Electronic musical synthesizer

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Feb 29, 1972 ... [73] Assignee: The Wurlitzer Company, Chicago,. Ill. [22] Filed: Feb. ... R. G. Hibberd, Integrated Circuits, Texas Instruments ..... leading to the amplifier 138. As will be ..... 530, and also by a capacitor 532, the value of which is.
United States Patent [191

{111 3,808,344 [451 Apr. 30, 1974

Ippolito et al. [54] ELECTRONIC MUSICAL SYNTHESIZER [75] Inventors: Anthony C. lppolito; Roger J. McNerney; Harold 0. Schwartz, all of North Tonawanda, NY.

[73] Assignee: The Wurlitzer Company, Chicago,

Electronics Series, McGraw-l-lill Book Company, copyright 1969, pp. -l-11. Primary Examiner—-Richard B. Wilkinson Assistant Examiner—Stanley J. Witkowski

Attorney, Agent, or Firm-Olson, Trexler, Wolters, Bushnell & Fosse, Ltd.

Ill.

[22] Filed: Feb. 29, 1972 [21] Appl. No.: 230,295

[57] [52]

US. Cl ................... .. 84/l.01, 84/1.17, 84/1.19,

[51]

Int. Cl. ........................................... .. GlOh 5/06

[58]

Field of Search ....... .. 84/l.0l,1.03,1.11,1.l3,

84/D1G. 22

84/1.17—l.19, 1.24-1.27, DIG. 17, DIG. 22

ABSTRACT

An electronic musical synthesizer is provided with a radio frequency master oscillator which operates

through a plurality of parallel divider paths of differ ent dividing ratios to produce oscillations correspond ing to the 12 musical notes of one octave. The divider

[56]

circuits further operate through a divide by 2 circuit

References Cited

to produce a second octave plus one of musical tone

UNITED STATES PATENTS 3,757,024

9/1973

3,051,032

8/1962

Stinson et al. ..................... .. 84/1.17 Hanert . . . . . . . . . . . . .

3,257,494

6/1966

Starck ......... ..

3,520,984

7/1970

Machanian

3,317,649

5/1967

Hearne . . . . . . . .

. . . . . . . ..

84/l.19

. 84/].27 X

84/124 . . . ..

84/].24 84/1.01

3,422,208

l/l969

Barry . . . . . . . . . . . . . . . . . . .

. . . ..

3,480,719

1 H1969

Schwartz et al. . . . .

. . . .. 84/126

3,535,429

10/1970

Uchiyama . . . . . . . .

. . . ..

84/1.01

3,553,336

1/1971

Markowitz....

3,590,131

6/1971

Reyers . . . . . .

. . . .. 84/l.03

84/].17 X

3,619,469

11/1971

Adachi . . . . . .

. . . .. 8411.17

3,672,253

6/1972

l-liyama .............................. .. 84/127

frequencies, thus providing two octaves plus one of musical tones. The tones are played monophonically from a 25 note keyboard through a pair of priority

latching networks. Further divider chains are provided which produce available notes in musical third and musical ?fth relationship to the original notes, as well as notes in octave relation thereto. Various manually

operable controls are manipulable by the musician to simulate known musical effect, and also to vary attack and decay, to vary the onset of a tone as to pitch, and

to provide various modulations, thereby producing novel musical effects.

OTHER PUBLICATIONS

R. G. Hibberd, Integrated Circuits, Texas Instruments

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ELECTRONIC MUSICAL SYNTHESTZER

control of the musician for producing a wah-wah effect as is often used in trumpet playing, and further manu

ally controllable means is provided for effecting the

In the past it has been common practice to design

shift of pitch at the onset of each tone.

electronic musical instruments in such manner as to

Various objects and advantages of the present inven

simulate or attempt to simulate known musical effects. This has been accomplished to a greater or lesser de gree of success depending on the design of an individ ual instrument. More lately, efforts have been made to synthesize musical tones of somewhat novel nature.

tion as well as circuits by means of which these are ob—

tained will be apparent from a study of the following speci?cation when taken in connection with the ac

companying drawings wherein:

Such instruments have generally been rather compli

FIG. I is a perspective view of an electronic musical

instrument constructed in accordance with the present

cated and cumbersome, and in at least many instances it has been necessary to play only one note or combina tion of notes at a time for purposes of recording, fol lowing which connections and controls are changed to allow recording ofa subsequent note or combination of notes. This has precluded live performances with the results available only as recordings. In accordance with conventional electronic instru ments, speci?cally electronic organs, it is common

practice to provide twelve master oscillators generating

invention; FIG. 2 is a block diagram illustrating the principles of the present invention; FIG. 3 is a layout of the stops and controls for the

keyboard and effects forming the present invention; FIG. 4 is a detail block diagram illustrating details of

20

the 12 semi-tones of an octave, speci?cally the highest

the present invention; FIG. 5 is another detail block diagram illustrating fur ther details of the present invention; FIG. 6 is yet another detail block diagram illustrating

octave of notes to be played on the organ, or perhaps an octave higher. Divider chains or slave oscillators

details of the present invention;

notes in descending octave relation. It has long been known in theory that a single master oscillator could be employed with parallel dividers of different ratios of di

FIG. 8 is yet another detail block diagram illustrating further aspects of the present invention;

vision to produce the 12 semi-tones of the top octave.

detail of the present invention;

FIG. ‘7 is a combination block and electronic wiring have been provided which have respectively been con diagram illustrating a portion of the present invention; trolled by the master oscillators to produce similar 25

This would have the advantage of requiring the tuning

FIG. 9 is an electronic wiring diagram illustrating a 30

of only one master oscillator, a substantial production

advantage. However, with electronic components as

they existed until recently the cost and space require ments have been prohibitive. However, with the advent of LSI (large scale integration) it has become feasible to put this theory into practice. How to handle the note

35

'

FIG. I0 is a schematic wiring diagram illustrating a speci?c part of the present invention; ' FIG. 111 is a schematic wiring diagram of the master

oscillator and related parts; FIG. I2 is a schematic wiring diagram of the steering circuit which determines which priority latching net work output will be effective; FIG. TS is a partial block and partial schematic wiring

frequencies so produced is another matter, and forms a signi?cant portion of the present invention.

diagram showing details of the modulation effect; FIG. 14 is a schematic wiring diagram illustrating the In accordance with the present invention, a single master oscillator at a high radio frequency, on the 40 percussion sections of the present invention; and FIG. 115 is a schematic wiring diagram illustrating the order of 1.5 MHz is employed. This master oscillator is attack and decay controlling circuits. applied to the input of an LSI divider chain, having a Referring ?rst to FIG. I, there is shown an electronic plurality of parallel dividers of different divide down organ 20 having a case 22 with an upper keyboard 24 ratios, whereby l2 outputs are provided having the re lation to one another of the 12 half tones of a musical 45 and a lower keyboard 26 in shortened, overlapping fashion, of the type generally known as a spinet organ. octave. The output of the LSI divider chain is applied A suitable loudspeaker system is provided behind a grill directly to a switching network, hereinafter identi?ed 28 below the keyboard, and the organ is also provided as a priority latching network, and the output is also fed to a divide by two divider stage, and on to another pri

ority latching network, whereby two octaves of fre

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with a one octave pedal board or clavier 30 and a swell

pedal 32 for controlling overall volume. In addition, and generally in accordance with conventional prac tice, the organ is provided with stop tablets 34 gener

quencies are produced corresponding to musical tones. Further divider chains are fed by the outputs of the two

ally on a level with the keyboards 24 and 26. Further, priority latching networks to produce frequencies bear ing relations to one another of musical thirds and ?fths, 55 and also in accordance with conventional practice, the organ is provided with a music rack 36. as well as octave relations. Departing from conventional practice, the organ is Various circuits are provided for controlling the at provided with a two octave plus one third keyboard 38 tack and sustain or decay time in accordance with the for producing novel effects, i.e. synthesizing. It is this desires of the musician. Means under the control of the

musician also is provided for modulating the musical tones produced by the instrument at a desired low audio rate, the rate and extent of modulation being

