вход по аккаунту


Патент USA US3093711

код для вставки
June 11, 1963
Filed July 17, 1959
3 Sheets-Sheet 1
1815201314 5’ z [a I]
|'~'\_ i.
9 38¢
If I
Fl q-
25 2b
June 11, 1963
Filed July 17, 1959
3 Sheets-Sheet 2
2435 uémlwaugl
.nm.\-| \m.\
. ||_Ia".I . . _
+n I“:iw‘\1
“10.m.m'u iu
June 11, 1963
3 Sheets-Sheet 3
Filed July 17, 1959
F: q- 5
76-5521 ’
FIG. 6
/76 :
TONE eemuamoe
M P.
a m 79
A 7708M? 7
United States Patent O?lC?
Patented June 11, 1963
tial movement of tone, normally observed in an orchestra
or pipe organ.
The second area where known electronic organs gen
Thomas J. George, 11671 Victory Blvd.,
North Hollywood, Calif.
erally fall short of a pipe organ is that of reverberation.
Traditionally we have come to associate reverberation
with the music of the pipe organ because a pipe organ is
Filed July 17, 1959, Scr. No. 827,898
21 Claims. (Cl. 84—1.24)
usually installed in churches, cathedrals, auditoriums and
other acoustically reverberant chambers. Many electronic
The present invention relates in general to electronic
organs are now being installed in homes, where the rooms
organs, and more particularly to new and improved means 10 are usually not reverberant. Rcverberation and ensemble
for the enhancement of the tones produced by an elec
are greatly needed in electronic organ installations in non
tronic organ.
reverberant rooms. Reverberation is needed because it
The electronic organ has now become a serious musi
actually contributes to the ensemble, because of its tra
cal instrument in its own right. Its rising acceptance has
ditional association with organ music, and because it ac
largely been due to two factors; ?rst, it is capable of pro 15 tually makes it easier to play the organ, since it tends to
ducing pleasing sustained tones somewhat similar to the
?ll the gaps between successive notes being played. Re
tones produced by a pipe organ, and second, it is much
verberation adds a feeling of bigness and grandeur to the
less costly to manufacture than a pipe organ. There are,
tones of the electronic organ, to more nearly approach the
however, at least two areas where present day electronic
tonal elfects of the pipe organ.
organs fail to emulate the desirable musical effects pro 20
It has long been know that an arti?cial reverberative
duced by a pipe organ.
effect could be obtained by the use of the delay obtainable
A ?rst one of the areas in which known electronic
with a magentic wire or tape recorder. For example,
organs are de?cient is the production of musical ensemble
multiple pick up heads are employed to obtain a series of
or chorus, which is the full rich musical effect obtained
delayed echoes derived from a magnetic wire recording.
when many instruments are played together, as in a sym
For the purpose of this disclosure, echo is de?ned as one
phony orchestra or in a large pipe organ, when many
acoustic re?ection of the sound, and reverberation as a
ranks of pipes are played together. The effect arises from
series of acoustic echoes, closely spaced in time, and of
diminishing intensity. In another system a reentrant loop
played together they ‘are generally slightly out of tune
type of electronic circuit has been used for obtaining mul
with one another. The result is that when the same musi_ 30 tiple echoes with a single delay mechanism in which a
cal note is played simultaneously, a slight beating or un
signal is recirculated around a circuit loop. However,
dulation of the combined tone occurs which is very pleas
neither of the above described arrangements is capable of
ing to the ear of a listener. This undulation or rise and
providing an organ ensemble and reverberation device
the fact that when two or more instruments or pipes are
fall of the tone is absent when a single instrument or pipe
is played alone. It is, therefore, more pleasing when a
which enhances the tones of the electronic organ. Fur
thermore, there are a number of costly and complex tape
operated reverberation arrangements now used for radio
and recording purposes, but such arrangements are not
suitable for incorporation in a low cost electronic organ
number of instruments or a number of ranks of organ
pipes are played together. The beating producing a musi
cal ensemble or chorus e?'ect occurs because the phase
differences of the tones produced by two or more instru
for home use.
