. M. Hanert, US. Pat. Nos. 3,051,032; 2,933,004; 2,468,062; 2,429,226; and 2,645,968. For a more modern instrument using such a system see Tennes and Kern US. Pat. No. 3,567,838 and for a high-low note preference system which it is believed is the prior system most similar to the present invention, see H. E. W. Bode, US. Pat. No. 2,874,286 which is incorporated by reference in the Tennes et al., US. Pat. No. 3,567,838, referred to above.

For purpose of orientation, the present invention may be considered as an improvement over the system of Bode, U.S. Pat. No. 2,874,286 and as a substitute therefor, for example, in musical instruments of the type of Tennes et al. U.S. Pat. No. 3,567,838.

SUMMARY OF THE INVENTION Briefly, the system of the previously referred to Tennes et al patent provides a keyboard type musical instrument in which holding the keys of a chord of three or four notes with the left hand supplies the appropriate three of four note signals together to a chord lead. Simultaneously, a preference system of the Bode type supplies the signal for the lowest note of the group to a low note select lead and the signal for the highest note of the group to a high note select lead. An automatic rhythm system of the type which sounds drum, cymbal, blocks, and similar untuned sounds according to any of several selected programs is connected such that at appropriate intervals during the program which may include various of the untuned instrumental sounds, the programmer also sounds whatever signals are on the chord lead, the low note select lead and the high note select lead. Usually, the signals on the low note select lead and the high note select lead are passed through one or preferably two stages of binary frequency division so that the selected low and high notes sound one or preferably two octaves down from the chord. Overall, therefore, the effect is such that by simply holding the keys for a three or four note chord with the left hand, and at appropriate times changing from one chord to another, the system automatically according to whatever program is selected, keys orsounds the chord, a low bass note and a high bass note. This eliminates the need to play the chord at the proper time and also eliminates the need for bass pedals and the skill normally required for their actuation.

The previously referred to Bode preference system is based upon what is known as A.C. keying, that is, the playing key contacts make and break the alternating current signal circuits. There are disadvantages associated with A.C. keying, such as problems'with transients and particularly an inability to exercise control over the keying envelope. There is no convenient way for sustaining the tone with a gradually decaying envelope after a key has been released, for example. The present invention overcomes such problems by providing a D.C. actuated preference circuit. That is, the playing keys make and break a D. C. circuit which turns transistors on and off with or without sustain as desired. For instance, the control D.C. can charge a capacitor which will hold the signal circuit through the preference network on long enough to allow percussion or sustain keying in a following circuit. Thus, the substitution of DC. actuation or keying for A.C. keying permits the designer to exercise envelope control which is not possible with A.C.keying.

Additionally, the provision of D.C. acutation makes it possible to design an organ system such that each of the playing keys needs only one set of make contacts. These make a DC. control circuit for the particular key and this control circuit can be routed to any number of keyers for various different purposes. Thus, DC. control signals for a group of keys played together supply note signals for the lowest, the highest or both notes of the group. These selected note signals, with or without sustain, can be frequency divided, multiplied, formanted and can have any desired envelope characteristic provided by a following percussive or sustain keyer.

These and other advantages of DC. operation are well appreciated in this art and D.C. keyers are in general use. So far as is known, however, the application of DC. operation to preference circuits has not previously been successfully accomplished.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. ii is a circuit diagram of a preference system which includes features of the present invention; and

FIG. 2 is a diagram showing the circuit of FIG. I modified to provide sustain of the envelope after a playing key has been released.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I of the drawings a group of transistors are indicated individually at A, B, C, I), N. Each of these is the active element of a keyer or gate for one note of the portion of the musical instrument to which the preference system of the invention is applied. For example, the preference system may be applied to the accompaniment section of an organ and cover the lowest group of twenty playing keys, such that if a chord of three or four keys is played within this section, the preference system will select the lowest and the highest notes of any such chord.

The transistors A-D may be considered representative of the lowest four keyers for this section and N the highest, it being understood that there will be others between D and N which are not shown since all are identical.