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keyboard and the accompanying synthesizer that form the subject matter of the present invention. Stop tablets 40 are provided to the left of the keyboard 38 for oper

ation and control of the synthesizer in conjunction with the keys. Additional controls 42 for the synthesizer are pressed beyond its normal depress position it will actu 65 provided to the right of the third keyboard 38. Attention next should be directed to FIG. 3 for fur ate a switch to produce still further effects, such as ther illustration of the stop tablets 40 and the controls modulation for as long as the key is held down, or a cre 42. As will be seen in FIG. 3, the stop tablets 49 from scendo or slide effect. Means also is provided under the

manually controllable. The keyboard is also provided

with a “second touch” whereby, when a key is de

3,808,344 3

4

the left comprise nine sine wave tablets 44 of different

Another push button 72 is provided for turning on delta pitch, the terminology being taken from mathe

footage lengths running from 16 foot through 1% foot.

matics and somewhat akin to differentiation. In partic ular, the delta pitch control allows each note played on the third keyboard to start below its nominal pitch and then to swoop up to the actual pitch, producing novel electronic effects not related to traditional instruments.

As is indicated in FIG. 3, these stop tablets comprise blue letters on a white background. Following the foot

age stop tablets 44 are three stop tablets 46 controlling filters for the usual three families of organ or orchestral

sounds, namely reed, brass, and string, omitting the organ diapason which is generally considered to be the fourth organ family. For ready distinction to the player,

One further push button 74 is provided for producing

the three stop tablets 46 comprise white printing on a

string voices of the filters controlled by the stop tablets

a wah-wah effect which is added to the reed, brass, and 46 for realistic instrumental effects, or for use in con

red background.

junction with other voices for unusual, synthesized

To the right of tablets 46 there are disposed seven

sounds. Finally, the controls 42 include a knob 76 controlling

stop tablets, comprising red print on light yellow back ground, each representing a percussive sound, as la beled in the ?gure. As will be understood, all of the stop tablets 40, including the three groups 44, 46 and 48 control filters for producing the different preset ef

a rheostat which permits the performer to adjust the overall volume of the third keyboard with any voice or combination of voices on the organ. Now that some in dication has been given as to the effects that are to be

fects indicated. More about this will be set forth later.

obtained by the third keyboard, attention is invited to Turning now to the controls 42 on the right of the 20 FIG. 2 for an illustration in block diagram form of how such effects are obtained. third keyboard, these will likewise be seen in FIG. 3,

The third keyboard is provided with a single master oscillator 78 operating at a radio frequency, speci?

wherein it will be apparent that the straight line ar

rangement of the organ keyboard, stop tablets, and controls has been broken for simplicity of illustration. Reading from the left, there ?rst will be seen a volume control 50 for the sine wave footage voices, with con

25

trols 52 and 54. The controls 52 and 54 comprise push

cally on the order 1.5 MHz. The output of the master oscillator 78 is applied to a large scale integrated cir cuit divider 80 having a plurality of divider circuits in parallel to provide an output at 82 corresponding to the 12 note frequencies of the top octave of semi-tones to

buttons, the “bright” push button 52 making the timbre

be played by the third keyboard. The divider 80 com bright by increasing the highs, and the “deep” push 30 prises a L.S.I. chip or chips sold by General Instrument button 54 making the timbre deep by increasing the Corporation, Microelectronic division of Hicksville, lows. N.Y. The divider 80 initially comprised two chips iden The next section relates to a modulator which varies ti?ed commercially by Wurlitzer Part Nos. the pitch of any given note in the third keyboard, auto

matically raising and lowering it to selective heights

35

and depths at a selected speed. To this end, there is a control knob 56 for a rheostat which sets the repetition rate of the modulator, while another knob 58 controls another rheostat to determine the extent of deviation

658579/651055 and 658580/659056, and also as Gen

eral Instrument Corporation Part Nos. 76194 and 76195. The 12 outputs at 82 are connected to a first

priority latching network 84.

A similar 12 note output appears at 86, the latter being connected to a divide by 2 divider circuit 88 of pitch. A push button 60 permits the modulator to be 40 which divides all of the notes by 2, and divides the one turned on and off. top note a second time by two, thus providing l3 out~ Attack time is controlled by a knob 62 permitting the puts at 90 connected to a second priority latching net player to obtain at his will a fast attack, a slow attack, work 92. or anything in between, thus permitting the crisp play Frequency variable effects are provided at 94, in ing of brass or percussion instruments, or the breathi 45 cluding the modulator previously discussed, slide, delta ness of a woodwind. As a correlary to the attack time, pitch, wah-wah, and also vibrato. Such effects are con sustain time is controlled by a knob 64 which allows the nected at 96 to the master oscillator 78 to modulate the performer to add various lengths of sustain to any master oscillator. A feedback circuit is provided at 98

sound on the third keyboard, including the percussion from the priority latching network 84 for controlling 50 presets of the stop tablets 48. the delta pitch effect, as will be discussed hereinafter. Second touch is provided on the third keyboard. If any one of the keys of the third keyboard 38 is de A high bus rod 100 and a low bus rod 102 are pro pressed its normal extent, the tone plays in normal fash vided as part of the third keyboard 38. Twelve whisker ion. A bail switch is provided beneath the third key wire contacts 104 corresponding to the top 12 notes D board so that a key may be pressed down beyond its 55 through C are individually engageable with the high bus normal depth to produce a special effect. Two special rod 100 and are connected to 12 inputs of the priority effects are provided, namely a special turning on and latching network 84. Similarly, there are 13 whisker off of a modulator, this effect being brought into play wire contacts 106 engageable individually with the low by a push button 64 to provide operation of the modu bus rod 102 corresponding to the thirteen lowest notes lator only when the key is pressed below its normal stop C through C. The whisker wire contacts 106 are indi depth. Alternatively, a push button 66 allows a slide or

vidually connected to the priority latching network 92,

glissando effect, namely a detuning ?at followed by the

and the corresponding note contacts are connected in

note coming up to its normal frequency as the key is de

pressed beyond its normal stop depth. A push button 68 is provided to turn the attack time on, while a push button 70 allows the sustain time control to be turned on.

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parallel as indicated by the wires 108. The priority latching networks are similar to the pedal latching networks which have for some years used in the Wurlitzer model 4300D organs. Somewhat similar networks are shown in Robert D. Barry Pat. No.

3,808,344 5

6

3,422,208 and Harold O. Schwartz et al. Pat. No.

3,480,7l9. Each priority latching network is provided with high note preference, and the higher octave prior

a keyer to the ?lters 136. It should again be noted that the E divider chains do not necessarily produce a fre quency corresponding to the frequency of any E note,

ity latching network has preference over the lower oc tave. If any one note key is depressed for a particular

but bear the relation of a musical note E to the notes of the G divider chains 130 and 158 and to a musical

priority latching network, say for example for the high

C note as in the divider chains 146 and 1611.

priority latching network 841, that note will play and will continue to play even though the key is released, until

190 and 192. The output 190 is connected to the con

The steering circuit 112 is provided with two outputs trol points A and A’, while the output 192 is connected

another key is depressed which cancels the ?rst note latched in, the second played note then continuing until another note is played, etc. As indicated, should the musician depress two keys at the same time, the highest key note will have preference.

to the control points B and B’. The outputs 190 and

192 are alternatively “go” and “no-go” outputs. Either will be go and the other no-go, depending on whether the musician plays a note corresponding to the high section of the keyboard and hence contacts a whisker 104 against the high bus 100, or vice versa. The output