ments or pipes at any given instant combine vectorially, 40
Accordingly, a principal object of this invention is to
thus causing the composite tone to become louder and
provide a low cost magnetic tape mechanism capable of
softer. It should also be noted that where the two instru
producing arti?cial reverberation in an electronic organ.
ments or pipes are separated in space, and the tones are
Another object of the invention is to provide a device
not coming from a single point source such ‘as the speaker
of an electronic organ, the vector combinations of the
tones will not be the same in both cars at any given in
which imparts ensemble to the tones of an electronic
stant, and as the vector relationship changes, there will be
a pleasing three dimensional or stereophonic feeling ob~
served by the listener, as a certain spatial movement is
seemingly imparted to the tones. As more instruments or
organ pipes are added to the ensemble, the musical effect
becomes richer, and the random pattern of the beats be
comes very complex, enhancing still more the tones being
and improved means for stereophonic reproduction of
A basic goal in electronic organ design, especially in in
struments intended for use in the home. is economy of
construction. Therefore, it is customary in instruments of
this type to provide no more than one separate tone gen
erator or oscillator for each musical note of the organ, and
only one ampli?er and speaker system for the entire or
gan. Thus, in most present day electronic organs the
Still another object of the invention is to provide new
organ tones from an organ having but one tone generat
ing source for each musical note of the instrument.
Yet another object of the invention is to provide means
for obtaining true stereophonic ensemble, and true stereo
phonic reverberation in the tones produced by an elec
tronic organ.
An additional object of the invention is to employ ordi
narily unwanted variations in tape speed of a magnetic
tape recorder in a fashion which contributes to the en
semble elfect provided by an electronic organ.
It is still another object of the invention to provide a
60 magnetic tape operated self teaching device for use in
an electronic organ.
It is a further object of the invention to provide means
for obtaining percussion effects from an electronic organ,
fect are lacking since there can be no beating when a note
not equipped to produce such effects.
is played when only one tone generator is provided and 65
In accordance with one aspect of the present inven
since there can be no spatial or stereophonic effect where
tion, a system is provided for generating arti?cial rever
only one speaker, or sound source, is employed. Even if
beration and ensemble effects in an electronic organ in
two or more speakers are provided, the ensemble effect is
cluding a recording arrangement in which a record head
still not obtained Where only one tone generator is uti
and a plurality of pickup heads are arranged along the
lized because the phase relationship of the tones coming
length of a moving record medium. Signals derived from
from the speakers does not change. Accordingly, elec
a tone generator in the organ are reproduced without
major requirements for producing a musical ensemble ef
tronic organs normally lack the important pitch and spa
recording in one channel and in a second channel are
recorded on the record medium via the record head.
Delayed signals of varying phase relationship are de
ensemble and reverberation system in accordance with
the invention. A tape magazine is indicated at 9 upon
which an endless loop of magnetic recording tape 14 is
rived from the record medium by means of the plurality
of pickup heads and are combined for reproduction.
stored. In operation, the tape moves continuously in the
In one particular arrangement, signals derived from
direction indicated by the arrows, around a pulley 16,
the pickup heads are fed back to the record head to
past the erase head 15, a record head 18, and three pick
establish a reentrant loop within which the signals recir
up heads 19, 20 and 21. A high frequency oscillator 73
culate, with means being provided for controlling the
serves a dual function by supplying erase current to the
amount of attenuation during recirculation so that the
erase head 15, and bias current to the record head 18.
time required for a given signal to die away may be set 10 The use of bias currents in magnetic recording is well
to achieve a desired effect. Each of the several pickup
known in the art, and is described in US. Patent No.
heads is suitably spaced along the record medium to
achieve a desired phase relationship between the signals
which contributes to the overall musical effect.