The base of transistor A is connected to ground, which here represents the other side of the circuit, through a resistor and through resistor 12 to one side of a set of playing key contacts 14, the other side of which is connected to a DC. keying bus 16. Branch loads 15 are the main keying leads for connection to the other customary organ keyers, not shown which key the noteto be played in the usual organ fashion, that is, in any of the regular organ modes. The emitter is connected to ground through a resistor 18 and to a terminal 20 which may be considered as the source of the particular music signal to be keyed. Each of these terminals, 20, is connected to one side of the appropriate tone signal generator. The other side of each generator, as is customary, is connected to the other side of the circuit, normally referred to as ground. One of these generators, (all are alike excepting for frequency) for the F signal, is indicated at 21. All of the tranisitors A'N are similarly connected excepting that the frequencies applied to terminals 20 are a semitone apart as indicated by the designations F,, F F F F Similarly also, the playing key contacts 14 are actuated by different playing keys, each of which is appropriate to its particular tone signal.

The transistor A, for keying the lowest note of the group, has its collector connected through a resistor 22 to a low note select output terminal 24, connected in turn to the input of a preamplifier 26 having an output The collector of the second transistor B, is connected to the collector of A through a resistor 28 and to the collector of C through a resistor 30. C collector is also connected through a resistor 32 to the collector of D which is connected to the collector of the next in the series'through resistor 34, and so on to the collector of transistor N, the last in the series. The collector of transistor N is connected through resistor 36 to a high note select output terminal 38. This output terminal is connected to the input of preamplifier 40 having an output 41.

Suitable values for the constants of this particular circuit are as follows. Resistors 10, 10 K; resistors 18, 100 ohms; resistors 12, 100 K; and resistors 22, 28, 30, 32, 34 and 36, 22 K. The keying voltage on bus '16 may suitably he -28 v.

The preamplifiers 26 and 40 have a relatively high input impedance of the order of ten times or more of the total of the resistance in the line between the two output terminals 24 and 38. If, as in the example given, there are twenty keyers, and, therefore, 21' resistors in series of 22 K each, a total of 462 K,a suitable value for the input impedance of the amplifiers is megohms or so. v

The outputs 27 and 41 from the preamplifiers may be connected to any desired circuits such as frequency dividers and suitable formants to'obtain bass notes re- .lated to the chord being held for example.

automatic programmer can at appropriate intervals switch the preamplifier outputs to a bass note frequency divider leading to the output system of the organ or if desired, the programmer or a multivibrator or some similar system can switch the low and high terminals 24 and 38 to the input of a single preamplifier. It will be appreciated, of course, that this invention is concerned with the preference system and not particularly with the specific use made of the high and low note signals selected by the system,

The system operates as follows. Assuming the playing key contacts 14 are closed for transistor A, this applies the -28 v. on bus 16 to the to one voltage divider composed of 100 K resistor 12 and I0 K resistor 10. The voltage appearing at the base' of transistor A is, therefore, about -2.8 v. which causes the transistor to conduct. The portion of the F,signal at terminal not grounded through resistor 18 is therefore conducted to the junction between resistors 22 and 28. Because of the high impedance of the amplifiers 26 and 40, it makes little difference whether the signal passes through resistor 22 to amplifier 26 or whether it passes through twenty resistors of the same value to amplifier 40. In one case the resistance is 22 K whereas on the other it is 440 K, but both are small as compared with the amplifier input impedances of 5 megohms or so. THe F, signal from terminal 20, therefore, appears at both preamplifier output terminals 27 and 41 at about the same strength.

If new it is assumed that key contacts 14 are closed for signals F, and F,,, (transistors A and N) the F, signal appears at terminal 24 through resistor 22 (22 K) and signal F appears at terminal 38 through resistor 36 (22 K). Also, the F, signal passes through the group of resistors 28, 30, 32, etc. to appear at the junction of resis for 36 with the lead to the collector transistor N. Since the resistance from this point to terminal 38 is 22 K (resistor 36) and transistor N is conductive. and the resistance 18 to ground is only ohms, the F, signal is attenuated approximately by the ratio 100 plus the resistance of the transistor divided by 22,000. This is sufficient to attenuate the F, signal appearing at terminal 38 such that it is completely masked by the F signal. Similarly, the F signal to terminal 24 is essentially grounded through transistor A and its resistor 18. The high note signal, F therefore, appears at terminal 41 and the low note signal at terminal 27.

If a three or four note chord is held, those signals supplied to the output group of series connected 22 K resistors anywhere between the highest and the lowest note signals of the chord will be effectively grounded for practical purposes through the transistors and resistors 18 of the highest and lowest transistors of the group which have been made conductive-by closing their key contacts 14. Thus, regardless of'the number of keys held simultaneouly, only the note signal for the lowest of the group will appear at terminal 27 and only the signal for the highest key held will appear at terminal 41. It should be noted that whether a keyed signal appears at the output or not is determined without affecting the impedance of the DC. keying circuits involved, or the impedance of the signal sources, and that the impedance to the other side of the circuit through low value resistors 18 is essentially independent of the impednace of the signal generators connected between terminals 20 and the other side of the circuit.