The high bus rod 100 is connected at 110 to a steer

ing circuit 1 12, and the output at 1110 continues at 114 192 is always exactly the opposite of the output 190, to a spike ampli?er 116. The production of a spike whereby a go signal is applied at control points A and upon closing of a key switch is well known in the art, A’ with a no-go signal applied at points B and B’, or see for example Harold O. Schwartz et al., Pat. No. vice versa. Thus, the steering circuit in cooperation 3,340,344. The spike so produced may be used to key rhythm effects, etc. Similarly, the low bus rod 102 is 20 with which of the buses is contacted determines whether the G, C, and E divider chains corresponding connected at 118 to the steering circuit 112, and also

to the spike ampli?er 116. The output of the priority latching network 84 at 120 is connected to a junction 122 leading through a resis

to the top octave or corresponding to the lower octave

will play. Reference now should be made to FIG. 4 with a fur

tor 124 to a control point A. The control point A is 25 ther understanding of the effects produced by the con trols 42. As noted heretofore in connection with FlG. connected through a resistor 126 to a junction 128. 2 the master oscillator 76 is controlled at 96 from fre From the junction 128 connection is made to a “G” di quency variable effects 94. Speci?cally, and as implied vider chain 130, leading to a keyer 132. The keyer is in connection with FIG. 3 and the controls 42, the fre provided with an output at 1341 leading to ?lters 136. quency variable effects comprise a slide effect applied The output of the ?lters 136 is applied to an ampli?er to the master oscillator 78 on the line 194, and modula 138 which feeds a loudspeaker or loudspeaker system tor effects applied to the master oscillator on a line 140. 196. Considering ?rst the slide line 194, it will be seen The junction point 128 also is connected to a fre

quency multiplier circuit 142 which multiplies the fre

that this leads to a ?xed contact 198 of a switch 200

quency by two, and this is-in turn connected to a divide 35 having a movable switch contact 202 closed by the sec~ ond touch bale 2114. The movable contact 202 leads to by three circuit 144 leading to a “C” divider chain 146, a ?xed contact of a normally open slide switch 206. the output of which is connected to a keyer 1418 leading When the slide push button 66 is depressed, the switch to the ?lters 136. The outputs of the divider chains 130 206 is closed, and the side of the switch opposite to the and 146 are in the relation of musical note G to musical note C. It will be understood that the input to the G di 40 switch contact 2112 is grounded. Hence, whenever a key

is not necessarily G, the important thing being that the

of the third keyboard 38 is depressed below its normal down position, it will depress the second touch bale to

outputs of the dividers 130 and 1416 have the relation of G and C.

- close the switch 2112, and hence apply ground to the line 1941 to detune the oscillator 78 slow or flat from its

vider chain 130 can be anything from B through C, and

Returning to the priority latching network 841, and speci?cally the output 120 thereof, the junction 122 is

45

that it will produce a half tone ?at detuning in the audio

frequency from the divider 611. When the key that has

further connected to a resistor 1511 leading to a control point B which in turn is connected to a resistor 152 to

a junction point 154. The junction point 154 is con nected to a divide by two circuit 156 to a G divider

normal oscillating frequency. The detuning is suf?cient

been depressed beyond its normal bottom position is 50

released, the second touch bale 204 will rise, and the switch 202 will open, whereby ground is removed from

the line 1941, and the oscillator 78 comes back up to its normal frequency at a controlled rate. 160, and then on to the ?lters 136. The modulator line 196 has several connections to it, The junction point 154 is also connected to a divide by three circuit 162 to a C divider chain 164 and out 55 the ?rst of which is a line 2118 from the delta pitch switch 210, a normally open switch closed by the push through a keyer 166 to the ?lters 136.

chain 158, the output of which is connected to a keyer

button '72, and having applied to the opposite side Turning now to the priority latching network 92, the thereof a signal through a delta pitch line from a delta output thereof at 168 is connected to a junction point pitch circuit 214 to be described hereinafter in some 170. The junction point 170 is connected through a re sistor 172 to a control point A’, with connection from 60 detail. The modulator line 196 also has connected to it a line the control point being through a resistor 1741 to an “E” 216 leading to the second ?xed contact 218 of the sec divider chain 176, the output of which is connected ond touch bale switch 206. A second movable switch contact 2211 is ganged at 222 with the movable switch to a divide by two circuit 1811 which is connected 65 contact 202, and the movable contact 220 is connected to the movable contact 224 of a normally open modula through a resistor 182 to a control point B’. The con tor second touch switch 226. The modulator second trol point B’ is connected through a resistor 1841 to an through a keyer 178 to the ?lters 136.

.

Connection is made from the junction point 1711 also

other E divider chain 186 which is connected through

touch switch 226 is closed by the push button 64, and

3,808,344 7

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when it is closed, and the second touch bale 204 is low

nection is made to the ?xed contact 270, and hence to the wah-wah filter 278, whereby a wah-wah effect is

ered by pressing of a key below its normal down posi~ tion, a signal is applied by way of the line 216 to the line

196, the signal being a varying signal.

impressed on the reed, brass, and string sounds, the output being through the ampli?er 284 to the line 286

The switch 226 is connected by means of a line 228 to a fixed contact 230 of a modulator switch 232. The

and on out to the final ampli?er 138.

switch 232 includes a movable arm or contact 234 nor

is appIied-Qoabanjo ?lter 290, the output of which is

mally engaging an open ?xed contact 236, the switch arm 234 being moved into engagement with the switch contact 230 upon depression of the push button 60. When the push button 60 is depressed, the modulator effects are connected to the line 196 irrespective of the

connected to the bus 274. Similarly, the bus 250 is ap plied to the input of a harpsichord ?lter 292, and to the

second touch bale position.

referred to comprise part of the ?lter group controlled

The ?xed contact 230 of the switch 232 is connected by a line 238 to a sliding tab 240 on the potentiometer 242. The tab is controlled by the deviation knob 58.

group comprise vibes 296, xylophone 298, glock (or

The outputof the 8 foot ampli?er 248 on the bus 250

input of an electropiano ?lter 294, the outputs being connected to the bus 274.

The banjo, harpsichord, and electropiano ?lters just by the stop tablets 48. The remaining stop tablets in this

The bottom end of the potentiometer 242 is grounded,

glockenspiel) 300, and chimes 302. These are not con nected to ?lters that are strictly complex tone ?lters,

while the top end is connected to a modulator 244. The

but are connected to the footage ?lters which are not

speci?cally shown. The vibes stop tablet 296 comprises repetition rate of the modulator is controlled by a po tentiometer 246, the sliding tab of which is controlled 20 a control for a switching circuit which turns on the 8 foot ?lter and also momentarily a 2 foot ?lter to pro by the knob 56. duce, respectively, a fundamental and a strike tone, as Turning from the special effects controls at the right indicated at 304. Similarly, as indicated at 306, the xy side of the third keyboard to the stop tablet controls at lophone stop tablet 298 controls the turning on of an the left side thereof, attention should be directed to FIG. 5. Footage filters for producing sine waves of the 25 8 foot fundamental and a 2% foot strike tone. In like fashion, the glock stop tablet 300 controls a 4 foot fun footage as illustrated in FIG. 3 is a simple and conven damental and a 1% strike tone as indicated at 308. Fi tional matter. The oscillations throughout other than nally, the chimes stop tablet 302 turns on the 6-2/5 from the master oscillator are square waves, and these foot, the 4 foot and the 2% foot ?lter, plus a short time are filtered by active ?lters to produce sine waves. Hence, the footage sine wave details are not shown. 30 turn on of a 2 foot ?lter as a strike tone, as indicated at 310. The outputs of the ?lter sets at 304, 306, 308 However, the connections for the complex ?lters are and 310 are connected direct to the ampli?er 138, as shown in FIG. 5. Starting at the lower left corner, there are all of the footage ?lters comprising part of the ?l is an eight foot ampli?er 248 receiving the output of ters 136. the C divider chain keyer 148 and supplying a bus 250. There is also a l6 foot ampli?er 252 receiving the out 35 Keying voltage switching for the various percussive

put of the lower C divider chain keyer 166, and supply

stops is shown in FIG. 6. The switching is typical, and

ing a bus 254. The bus 254 is connected to a reed ?lter

256 on the input side thereof, and also to the input of a brass ?lter 258. The outputs of both of these ?lters

certain distinctions as to which of the speci?c stop tab lets 48 is operated will be discussed. Starting at the lower left-hand corner of FIG. 6, a spike is supplied

to the input of a string ?lter 262, and the output of the string ?lter likewise is connected to the bus 260.