2,351,004-Camras. The oscillator comprises two elec
tron tubes 4 and 4' connected in a push-pull con?gura
tion. Both of the electron tubes may be enclosed within
Further, a record medium transport system is arranged 15 a single envelope, as for example, a tube type 12AU7.
so that variations in velocity of the transport of the
The plates of the electron tubes are connected to op
record medium produce desirable musical effects. In
posite ends of a primary winding 64 of a transformer 5.
one embodiment of the invention, the delayed signals
Operating potential may be supplied to the center tap
from the pickup heads are reproduced in a separate chan
of the winding 64 from a conventional D.-C. power sup
nel from the channel in which the signals derived direct 20 ply, represented in the drawing by a B plus terminal
ly from the tone generator are reproduced so that a
65, via a switch 83. The grids of the triodes are cou
stereophonic effect is achieved.
Furthermore, switching means may be included in
accordance with another aspect of the invention by means
of which the recording arrangement may be employed 25
as a self teaching device.
In accordance with alternative arrangements of the in
vention, the recording device is adapted to produce
special vibrato and c-eleste effects, along with the afore
pled to opposite terminals of the primary winding via
the capacitors 68 and 69, and returned to ground via
the grid resistors 70 and 72, respectively. The cathodes
of electron tubes 4 and 4' are connected to a common
cathode resistor 71. The winding 64 of the transformer
5 and a ?xed capacitor 67 form a parallel resonant cir
cuit which is tuned to a suitable frequency of oscillation,
as for example, 50 kilocyclcs. A secondary winding 63
mentioned ensemble and reverberation elfects which may 30 of the transformer 5 supplies erase current to the erase
be utilized separately or in combination with two separate
head 15 via a capacitor 62, and bias current to the re
channels for stereophonic reproduction.
In accordance with a still further aspect of the inven
tion, tonal sustaining effects may be achieved by the
cording head 18 via a capacitor 61.
An electron tube 3A which may be one of two triode
sections in a dual section tube, such as type l2AU7,
use of a recording arrangement including record and 35 serves amplify the incoming signal from the organ as
pickup heads arranged along the length of a moving
record medium.
A better understanding of the invention may be had
from a reading of the following detailed description,
follows: The signal appearing at a pair of output termi
nals 74 and 75 associated with an electronic organ gen
erator 82, is transmitted to an organ output ampli?er
76 which drives a speaker 77 to produce an audible
taken in connection with the accompanying drawings, 40 tone. The signal from the terminals 74 and 75 is also
coupled to the grid of the electron tube 3A via a resistor
FIG. 1 is a plan view of the physical arrangement of
57 and a capacitor 56. A cathode resistor 58 returns the
one form of the magnetic tape mechanism and the asso
cathode of the electron tube 3A to ground, and operating
ciated electronic parts in accordance with the invention;
potential is applied to the plate via a load resistor 59
FIG. 2 is a side view of the arrangement of FIG. 1, in ' connected to the B plus supply terminal 65 via a lead
which the electronic components have been omitted for
66. The electron tube 3A ampli?es the organ signal and
the sake of clarity;
applies it through a coupling capacitor 60‘ to the record
FIG. 3 is a bottom view of the arrangement shown in
ing head 18.
FIGS. 1 and 2;
Assuming that a switch 83 is closed, and that the oscil
FIG. 4 is a combined block and schematic circuit dia 50 lator 73 is in operation, erase current passes through the
gram of an electronic organ including associated ensemble
erase head 15, and bias current passes through record
and reverberation circuits in accordance with the inven
head 18. As the recording tape 14 is drawn in the direc
tion indicated by the arrows out of the tape magazine
FIG. 5 is a diagrammatic illustration of an electronic
9, over the pulley 16, past the heads 15, 18, ‘19, 20 and
organ showing one physical arrangement of the related
21, and back to the magazine, the erase head 15 removes
parts in one form of the invention;
any magnetic signal which may be already on the tape.