The modified arrangement of FIG. 2 shows the circuit of a single transistor and is like those of FIG. ll excepting that a capacitor 50, shown connected across resistors 10 and 12, will remain charged after key release. A similar capacitor is connected across each of the other pairs of resistors 10 and 12 of the preference circuit. With this modification, closing key contacts 14 charges the capacitor 50 and turns on the transistor. When the playing key is released and the contacts open, capacitor 50 will remain charged, and consequently the note signal will remain on, long enough for subsequent gating or envelope shaping of the output signal or the frequency divider outputs by means of a conventional unitary keying system. A- conventional snubbing circuit may be required to insure that only the last-played note remains on. As an example, the preference system with this simple holding circuit can have the preamplifier outputs connected through unitary keyers, which may be conventional. These following unitary keyers can give the selected notes any desired envelope characteristic such as percussive (a struck or plucked string effect) or sustain (a gradual decay after the key is released) or something similar, the purpose of the capacitors 50 being to hold the note after key release long enough for the unitary keyers to impart their characteristic envelope. This simple holding feature for the preference circuit is illustrative of the possibilities for control of the keying envelope which is characteris tic of this invention and one of its important features.

With an appropriate adjustment of values, the transistors shown may be any of several types including field effect transistors if desired.

Although the preference circuit of this invention has been described in conjunction with a system which selects both the high and low notes of a group of keys played together, it will be appreciated that the system somewhat abridged can supply only the high or the low note if that is all that is desired. For example, if only the high note is needed, the low end portion of the circuit including the resistor 22, terminal 24 and preamplifier 26 can be eliminated. It will also be appreciated that even though emphasis has been placed upon use of the system to supply high and low bass notes, this is for the purpose of illustrating a typical embodiment. As mentioned earlier, preference circuits have other uses and it is considered that the invention is in the D.C. preference circuit itself, rather than in the uses to which the output of the circuit is put.

, I claim:

I. In a preference system, a plurality of sources for a group of alternating current signals, a plurality of actuated control elements one for each of said signals, a plurality of transistors, one for each of said signals, a source of D.C. keying potential, D.C. circuit means including said control elements connected individually from said D.C. source to said transistors to cause individual transistors to conduct when aappropriate individual control elements are actuated,veach of said transistors having an input circuit connected to receive a signal from one of said sources and an output, an output line consisting of a group of series connected substantially identical resistors with one end of said group connected to a terminal, the outputs of said transistors being connected individually to the junctions between said resistors, high impedance output circuit means connected to said terminal, each of said input circuits for said transistors having a low impedance connection in shunt with its signal source, the impedance of said high impedance output circuit means being many times the total impedance of all of the series connected resistors and the impedance of each of said series connected resistors being many times the impedance of each of said low impedance connections.

2. The system of claim I in which each of said input circuits includes a low impedance resistor connected between the transistor signal input and ground.

3. The system of claim 1 including sustain circuits for said transistors for retaining said transistors in conducting condition for a selected period after said control elements are deactuated, each of said sustain circuits including a capacitor connected to be charged when the control element is actuated and to discharge at a controlled rate when the control element is deactuated.

4. In a high-low note select preference system, a plurality of sources for a group of musical tone signals, a plurality of playing keys one for each of said signals, each of said keys having a contact set, a plurality of transistors, one for each of said signals, a source of D.C. keying potential, D.C. circuit means including said contact sets connected individually from said D.C. source to said transistors to cause individual transistors to conduct when appropriate playing keys are actuated, each of said transistors having a signal input circuit connected to receive a signal from one of said sources and an output line consisting of a group of series connected substantially identical resistors with the first of said group connected to a low note select terminal and the last of said group connected to a high note select terminal, said group of resistors having one more resistor than there are transistors, the output of the transistor for the lowest note of the group being connected to the junction between the first and second resistor, the output form the transistor for the next higher note being connected to the junction between the second and third resistor, the output from the transistor for the next higher note being connected to the junction between the third and fourth resistor and so on for the outputs of all of said transistors with the output of the transistor for the highest note of the group connected between the last and the next to last resistors of said group, high impedance output circuit means connected to said low note select and said high note select terminals, each of said signal input circuits for said transistors having a low impedance connection in shunt with the signal source, the impedance of said high impedance output circuit means being many times the total impedance of all the series connected resistors and the impedance of each of said series connected resistors being many times the impedance of each of the low impedance connections around the signal sources.