312 which, when turned on, supplies a controlled posi tive spike out on line 314. The Schmitt trigger circuit

The bus 260 is connected to the movable contact 264

312 normally is biassed so as to be inoperative. How»

are connected to a bus 260. The bus 250 is connected 40 from the spike ampli?er 116 to a Schmitt trigger circuit

ever, the Schmitt trigger circuit is controlled as to oper of a single pole, double throw switch 266 having two 45 ation through a capacitor 316 to a plurality of switches ?xed contacts 268 and 270. The movable switch 318, all of which are on-off switches, and are nonnally contact is controlled by the wah-wah push button 74, open. One of these switches is shown as being typical, and in the normal, rest or idle position, the movable and for example, may be associated with the banjo stop contact 264 engages the fixed contact 268. The ?xed tablet. When the banjo stop tablet is operated, the contact 268 is connected to a line 272 leading to a bus 50 switch 318 is closed to complete a circuit to ground 274. from the Schmitt trigger circuit 312 through the capac The ?xed contact 270 is connected by means of a line itor 316 so that the Schmitt trigger will be operated to 276 to a wah-wah ?lter 278. The wah-wah ?lter is con produce the spike on the output line 314. trolled by a wah-wah keyer comprising a Schmitt trig The line 314 is connected to a junction point 320. ger circuit 280 which receives a signal on the line 282

from the spike ampli?er 116, whereby to provide a

From the junction point a line 322 leads to a ?xed

pulse of controlled width to the wah-wah ?lter each

contact 324 of a single pole double throw switch having a movable contact 326. The switch 326 again is dupli cated, and the one shown is typical of switches asso ciated with all of the percussive stop tablets 48. The movable switch contact is connected, depending on the switch which is under consideration, to keying diodes 328 associated with the 1% foot stop for producing the glockenspiel tone. Alternatively, and depending on the

time a spike is supplied from the spike ampli?er 116, i.e., each time a key is depressed. The output of the wah-wah ?lter 278 is connected to an ampli?er stage 284 of a complex ampli?er, and to an output line 286 leading to the amplifier 138. As will be seen, with the movable switch contact 264 in the idle position shown,

the signal from the reeds, brass, and strings simply passes on the lines 272 and 274 to the ampli?er 288, forming a part of the complex ampli?er, and out on the line 286 to the ?nal ampli?er 138. On the other hand, when the wah-wah push button 74 is depressed, con

switch selected as typical, connection will be made to ' keying diodes 330 connected to the 2% foot keyer for

producing xylophone effect, or to keying diodes 332 connected to the two foot stop for vibes or chimes. The

3,808,344

10

cuit 368 having an output at 370 to the cathode of a diode 372. The divide by 2 circuit 368 also is con nected in cascade with a second divide by 2 circuit 374 having an output at 376 connected to the cathode of a

keying diodes 328 are labeled as KG, since the keying is to the high G keyer 132. The keying diodes 330 are labeled as KX, and are connected both to the high G keyer 132 and to the low G keyer 160. The keying di

diode 378. The anode of the diode 372 is connected to a junc 148 and the low C keyer 146. With the movable switch tion point 380, and this junction point is connected contact 326 in the raised position shown, the short through a resistor 382 to a biassing and keying voltage spike on the line 314 is not applied to any of the keying source 384 which normally is at a potential which is diodes 328, 330 or 332. The junction point 320 also is connected by a line . . 0 negative relative to the cathodes of the diodes 372 and 378 to bias the diodes off. The keying voltage also is 334 to one ?xed contact 336 of a sustain switch 338 connected through a resistor 386 to a junction point having a movable contact 340 controlled by the sustain 388 which is connected to the anode of the diode 378 on push button 70. In the raised position shown the sus whereby both diodes are biassed off. tain is off. The movable switch contact is connected by

odes 332 are labeled KV, comprising the high C keyer

_, The junction point 380 also is connected through a resistor 390 to an output circuit 392 leading to ?lters

a line 342 to a ?xed contact 344 of a banjo switch 346

having a movable contact 348 controlled by the banjo stop tablet comprising one of the stop tablets 48. The movable switch contact 348 in the raised position shown engages a ?xed contact 350 which is connected

to a junction point 352. The junction point is con nected to an input line 354 receiving a pulse 356 having a sharp leading edge and a decaying trailing edge. The width of the pulse 356 and the character of the trailing edge are controllable, and the source of this pulse will be set forth at a later point herein.

as previously noted. Similarly, the junction point 388 is connected by means of a resistor 394 to an output line

396 also leading to certain of the ?lters previously men 20

tioned. When a keying ~voltage is applied at point 384, both diodes 372 and 378 are biassed on so as to con

25

The junction point 352 also is connected by a line 356 to the second ?xed switch contact 358 of the sus tain switch 338. The movable switch contact 348 is connected to a

duct signals from their respective divide by two circuits 368 and 374 to their respective filter output paths 392 and 396. Which of the two will sound, the oscillations being an octave apart, and hence corresponding, for example, to an 8 foot and a 16 foot pitch, depends on which ?lters are turned on by the respective stop tab lets. The resistance of the resistors 382 and 386 is high enough compared with the resistance of resistors 390 and 394 that no substantial output from the divider 368 will appear on the output line 396, and vice versa.

line 360 leading out to keying diodes 362, comprising part of the low G keyer 160 and of the low E keyer 188.

The pulse appearing on line 98 at the inception of a

The line 360 also is connected to the second ?xed

note is used for attack and sustain control in connec tion with the circuit of FIG. 8. The signal on the line 98 326. 35 is applied to an ampli?er 398 which provides the gate With the various switches of FIG. 6 in the position signal shown below it as 400. This gate signal is con shown, there is no short spike from the Schmitt trigger nected to a junction point 402 and across a capacitor keyer 312, and there is no place for such a spike to go _ 404 to a junction point 406. The transition signal if there were one. On the other hand, assuming that a

contact 364 engageable by the movable switch contact

passed by the capacitor 404 to the junction point 406 is applied to another junction point 408, and from this

pulse 356 is generated, it is applied to the keying diodes at 362.

to the top of a variable resistor 410 controlled by the attack knob 62. Speci?cally, the knob 62 controls the position of the slider 412 on the resistor 410. The slider

If the banjo stop 48 is selected as the typical stop to be operated, then a pulse is applied on the line 314, due to closure of the switch 318. There is not a typical

switch including the arm 326 corresponding to the banjo stop, so the pulse does not go anywhere in this