FIG. 6 is a diagrammatic illustration of an organ
The demagnetized tape then passes the record head 18
showing an alternative arrangement of the related parts;
where the signal from the organ is recorded upon the
FIG. 7 is a diagrammatic illustration of an electronic
tape. The tape then passes the pickup head 19, where
organ in which part of the apparatus shown within the 60 the recorded organ signal on the tape is picked up and
organ in FIGS. 5 and 6 has been installed in a separate
applied via a lead 37 to the grid of an electron tube 2,
tone cabinet;
which may comprise a high gain ampli?er pentode such
FIG. 8 is a diagrammatic illustration of an electronic
as tube type 6AU6. The tape next moves past the pick
organ coupled to two separate tone cabinets;
head 20, and here the signal is picked up again, and
FIG. 9 is a diagrammatic illustration of an electronic
assuming that a switch 33 is open, the signal passes
organ coupled to a tone cabinet of special design;
through the winding of the pickup head 19 to the grid
FIG. 10 is a diagrammatic illustration of a recording
of pentode 2 via a lead 37. As the tape moves past the
head and two pickup heads included for the purpose of
pickup head 21, again the signal is picked up and passed
explaining the production of ensemble effects in accord
ance with this invention; and
70 through the windings of the heads 20 and 19 in series,
to the grid of the electron tube 2. Thus, the organ
FIG. 11 is a diagrammatic illustration of a simpli?ed
signal appears three times in rapid succession at the grid
form of an electronic organ in accordance with the inven
tion in which a single ampli?er and speaker are employed.
of the electron tube 2. The actual time elapsed be
In FIG. 4, there is shown a combined block and sche
tween each signal pickup is dependent upon the relative
matic circuit diagram of an electronic organ including an 75 spacing between the recording head 18 and the pickup
heads 19, 20 and 21, and also upon the velocity of
time of signal die away, i.e. the rate of ‘attenuation. These
movement of the magnetic tape as it moves past the
A cathode resistor 38 is connected between the cathode
of electron tube 2 and ground, and a plate load resistor
39 is connected to the B plus supply terminal 65 via
factors are the spacing of the pickup heads along the path
of the magnetic tape relative to the recording head, and
the gain of the reentrant loop, as controlled by the re
sistor 49.
In order to simulate as nearly as possible natural rever
beration, the strength of the signals from the three suc
cessive pickup heads should not be equally loud, but
should diminish somewhat, so that the signal from the
and a plate coupling capacitor 42 carries the ampli?ed 10 head 20 is less than that from the head 19, and the sig
nal from the head 21 is less than that from the head 20.
signal from the plate of tube 2 to the grid of an electron
For this reason a resistor 36 is connected across the wind
tube 3B, which may comprise the second triode section
ing of the head 21, and a variable resistor 34 is connected
of the tube ‘type 12AU7, which also includes the electron
serially with a capacitor 32 to the junction of the heads
tube 3A as described above. A cathode resistor 44 re
turns the cathode of the tube 33 to ground and operating
19 and 20, so that in effect it is shunting both heads 20
voltage is applied to the plate via a plate ioad resistor
and 21. Since the three pickup heads 19~21 are con
nected in series, the total average voltage appearing at
45 from the B plus supply terminal 65 via the lead 66.
the grid of the electron tube 2 from the three picked up
The electron tube 38 ampli?es the signal and the am
signals will be higher than the signal from pickup head
pli?ed signal passes through a plate coupling capacitor
46. A part of the ampli?ed signal is applied, via a re 20 19 alone. The maximum resistance value of the resistor
the lea-d 66. A screen resistor 40 is also connected to the
B plus terminal 65 via the lead 66. The screen of the
tube 2 is bypassed to ground by means of a capacitor 41
electron tube 3A, and another part of the ampli?ed sig
34 is chosen so that the individual signals from heads 20
or 21 are slightly lower than the signal from head 19.
nal is applied to a potentiometer 80 via a resistor 54.