5. The system called for in claim 4 in which each of said signal input circuits includes a low impedance resistor connected between the transistor input and ground.

6. The system called for in claim 4 in which said D.C. circuit means includes a series resistor network and capacitor in paralled thereto connected between each said contact sets and the other side of the circuit, and an intermediate voltage point on said resistor network connected to said transistor.

7. The system called for in claim 5 in which said D.C. circuit means includes a series resistor network and capacitor in parallel thereto connected between each said contact sets and the other side of the circuit, and an intermediate voltage point on said resistor network connected to said transistor.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,766,305 Dated ctober 16, 1973 Inventor) Ray B. Schrecongost It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Abstract, line 9, before "group" insert -a--. Col. 1, line 36, "of" should be or-. Col. 4, line 9, "THe" should be I'he-;

line 18, after "collector" insert of-; line 20, should be I line 47, "impednace" should be impedance-.

Col. 6, line 17, after "output" insert an output-;

line 25, "form" should be ---from-'.

Signed and sealed this 21st day of May 197 (SEAL) Attest:

EDWARD PLFLETCHLIELJI'L. C. MARSHALL Attesting; Officer Commissioner of Patents FORM (169) USCOMM-DC 60376-P69 9 U.5. GOVEfiNMENT PRINTING OFFICE 199 0-367334.

Claims (7)

1. In a preference system, a plurality of sources for a group of alternating current signals, a plurality of actuated control elements one for each of said signals, a plurality of transistors, one for each of said signals, a source of D.C. keying potential, D.C. circuit means including said control elements connected individually from said D.C. source to said transistors to cause individual transistors to conduct when aappropriate individual control elements are actuated, each of said transistors having an input circuit connected to receive a signal from one of said sources and an output, an output line consisting of a group of series connected substantially identical resistors with one end of said group connected to a terminal, the outputs of said transistors being connected individually to the junctions between said resistors, high impedance output circuit means connected to said terminal, each of said input circuits for said transistors having a low impedance connection in shunt with its signal source, the impedance of said high impedance output circuit means being many times the total impedance of all of the series connected resistors and the impedance of each of said series connected resistors being many times the impedance of each of said low impedance connections.

2. The system of claim 1 in which each of said input circuits includes a low impedance resistor connected between the transistor signal input and ground.

3. The system of claim 1 including sustain circuits for said transistors for retaining said transistors in conducting condition for a selected period after said control elements are deactuated, each of said sustain circuits including a capacitor connected to be charged when the control element is actuated and to discharge at a controlled rate when the control element is deactuated.

4. In a high-low note select preference system, a plurality of sources for a group of musical tone signals, a plurality of playing keys one for each of said signals, each of said keys having a contact set, a plurality of transistors, one for each of said signals, a source of D.C. keying potential, D.C. circuit means including said contAct sets connected individually from said D.C. source to said transistors to cause individual transistors to conduct when appropriate playing keys are actuated, each of said transistors having a signal input circuit connected to receive a signal from one of said sources and an output, an output line consisting of a group of series connected substantially identical resistors with the first of said group connected to a low note select terminal and the last of said group connected to a high note select terminal, said group of resistors having one more resistor than there are transistors, the output of the transistor for the lowest note of the group being connected to the junction between the first and second resistor, the output from the transistor for the next higher note being connected to the junction between the second and third resistor, the output from the transistor for the next higher note being connected to the junction between the third and fourth resistor and so on for the outputs of all of said transistors with the output of the transistor for the highest note of the group connected between the last and the next to last resistors of said group, high impedance output circuit means connected to said low note select and said high note select terminals, each of said signal input circuits for said transistors having a low impedance connection in shunt with the signal source, the impedance of said high impedance output circuit means being many times the total impedance of all the series connected resistors and the impedance of each of said series connected resistors being many times the impedance of each of the low impedance connections around the signal sources.

5. The system called for in claim 4 in which each of said signal input circuits includes a low impedance resistor connected between the transistor input and ground.

6. The system called for in claim 4 in which said D.C. circuit means includes a series resistor network and capacitor in paralled thereto connected between each said contact sets and the other side of the circuit, and an intermediate voltage point on said resistor network connected to said transistor.

7. The system called for in claim 5 in which said D.C. circuit means includes a series resistor network and capacitor in parallel thereto connected between each said contact sets and the other side of the circuit, and an intermediate voltage point on said resistor network connected to said transistor.

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