412 is connected to a ?xed contact 414 of an attack-on 45

switch 416 controlled by the push button 68. When the attack is off, the ?xed contact 414 is open. However,

direction. However, it does go on the line 334 to the when the attack is on, the fixed contact 414 is engaged switch 338, assuming the sustain is left off, and goes to by the movable contact arm 418 of the attack switch the switch 346 which is now closed on the lower 416 whereby to convey the attack pulse signal to a contact 344 and hence to the keying diodes 362, and junction point 420. This junction point is connected to hence to produce a short burst of banjo-like sound. an amplifier 422 to supply the keying voltage switching On the other hand, if it be assumed that the typical pulse 356 previously referred to in connection with stop operated is not the banjo stop, but is one of the FIG. 6. The value of the resistor 410 combined with the other stops associated with the stop tablets 48, and spe ci?cally one of the vibes, Xylophone, glock, or chimes, 55 size of a capacitor 424 shunting the junction point 420 to ground determines the shape of the leading edge of then the short spike appearing on the line 314 will turn the keying voltage pulse 356. on the appropriate diodes 330, 328, 332 for a brief The capacitor 404 is parallelled by a pluck attack time. At the same time, the longer pulse 356 will be ap electric switch 426 connected to the junction points plied to the keying diodes 362 to produce the longer or fundamental tone. Other combinations upon operation 60 402 and 406. The pluck attack electric switch is nor mally closed, but is opened by a potential appearing on of the various switches will be apparent to those skilled a line 428 forming the output line of a DC ampli?er in the art. 430, the input of which is normally open, but which is Reference has been made heretofore to voltages ap connected to ground by closing of a switch 432. There plied to keying diodes, and a typical diode keying cir

cuit is shown in FIG. 7. A frequency input is indicated 65 are six such switches, operable more or less in parallel, and each is closed by a respective stop tablet of the stop at 366, and this could be the frequency input of any of tablets 48 as indicated in FIG. 8, namely harpsichord, the divider chains heretofore identi?ed in connection electropiano, xylophone, vibes, glock, or chimes. When with FIG. 2. The frequency input is to a divide by 2 cir

3,808,344 11

12

the switch 426 is on, and this switch, by way of simple

A long sustain electric switch 484 is connected from

example, can be a transistor which is biassed to con

the junction point 472 to the junction point 460 adja

duct or not to conduct, the DC level of the output of

cent the sustain on switch 450. The switch 484 is bi assed for conduction or non-conduction by a normally

the ampli?er 398 will be applied to the junction point 406, thus providing a different type of potential thereto

open grounded switch 486.

than is possible through the capacitor 404.

As will be apparent, if the sustain on switch 450 is in

The junction point 408 likewise is connected to a preset attack electric switch 434, the other side of

the off position as shown, and if the long sustain elec tric switch 484 is open, the sustain time is determined by the resistor 458. If the switch 484 is closed, then the

which is connected to the second ?xed contact 436 of

the attack-on switch 416. The switch 434 normally is biassed for conduction by means of a normally closed

resistor 458 is parallelled by the series combination of resistors 464 and 470, thereby providing a somewhat lower resistance, and shortening the sustain time. With the long sustain electric switch 484 closed, if the me‘ dium long sustain electric switch 482 conducts, it shorts the resistor 470, whereby the resistor 464 is in parallel with the resistor 458, producing a somewhat lower resistance, and a shorter sustain time. Similary,

grounded switch 438. Thus, normally the signal appear ing at junctions 406 and 408 is applied without change to the junction point 420 at the top of the attack and sustain capacitor 424 and forming the input to the am pli?er 422 to provide a preset rapid attack. When a typ ical switch operator is used to open the switch 438, the

speci?c illustrative example being for the string stop

if the medium sustain electric switch 474 is in the on condition with the switch 482 open, then the resistor 20 470 is parallel with the resistor 458, presenting a some ‘ with a string sound which has a non-percussive type of . what lower resistance, and providing a medium sustain. . inception. On the other hand, if the sustain on push button 70 is In addition to the discharge path provided by the. depressed, the switch 450 is reversed in position, to re input to the resistor 422, the junction point 420 at the move all of the previously mentioned resistors and elec

tablet, the attack signal is not applied to the ampli?er 422, and it will be appreciated that this is in keeping

top of the attack and sustain capacitor 424 is con 25 tric switches from the circuit, whereby sustain of the nected to a discharge or sustain path 440. The path 440 ' pulse 356 is determined by the variable resistor 444, as

adjusted by the sustain knob 64.

leads to a junction 442 which is connected to a manual

sustain circuit including a variable resistor 444 having a tap 446 thereon, the position of which is controlled

The wah-wah ?lter 278 has been noted heretofore in connection with FIG. 5, and details on this ?lter will be by the sustain knob 64. The tap is connected to a ?xed 30 seen in FIG. 9. The input line 276 is connected from contact 448 of the sustain on switch 450, the movable the brass ?lter through the wah-wah switch 266 re~ arm 452 of which normally does not engage the ?xed ferred to in FIG. 5 to the input of the wah-wah ?lter contact 448, but which is brought into engagement 278 through a capacitor 488 shunted to ground by a re therewith upon depression of the sustain on push but sistor 490 in accordance with conventional practice. ton 70. The movable contact 452 is connected by a line 35 The input is connected to the base of a transistor 492, 454 back to the junction point 402, so that with the the emitter of which is grounded. The collector is con manual sustain on the capacitor 424 is in part dis nected through a resistor 494 to a positive voltage sup charged by the potential appearing at 402 when the ply line 496. Voltage divider resistors 498 and 500 pro gate signal 400 reverts to its normal state. vide proper bias for the base. The sustain line 440 also leads to a junction point 456 40 Connection is made from the collector of the transis which is connected through a resistor 458 to a junction tor 492 through a capacitor 502 to a junction point 504 460 leading to the second ?xed contact 462 of the sus~ on a voltage divider comprising a resistor 506 con tain on switch 452. Thus, when the manually controlla nected to the positive supply line 496 and a grounded ble sustain is not switched on, a preset sustain is pro resistor 508. Connection is made direct from the junc

vided by the resistor 458, quali?ed in that it may be parallelled by other resistors as hereinafter set forth.

45

The junction point 456 on the sustain line is con nected to another junction point 462 which leads

junction point 514 is connected through another light

through a resistor 464 to a junction point 466. The

dependent resistor 516 to the base of an N-P-N transis tor 518, the collector of which is connected to the base of another transistor 520 in a Darlington ampli?er con~

junction point 466 is connected direct to a junction point 468, and this is connected through a resistor 470

?guration, the output being taken from the emitter of

to a junction point 472. A normally open medium sus tain electric switch 474 is connected from the junction

point 462 to the junction point 466, and is biassed by means of a line 476 to conduct, and hence to short out

the resistor 464, whenever a grounded switch 478 is

tion point 504 to another junction point 510 which is connected to a light dependent resistor 512, the other end of which is connected to a junction point 514. The

55

the transistor 520 through a resistor 522 to an output at 524. The emitter is grounded through a resistor 526.

The junction point 514 between the two light depen~

closed. There are three such switches in parallel, re

dent resistors is connected by a capacitor 528 to the

spectively being closed whenever the harpsichord, xy lophone, or glock stop tablet is operated. In addition,

emitter of the transistor 520, being therefore nearly at DC ground potential. The base of the transistor 518 is shunted to ground by a predetermined value capacitor 530, and also by a capacitor 532, the value of which is selected from a predetermined group of values during production in order to compensate for other variables in the system, and to produce the desired results. A connection is made from the voltage supply line

there is a two pole normally open switch 480 controlled

by the electropiano stop tablet, and whenever this is closed ground also is applied to the line 476 to close the switch 474. A medium long sustain electric switch 482 is con nected between the junction points 468 and 472 to short out the resistor 470 when the switch 482 is closed

496 through a resistor 534 to a line 536 leading to one

by the second pole of the electropiano switch 480.

side of a lamp bulb 538, the other side of which is

3,808,344 13

14

grounded at 540. Although this is shown convention ally as a tungsten lamp bulb 538, it will be appreciated that somewhat different types of results could be ob tained with different types of light emitting sources, such as a light emitting diode. Finally, an input pulse is applied to an input line 542, 4% by a resistor 544, and

output side will rise to its normal quiescent level, pro ducing a short pulse as illustrated at 574 in FIG. 10 which is used to detune the master oscillator momen

also direct by means of a line 54.6 to the line 536 lead

tarily to a somewhat lower frequency, thus producing a drop in pitch of each audio tone of approximately a half semi-tone at the inception of the playing of the note, followed by rapid return to the proper note fre'

ing to the lamp bulb 538. The shape of the pulse ap

quency.