The capacitor 32 provides bass compensation by present
The potentiometer 80 serves as a gain control for an
ing a lower impedance to the passage of high frequency
signals than to low frequency signals. When the value
of the resistor 34 is reduced it lowers the signal voltage
sistor 47 and a resistor ‘50 in series to the grid of the
ampli?er 78 which drives a speaker 79. Thus, the signal
from the tone generator 82 ?rst is reproduced by the
organ speaker 77 and then by the speaker 79, slightly de
layed in time, and with other characteristics described
total average signal voltage appearing at the grid of pen
itode 2. Thus, variable resistor 34 serves as a very eifective
from heads 20 and 21, and at the same time it lowers the
That portion of the signal from the electron tube 3B 30 means for controlling the reverberation, or signal die away
which reaches the grid of the electron tube 3A is ampli
time, in the reentrant loop, from several seconds down to
?cd again and recorded on the magnetic tape again ac
a small fraction of a second. This feature permits the
organist to make rapid changes in reverberation e?ect
cording to the cycle of events described above. A re
even while playing.
current loop is thus established, and the signal continues
to travel around the loop with decreasing amplitude at
Since the slow die away of percussive instruments, such
each new recording. The amount of this amplitude de
as the piano for example, is similar to the die away of
crease is controlled by the value of the resistance of a
reverberation, an effect of percussive sustain may be
variable resistor 49 which is connected as a shunting arm
achieved by means of the present invention. To enhance
between the junction of the resistors 47 and 50 and
this effect a foot operated sustaining pedal (not shown)
ground. When the resistor 49 is adjusted to have zero
may be employed to control the opening and closing of
resistance, the signal from the electron tube 3B is not
a normally open switch 33. This switch when closed,
passed to the grid of the electron tube 3A, and the signal
operates to ground lead 35, thereby short circuiting the
is not transmitted around the loop. However, the signal
variable resistor 34. This causes the reverberation die
from the tone generator 82 reaching the grid of the elec
away time to be a minimum during the time the switch
tron tube 3A is not impeded and likewise the signal reach
is closed. When the switch is opened the die away time
ing the ampli?er 78 is not impeded. This is due to the
is restored to that determined by the value of the resistor
relatively high resistance values of resistors 47 and 50,
34. Thus the player can by opening and closing the switch
which serve as isolation resistors. Thus, even when the
33 with the sustaining pedal, produce an effect similar to
resistor 49 is set to zero, the direct organ signal is repro
that obtained with the sustaining pedal of a piano.
duced by the speaker 77 and the recorded and delayed 50
In a practical instrument the variable resistor 49 ad
organ signal is reproduced by the speaker 79. The resistor
justment need not normally be accessible to the player and
49 has a maximum critical resistance value at which the
signal appearing at the grid of the electron tube 3A from
the reentrant loop is just equal to the signal applied to
that same point from the bone generator 82.
With an
adjustment of the resistor 49 at the maximum critical
resistance value, the gain in the reentrant loop is exactly
equal to one, and the signal, once introduced to the loop,
continues inde?nitely. To overcome this undesirable con
dition, the reentrant loop should always be operated with
may be adjusted as follows: With the switch 33 open, and
the variable resistor 34 advanced to the point of maxi
mum gain, the variable resistor 49 is adjusted until the
gain of the recntrant loop is slightly less than one. This
is accomplished by advancing the variable resistor 49 until
an organ tone, when brie?y played, sounds continuously
after ‘the key is released. The control is then turned back
slightly until the tone stops. This is the setting for maxi
60 mum useful gain and reverberation.
a gain of less than one so that each succeeding transit of
The output resistor 54 is shunted by a capacitor 55, and
the signal around the reentrant loop produces a lower
a low pass ?lter comprised of ‘the resistors 51 and 52,
voltage at the grid of the electron tube 3A than the last,
and a capacitor 53 to compensate for de?ciencies in the
with the result that ‘the signal gradually dies away.
frequency response characteristics of the recording system.
The rate at which the signal dies away depends upon
The input resistor 57 is shunted by a capacitor 56 to ac
the gain ‘in the reentrant loop, and with low gain the sig
oomplish the same purpose.
nal will die away faster than when the gain is close to
The following table of circuit component values for
one. A capacitor 48, which is connected in parallel with
the arrangement of FIG. 4 is given by way of example
the variable resistor 49, reduces the gain within the re
entrant loop for high frequencies, so that high frequencies 70 on y:
will die away faster than the low frequencies. Because of
Capacitor 32 _______________ __rnicrofarads__
the three successive pickup heads 19, 20 and 21, attenua
Capacitor 41 _____________________ __do____
tion does not start until the signal from the last head,
Capacitor 42 _____________________ -_do____.
namely 21, has been picked up and ampli?ed. Thus it
Capacitor 46 _____________________ __do_..__
will be seen that there are two factors which control the 75 Capacitors 48, 53 _________________ __do____
Capacitors 55, 56, 68, 69 ______ __microfarads__
Capacitor 60 _____________________ __do____
Capacitor 61 _____________________ __do____
Capacitor 62 _____________________ __do____
Capacitor 67 _____________________ _-do____
Resistor 34 ______________________ __ohms__
Resistor 36 ______________________ __do-___
Resistor 38 ______________________ __do____
Resistors 39, 47, 50, 51, 52, 57, 80, 86__-do____ 500,000
Resistors 40, 43, 54 _____________ __megohm__
the distance D, and then later ninety-nine and three
quarters cycles recorded in the distance D.
It will be
seen that the vector sum of the voltages will be con
tinuously changing so long as the tape velocity continues
to change. It should be noted that these are not discrete
changes in phase, but continuous changes, accompanied
by actual vector rotation. This fact is readily observable
by the use of Lissajous ?gures on an oscilloscope. This
is important because in the ensemble effect observed with
the organ or symphony orchestra, and which is produced
herein arti?cially, the continuously changing vector re
Resistors 44, 58 __________________ __ohms__
lationships of the sounds in the listener’s cars is a very
Resistors 45, 49 __________________ __do____ 100,000
pleasing musical effect. In musical language these vector
Resistor 59 ______________________ __do____ 56,000
changes are called beats.
Resistors 70, 72 __________________ __do____ 200,000
At this point the distinction between ‘the ensemble effect
Resistor 71 ______________________ __do___..
1,500 15
caused by phase shifting and the reverberation effect re
Windings 63, 64 _____________ __millihenries__
In the installation of an organ in accordance with the
invention, the speakers 77 and 79 should be spatially
separated. The spacing is not critical, but best results
sulting from time delay in reproduction of the signal
should be fully appreciated. Both effects result primarily
‘from the velocity of the tape on which the signal is re
However, reverberation effects result from the
20 corded.
are obtained if they are located in such a way that the
relatively large time delay between the recording of the
listener is more or less between the speakers. In this
signal at the recording head and its subsequent repro
way the acoustic signal from the speaker 77 will tend to
duction by the pickup heads 19 and 20, which delay ap
be louder in one ear of the listener, and the signal from
proximates the time interval between particular sound
the speaker 79 will tend to be louder in the other ear 25 being heard by a listener, ?rst, directly from the musical
of the listener. The loudness of the reverberant tones
instrument and then later being returned from a re?ecting
coming from speaker 79 is adjusted by the player by
surface in echo fashion; whereas the ensemble effect de
means of the volume control 80 for the musical effect
pends upon no ?xed delay but only upon slight varia
desired. This is not a ?xed control, and may be fre
tions in tape velocity, in the above example about one
quently changed by the player, depending upon what 30 percent, which produce the slight phase variations. The
type of music he is playing. As an example, in playing
delay between recording and pickup, which produces the
church music, this control will usually be adjusted so that
reverberation effect, may be considered for practical pur
the reverberant tones from the speaker 79 are as loud as
the direct tones coming from the speaker 77. For faster
poses as a ?xed time interval. There will be slight varia
tions in this delay time interval due to the slight varia
moving popular music, the player may wish to reduce 35 tions in tape velocity but the mean time between record
the loudness of the reverberant tones, and at the same
ing and pickup remains substantially constant. On the
time shorten the length of reverberation by reducing the
other hand, the phase shifting of the signal for ensemble
resistance of the variable resistor 34. Controls for these
effect involves relatively small time variations compared
two variable resistors may be placed upon the control
to the large ?xed mean delay for producing reverbera
panel of the organ where they are readily accessible to 40 tion elfects; the small time factor here is a variation
the player.