plied on the line 542 from the Schmitt trigger 280 is shown at 548 at the upper left of FIG. 9. Normally, the lamp bulb 538 burns at a predeter mined level of illumination as determined by the volt age source supplied to the line 496 and by the value of the resistor 534, as well as inherent characteristics of

Attention now should be directed to FIG. 11 for a

more detailed showing of the master oscillator 78. The oscillator includes an NPN transistor 576 the emitter of which is grounded. The collector is connected to a

junction point 578 and through a resistor 580 to a posi tive voltage supply line 590. The collector also is con

the lamp bulb. The light from the lamp bulb 538 im pinges on the two light dependent resistors 512 and

start of a brass tone, a greater voltage is momentarily

nected back to the base through a resistor 592, and is connected through a capacitor 594 to the top of an in ductance coil 596, the bottom of which is grounded. The top of the inductance coil also is connected by a capacitor 598 to the base of the transistor 576. The slide line 194 is connected through a resistor 600 to the common input line 96 which leads to the base of the transistor 576. Similarly, the modulating or vibrato line 196 is connected through a resistor 602 to the

applied to the line 536, raising the potential thereon

common line 96.

516. As will be recognized, if no light at all were on

these resistors, they would be of a very high value. Since a certain level of light is on the resistors, they have a lower value, and conduct the input signal from

the amplifying stage comprising the transistor 492. When a pulse from the Schmitt trigger is applied at the from a nominal 7.5 volts by an additional 5.3 volts, 25

It thus will be seen that there is an inductance

thereby causing the lamp bulb 538 to burn at a higher

capacitance tuned oscillator, the constants of which are

level of illumination. This momentarily drops the value of the resistors 512 and 516, whereby to increase the level of the signal applied to the Darlington transistors

The oscillations produced are of a sine wave, and volt

and 516, thus producing a momentary frequency de

and this is connected to a parallel combination of a re

chosen to produce an oscillating frequency of 1.5 MHz.

ages applied to the base through the line 96 will pro 518 and 520. It will be recognized that the resistors 512 30 duce detuning thereof to produce a slide, vibrato, etc. and 516 act with the capacitors 528 and 530, 532 as The output of the oscillator 78 is taken from the junc RC filter, the frequency characteristics of which are changed upon changing of the value of the resistors 512 tion point 578 connected to the transistor collector, tuning as well as change in volume level whereby to 35 sistor 604 and a capacitor 605 to sharpen the leading edge of the wave. The resistor-capacitor combination produce the characteristic WAH sound at the start of is connected to the base of an NPN transistor 606, a brass tone, as is used in playing a trumpet or the like comprising a buffer stage, and having the emitter con with a wah-wah sound. The delta pitch circuit 214 has also been referred to nected to ground through a resistor 608. The collector in connection‘with FIG. 4, and details on this circuit 40 of the transistor 606 is connected to a positive voltage will be seen in FIG. 10. The pulse previously referred supply line 610 through a resistor 612, and the collec to as appearing on the line 98 upon the inception of I tor is also connected through a capacitor 614 to the base of an NPN transistor 616 forming another buffer playing of a tone is applied at 550 through a resistor 552 to the base of a transistor 554., The transistor is of stage. The emitter of the transistor 616 is grounded the N-P-N type, and the emitter thereof is grounded. 45 through a resistor 618, and the output is taken from the The collector is connected through a resistor 556 to a emitter at 620, leading to the LS1 divider 80. The col lector is connected to a positive voltage supply source positive voltage supply line 558, and is also connected 622, and the base is also connected to this positive volt through a resistor network 560 and 562 to the base of age supply source through a resistor 624. an amplifying transistor 564, this transistor also being Circuit details and operation of the steering circuit of the N-P-N type and having the emitter grounded. The collector is connected through a resistor 566 to the

112 will be seen with reference to FIG. 12. The line 110

positive voltage supply line 558, and is also connected

from the high end of the bus 100 is connected through

direct to a capacitor 568 of rather high value. For ex ample, the capacitor 568 may be on the order of ten

a resistor 626 to the base of an NlPN transistor 628,

having the collector thereof connected through a resis tor 630 to a positive voltage supply at 632. The emitter

MF D. The opposite side of the capacitor 568 is shunted to ground by a diode 570, poled as shown with the

is connected to a line 634 of which more will be said

later. The collector further is connected through a re anode connected to the capacitor and the cathode con sistor 636 to the base of another NPN transistor 638, nected to ground. A resistor 572 is connected to the junction between the capacitor and the diode to pro 60 the emitter of which is grounded through a resistor 640. The base also is connected to ground through a resistor vide the delta pitch output on the line 212.

As will be recognized, when the negative going pulse

642, the resistors 636 and 642 being of equal and rather high value, as compared with the resistor 626,

is applied on the line 550, conduction of the transistor 554 will suddenly increase, and that of the transistor

564 will suddenly decrease, thereby rapidly dropping the potential at the collector of the transistor 564. This, in turn, will very rapidly drop the potential on the out put side of the capacitor 568, and the potential on the

65

and particularly the resistor 640. The collector of the transistor 638 is connected through a resistor 644 to the line 118 from the low end of the bus 102. The emit ter of the transistor 638 also is connected to a line 646.

3,808,344 16

15 The two output lines connected to the emitters of the

628, causes transistor 650 to be cut off. This raises the

potential at point 652, and transistors 672 and 674 will

transistors 628 and 638, namely 634 and 646, lead to a ?ip-flop circuit 648 comprising a pair of NPN transis tors 650 and 652. The emitters of both transistors are grounded. The collector of transistor 650 leads to a

A’, whereby signals applying at points A and A’ are

junction point 653, and from thence through a resistor 654 to a positive voltage supply line 656. The junction

played.

conduct, thereby effectively grounding points A and grounded out, and do not pass on to the respective di

vider chains. Accordingly, only the lower octave is

A simpli?ed generally block diagram showing effects

point 653 also is connected through a resistor 658 to the base of the transistor 652. The line 634 is connected to the base of the transistor 650, and this base is connected to ground through a re sistor 660. The collector of transistor 652 is connected to a junction point 662, and from thence through a re~

within the modulator 244 discussed in connection with FIG. 4, is connected by means of an on-off switch 686

sistor 664 to the positive voltage supply line 656. As

to the line 96, and varies the voltage applied to the base

will be understood, the resistors 654 and 664 are of

of the oscillator transistor as discussed in connection with FIG. 11, to cause the frequency of the master os cillator to rise and fall about the nominal oscillator fre‘ quency at a rate such as to produce a cyclic audio fre

equal value. The junction point 662 also is connected

control on the oscillator will be seen in FIG. 13. Thus,

the master oscillator 78 again is shown with the input line 96. A vibrato oscillator 684, generally comprised

through a resistor 666 to the base of transistor 650 and it will be understood that resistors 658 and- 666 are quency variation of about 6 to 7 cycles per second. equal to one another. Resistor 660 also is equal to resis 20 A slide control comprises a potentiometer resistor tor 640. 688 having one end thereof 690 maintained at a posi Junction point 653 is connected through resistors tive voltage with the opposite end 692 maintained at a 668 and 670 to the bases of transistors 672 and 674, re

negative voltage, the center thereof being grounded as indicated at 694. A slider 696 on the potentiometer grounded. The collector of transistor 672 is connected to point A referred to in FIG. 2, while the emitter of 25 may move either up to raise 'the voltage positive as picked off, or down to produce a negative voltage, the transistor 674 is connected to point A’, also referred to slider being connected to a collector line 698 leading in connection with FIG. 2. _ . to the oscillator input line 96, whereby to raise or lower Junction point 662 is connected through a resistor the voltage on the base of the oscillator transistor, thus 676 to the base of an NPN transistor 678, and also

spectively. The emitters of both of these transistors are

through a resistor 680 to the base of an NPN transistor 30 to detune the oscillator either sharp or ?at, as may be desired. 682. The emitters of both transistors 678 and 682 are

grounded. The collector of transistor 678 is connected to point B in FIG. 2, while the collector of transistor

Reference has been made heretofore to delta pitch, and also to the production of pulses upon closing of any key. A keying pulse amplifier, which may be the ampli ?er 116 previously referred to, is provided with two

682 is connected to point B’ in FIG. 2. If a note is played on the high bus 100, then‘there is 35 outputs. A positive output is applied at 700 to a series a positive signal in on the line 1 10, whereupon the tran capacitor 702 leading to a junction 704. The junction sistor 628 conducts. This lowers the potential at the 704 is connected to the anode of a diode 706 leading bottom of the'resistor 630, and hence lowers the bias to a ?xed switch contact 708 engageable by movable potential to the base of the transistor 638, whereupon the latter is cut off. Meanwhile, due to conduction of 40 switch arm 710 connected to the collector line 698. The junction 704 further is connected to the cathode the transistor 628, a positive potential exists on the line of a grounded diode 712. A positive pulse is passed by 634, whereby the conductor 650 conducts. This lowers the capacitor 702 and by the series diode 706 to place the potential at junction point 652 nearly to ground, a positive pulse on the collector line 698, thus momen» thus to cut off transistors 672 and 674, whereupon points A and A’ are ?oating, and whereupon the signal 45 tarily to raise the voltage on the base of the oscillator transistor, and thus to raise the frequency slightly. Any appearing at those points will pass on through the re tendency for a negative pulse to be passed by the ca spective divider chains. pacitor 702 on the backside of the keying pulse is over On the other hand, the ground potential at point 652, coupled with the relatively low potential on line 646 50 come by the diode 712 which shorts to ground in the negative pulse. due to nonconduction of transistor 638 maintains the

transistor 652 in nonconducting condition. Accord

ingly, there is a relatively high potential at point 662, and transistors 678 and 682 will conduct, thereby ef

fectively grounding points B and B’, and grounding out signals appearing at these points on FIG. 2. Thus, only the relatively higher frequency signals will be transmit ted. Conversely, if a note is played on the low bus 102, then a positive potential is applied at 118, and none at line 110. Thus, transistor 638 conducts while transistor 628 is off. Conduction of transistor 638 raises the po tential at the top of resistor 640, and hence on line 646

to render transistor 652 conductive, thereby cutting off transistors 678 and 682, so that signals appearing at points B and B’ will be transmitted. Conversely, the bias applied through resistor 666 to the base of transis tor 650, combined with nonconduction of transistor

In addition, an output from the keying pulse ampli?er 116 is applied to a 180° phase inverter 713 to provide a negative output pulse, and this is applied to a series capacitor 714 which is connected to the junction 716. The junction is connected to the cathode of a series diode 718 leading to a ?xed switch contact 720 which

is engageable by the movable contact arm 710 upon movement thereof away from the ?xed contact 708. By this means a negative pulse can be applied to the col— lector line 698 into the input line 96 to the base of the

oscillator transistor, whereby to detune the oscillator ?at upon closing of any key. A grounded diode 722 has its anode connected to junction 716 to shunt to ground

any positive pulse at this trailing edge of the spike or otherwise. Finally, in FIG. 13, there is shown a wah-wah effect produced on the master oscillator rather than through

3,808,344 17

18

the use of a ?lter at a later stage. A keying pulse ampli fier 724 will produce an ampli?ed pulse whenever a key is depressed, and this may be connected from the

Embellishments and improvements on the circuit of FIG. 14 are shown in FIG. 15. Most of the circuit is sim

keying pulse ampli?er l 16, or otherwise. The ampli?er will produce a positive going pulse 726 upon key clos ing, as shown, and will produce a negative going pulse 728 upon key release. The output including both such pulses is applied to a series capacitor 730, and prefera

avoid prolixity of discussion. Minor changes will be evi

ilar to that of FIG. 14, and similar numerals are used to

dent, such as inclusion of a resistor 788 in the input line 734 leading to the base of the ?rst transistor 738. One

distinction is that a signal is applied from either priority latching network 84 and 92 to the line 734 such that whenever any note is played the potential on line 734 drops from a positive l2 volts to ground. There is also a resistor 790 incorporated in the return line from the sustain resistor 776 to the line 746. In ad dition, rather than a single output transistor, two tran sistors 792 and 794 are arranged in a Darlington circuit well known in the art. The most signi?cant difference is that the bottom of the capacitor 764 is not connected direct to ground, but rather is connected to a junction point 796 which can be grounded through an on-off switch 798. A resis tor 800 shunts the junction 796 to ground, and a capac

bly through an on-off switch 732 to the collector line‘ 698. Thus, when any key is closed, the master oscillator

is brie?y detuned sharp, and when the key is released, the master oscillator is brie?y detuned flat, thus to pro duce a wah-wah effect in the audio output.

A simpli?ed wiring diagram for playing music or noises with controllable attack and sustain is shown in FIG. 14. An input line 734 is provided from a pulse am

pli?er similar to the pulse ampli?er 116, and a negative going pulse is shown beneath it at 736. The line 734 is connected to the base of an NPN transistor 738, the emitter of which is grounded. The collector is con nected through a resistor 740 to a positive voltage sup ply as indicated at 742, and the base likewise is con nected through a resistor 744 to this positive voltage

itor 802 also shunts the junction to ground. Various types of wave shapes can be produced as shown at the bottom of FIG. 15. The wave shape 804

supply. The circuit produces a percussive effect, and

at the bottom left of FIG. 15 is produced with the the output of the transistor 738 is taken from the col 25 “pluck” switch 786 open. The ?rst portion 806 at the curve, the attack portion is determined by the charging lector on a line 746, shunted to ground by a resistor

time of the capacitor 764 and the effective resistance of the resistor 756 (assuming the percuss switch 798 to

748.}The pulse as ampli?ed by the transistor 738 is ap plied over the line 746 to a series capacitor 750 leading to a junction 752 and shunted to ground by a diode 754

having the anode thereof grounded and the cathode

be closed). The central portion 808 of the curve is sub 30

stantially at the supply voltage, and remains as long as connected to the junction 752. The junction 752 is con the key remains on. When the key is released, the sus tain portion 810 of the curve is produced as the capaci nected to a series resistor 756 having a portion thereof tor 764 discharges through the diode 774 and resistors shunted by a tap 758 and a line 759 leading back to the junction 752. The far side of the resistor 756 is con 776, 790, etc. nected to the anode of a diode 760, and the cathode 35 In the event that the pluck switch 786 is open, the ca pacitor 750 will pass a sharp pulse, very quicky produc thereof is connected to a junction 762.

A capacitor 764 shunts the junction 762 to ground,

ing a peak voltage as seen at 812 in the curve 814. The front portion of the curve would be rounded off to some extent if any residual value of resistance were left follower NPN type transistor 766, having the output taken from the emitter as indicated at 768, and having 40 in the resistor 756, and the vertical front of the curve

and the junction is connected to the base of an emitter

the emitter grounded through a resistor 770. The col lector of the transistor 766 is connected to a voltage

as shown is produced when the resistor 756 is entirely shorted out. The sustain portion 816 of the curve is

source 772 which is selected as between plus zero and

provided upon discharge of the capacitor 764.