Referring now to FIG. 10, the generation of ensemble
effects in accordance with the invention is explained as
follows: The recording head 18 and the ?rst two pickup
heads 19 and 20 of FIG. 4 are shown. The magnetic
gap of the head 19 is indicated as 19A and the gap of
which is continuous and random about a zero point and
relates to the spacing on the tape between individual
cycles of the signal. Thus, it may be seen that the two
effects even though accomplished by the same means are
essentially completely different in character, one depend
ing upon a large ?xed mean time delay and the other
upon relatively small variations in time which are con
tinuous and random about a ?xed point.
the head 20 is indicated as 20A. The moving magnetic
tape 14 is passing the recording head and the two pickup
heads, in the direction indicated by the arrow. It is
The changing phase relationship just described was
assumed that head 18 is continuously recording upon 50 that which occurred when the frequency was 500 cycles.
the magnetic tape a steady tone of constant frequency.
A similar effect will take place at other frequencies, since
The actual physical spacing between the magnetic gaps
it is not the number of cycles recorded on the tape with
of heads 19 and 20 is indicated as distance D. The
in the distance D which is important, but only the in
windings of heads 19 and 20 are connected serially, and
stantaneous phase relationship of the signals which are
voltages of like polarity which are induced in them will
being simultaneously picked up by the two heads. In
be ‘additive, while voltages of opposite polarity will tend
the system of the present invention, small random changes
to cancel. Assume that the signal frequency being re
in tape velocity are taking place continuously, as will
later be explained more fully. These changes cause small
corded upon the tape is 500 cycles per second, and that
the tape is moving at exactly ?ve inches per second. If
differences in the wavelengths of all the signals as re
distance D is exactly one inch, there will be recorded 60 corded upon the magnetic tape. Any given instantaneous
displacement in tape velocity will cause less phase differ
upon the tape in the distance D exactly one hundred
ence ‘at low frequencies than at high frequencies because
cycles. Each cycle will thus occupy a space of .010
the wavelengths are longer at the low frequencies and
inch, and this is the wavelength of the recorded signal.
a greater displacement is required to produce a given
Under these conditions the vector sum of the voltages
phase difference. This is very desirable, since this is
being induced in the pickup heads 19 and 20 will be ap
exactly what happens in the tones from an organ or an
proximately double the voltage of either head taken
orchestra, where the beats occurring in the low notes are
separately, because the voltages are in phase. Now sup
slower than those occurring in the treble notes. An
pose the tape velocity changes slightly, so that instead
equally important result is that the actual phase differ
of there being exactly one hundred cycles recorded within
the distance D, there are now ninety-nine and one-half 70 ence will be different for each musical note, and this tends
to avoid the monotony which would occur if any ?xed
cycles in that space. The result of this will be that the
repetitive pattern of phase differences or beats should
voltages induced in pickup heads 19 and 20 will be out
occur as would be the case in a conventional tape re
of phase and will tend to cancel one another. Suppose
corder mechanism having repetitive wow and ?utter. A
that the tape velocity continues to change so that there
de?nite pattern of beats is easily detectable and is un
are now ninety-nine and one-quarter cycles recorded in
musical and undesirable. ,Asa further aid in avoiding
any detectable beat pattern, three pickup heads may be
provides the power to drive the tape magazine 9. The
shaft 28 may be supported by an upper bearing 28A
Where it passes ‘through the panel, and by a lower bear
used, as is shown .in'FlG. 4 and FIG. 1.