The third curve 818 is produced with the percuss minus 22 volts. The junction 762 is connected back to the line 746 45 switch 798 open. Again, the attack time is at a mini mum so that the voltage rapidly rises to the peak at by a diode 774 having the anode thereof connected to 820. However, the sustain portion 822 of the curve is the junction 762 and having the cathode thereof con nected to a resistor 776. A slider 778 is connected to somewhat different, having an initial very rapid drop portion 824 as the capacitor 802 discharges through the resistor, and a line 780 connected to the slider acts 50 the resistor 800, followed by a more gradual portion with the slider to short part of the resistor, the two 826 as the capacitor 764 discharges. being connected back to the line 746 by a line 782. The We have now disclosed a novel electronic musical in slider 758 controls the attack, while the slider 778 con strument comprising a synthesizer added to a generally trols the sustain. A wave shape 784 is shown beneath the circuit, and it will be recognized that the rising part 55 conventional electronic organ. The synthesizer com prises an additional keyboard centered above and be of the wave is determined primarily by the value of the hind the usual'keyboard, with controls for the addi resistor 756 and by the capacitor 764 as the capacitor tional keyboard disposed to either side thereof. These 764 is charged, while the negative part is determined by controls provide the musician with unprecedented con discharge of the capacitor 764 through the diode 774, trol over the character and quality of the sound. Attack the sustain resistor 776, and the resistor 748. A switch and decay characteristics are readily varied to suit the 786 bypasses the capacitor 750, and when closed this requirements of the musician. The pitch of notes can be switch holds the wave shape 284 at its peak until such modulated at will, the pitch of a note can be detuned time as the key is opened whereby music or noise is at inception of each tone, and a wah-wah effect can be sounded as long a key is depressed. When the switch ‘786 is open, there is a percussion effect in which both 65 produced at will. The additional keyboard is provided with a second touch for controlling pitch variation, attack and decay are controllable by the player, some augmenting the effects noted above. Novel electronic what similar to that previously discussed in connection circuits are utilized to produce the desired results. with FIG. 8.

3,808,344 19

20

tively connected to said frequency transmission net works, and wherein there are two frequency division

The specific examples of the invention as herein shown and described are for illustrative purposes only, and various changes will be apparent to those skilled in the art and will be understood as forming a part of the present invention insofar as they fall within the spirit

means respectively connected to said network outputs. 9. An electronic musical instrument as set forth in

claim 8 and further including means interconnected with the two parts of the keyboard and with the two fre quency dividing means for respectively rendering one

and scope of the appended claims. The invention claimed is as follows:

1. An electronic musical instrument comprising means for generating electric oscillations correspond ing to musical tones and comprising two substantially parallel channels, a keyboard having at least two dis crete parts, means connecting said oscillation generat ing means and said keyboard for effecting manual con trol of said oscillation generating means, and further means interconnecting said keyboard and said channels for respectively rendering one channel operable and the other inoperable depending upon which part of said keyboard is played on, operation of a key of said key board providing an input to both channels, the means

of said frequency dividing means operative and the other inoperative depending upon which part of the keyboard has a key depressed. 10. An electronic musical instrument as set forth in claim 7 wherein the frequency divider means has at

least two dividers of different dividing ratio to produce at least two note frequencies in musical chordal rela tion. 11. An electronic musical instrument as set forth in claim 8 wherein the two frequency divider means to

gether have a plurality of dividers of different dividing ratio to produce at least three note frequencies in chordal relation.

for respectively rendering one channel operable and the other inoperable including means for enabling one of said channels and disabling the other.

12. An electronic musical instrument as set forth in

claim 7 and further including feedback means from said frequency transmission network to said master os claim 1 wherein each channel includes divide by 2 means to produce octave note frequencies and further 25 cillator to effect variation of the frequency of said mas ter oscillator upon the playing of a note. includes additional frequency changing means to pro 13. An electronic musical instrument as set forth in duce note frequencies in musical chordal relation. claim 12 wherein the means for effecting frequency 3. An electronic musical instrument as set forth in variation produces a one shot detuning. claim 2 wherein the frequency changing means of at 30 14. An electronic musical instrument as set forth in least one channel includes divide by 3 means. claim 12 wherein the frequency varying means pro 4. An electronic musical instrument as set forth in 2. An electronic musical instrument as set forth in

claim 3 wherein at least one channel includes a multi

duces repetitive detuning of the master oscillator.

ply by two means in series with a divide by 3 means.

15. An electronic musical instrument comprising a case having therein means for producing electric oscil

5. An electronic musical instrument as set forth in

claim 2 wherein the two channels together among said 35 lations corresponding to musical tones, keyboard means on said case operably interconnected with said additional frequency changing means include means to oscillation producing means for controlling said elec produce three note frequencies in chordal relation. tric oscillations, said keyboard means having a prede 6. An electronic musical instrument as set forth in termined width across said case, an additional key~ claim 5 wherein the means for producing the three note board on said case lying above and behind said key frequencies in chordal relation produce frequencies in board means, additional electronic oscillation generat the relation of notes C, G and E. ing means in said case operably interconnected with 7. An electronic musical instrument comprising a and controlled by said additional keyboard, and manu master oscillator operating at a frequency above audio ally operable controls on said case to at least one side range, a plurality of parallel frequency divider means 45 of said additional keyboard and operably connected to connected to said master oscillator and including fre‘

said additional generating means for controlling the quency dividing means of different dividing ratio, to character of oscillations from said additional electric produce 12 frequencies which are multiples of the fre oscillation generating means, said additional keyboard quencies of the semi-tones of a musical octave, a key board having a plurality of keys, a frequency transmis 50 being of lesser width than said keyboard means and being substantially centered relative thereto, said addi sion network having at least 12 paths each having an tional keyboard including a plurality of keys each man input and an output, said 12 frequencies respectively ually depressable to a normal ?rst position, and further being connected to said inputs, means connecting each being depressable past said ?rst position to a second of said keys to said network paths, each key on depres

sion rendering its respective path conductive, all other paths being rendered nonconductive, means continuing

55

position, and means activated by movement of a key to

the last operated path in conductive condition until a

said second position and interconnected with said addi tional electronic oscillation generating means to effect

subsequent path is rendered conductive and thereupon rendering all other paths nonconductive, and fre

cillations generated by said additional electronic oscil

a predetermined variation in the characteristics of os

quency dividing means connected to said output to pro 60 lation generating means. 16. An electronic musical instrument comprising a vide note frequencies in octave relation. case having therein means for producing electric oscil 8. An electronic musical instrument as set forth in

claim 7 including two similar frequency transmission networks, the 12 frequencies being connected direct to one of said networks and through divide by 2 circuit means to the other of said'networks whereby the out puts of said networks are in octave relation to one an

other, said keyboard having at least two parts respec

lations corresponding to musical tones, keyboard means on said case operably interconnected with said

oscillation producing means for controlling said elec tric oscillations, said keyboard means having a prede termined width across said case, an additional key board on said case lying above and behind said key

3,808,344 22

21 board means, additional electronic oscillation generat ing means in said case operably interconnected with and controlled by said additional keyboard, and manu

17. An electronic musical instrument as set forth in

claim 16 and further including means for selectively de tuning said master oscillator. 18. An electronic musical instrument as set forth in claim 37 wherein said additional keyboard includes a

ally operable controls on said case to at least one side

of said additional keyboard and operably connected to said additional generating means for controlling the character of oscillations from said additional electric oscillation generating means, said additional keyboard being of lesser width than said keyboard means and being substantially centered relative thereto, said addi tional electronic oscillation generating means compris ing a single master oscillator and a plurality of parallel frequency dividing means of different dividing ratios to produce a plurality of frequencies bearing musical note

plurality of keys each depressable to a first predeter mined position, and each further being depressable be yond said ?rst predetermined position to a second pre determined position, and means activated by a key de pressed to second position and interconnected with said master oscillator to detune said master oscillator.

relation to one another, and a plurality of divide by 2 chains of frequency dividers connected to and con

19. An electronic musical instrument as set forth in claim 17 and further including means interconnected with said keyboard and with said master oscillator to detune said master oscillator momentarily upon de

trolled by said parallel dividing means to produce fre

pression of any key of said additional keyboard. *

quencies having octave relation to one another. 20

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