The principle of producing beats by phase differences
between signals in two pickup heads as described above
in connection with FIG. 10, will operate with any two
pickup heads, such as heads 20 and 21, or heads 19 and
21 in FIG. 4. Thus while beats are generated between
heads 19 and 20 as ,described'above, other beats are
ing (not shown).
In the usual tape recorder structure, it is customary to
construct the capstan surface of steel, and the pressure
roller which presses the tape against the capstan of
rubber or some similar material which has a non-slip sur
face, so that slipping is prevented. This is very important
simultaneously generated between heads 20 and 21, and 10 since the slightest slip will cause irregularity in tape travel.
also between heads 19 and 21. The combined pattern
The pressure of the roller against the capstan is, for the
of these three sources of beats is extremely complex, and
not at all repetitive due to the fact that there is no repeti
same reason made quite heavy. This necessitates some
ment of one actual system in accordance with the in
expense of such a linkage and at the same time to increase
kind of mechanical linkage to disengage the pressure roller
tive pattern of wow and ?utter.
from the capstan when the equipment is not in use, in
FIGS. 1, 2 and 3 show respectively the plan view, the 15 order to prevent the formation of ?at spots in the rubber
side view, and the bottom view of the physical arrange
surface of the pressure roller. In order to eliminate the
vention. In FIG. 1, a metal chassis plate 1 supports all
the tape recording mechanism and associated electronic
the friction between the capstan and the pressure roller,
the present structure employs a capstan with a rubber
circuit components, including the electron tubes 2, 3- and 20 surface, which is in contact at all times with the pressure
4 of FIG. 4. A recti?er tube 6 and power transformer
rollers. This permits the use of much less pressure be
7 form part of the B plus supply circuit, not shown but
tween the capstan and the rollers, and eliminates the possi
indicated in FIG. 4 as a terminal 65. The transformer
bility of ?at spots, since there is no hard surface pressing
5 is disposed between the tubes 4 and 6. In FIG. 1 the
into either rubber surface. This arrangement more than
tape 14 is drawn from the tape magazine 9 by means of 25 doubles the friction area against the tape and reduces the
a capstan 10, with the pressure rollers 11 and 12 press
ing the tape into engagement with the capstan. The tape
moves successively past a tape guide 13, the erase head
possibility of tape slippage. As shown in FIG. 2, the
capstan 10 is of greater diameter than the capstan shaft
24 and may comprise a section of thick walled rubber
15, a pulley 16, a tape guide 17, the record head 18,
tubing pressed onto the shaft 24.
the ?rst pickup head 19, the second pickup head 20, the 30
It should be understood that the present disclosure en
third pickup head 21, a tape guide '22, the capstan 10
deavors, among its other objects, to convert to an ad
and pressure roller 11, and back to the magazine 9. One
vantage, one of the commonest limitations of the usual
important feature of this arrangement is that the tape
tape recorder structures, namely irregularity in the velocity
passes the capstan twice, withpressure rollers 11 and 12
of tape movement. The effects variously known as wow
holding the tape firmly against the capstan. Thus a
and ?utter in tape recorder design, and which are highly
closed loop of tape is formed with the capstan control
undesirable therein, are used to advantage in the system
ling the velocity of the tape moving into as well as out
of the invention to enhance the ensemble ellect. Perhaps
of the closed loop, so that a uniform tape velocity is pro
the commonest source of ?utter is that which is due to the
vided in an inexpensive structure. One of the major
eccentricity of the capstan, and is evidenced as a moder
problems in designing any tape recording device is to 40 ately fast frequency modulation, the frequency depending
obtain a structure which provides constant tape velocity.
upon the revolutions per second of the capstan. In organ
This of course is necessary in order to reduce wow and
?utter to a minimum.
In conventional tape recording equipment, where the
tape is transported from one storage reel to another, and
where each reel maintains a constant tension on the tape,
there is a relatively constant load on the tape and driving
capstan. In contrast, where \a tape storage magazine is
music a frequency modulation of the tones at a frequency
of from six to seven cycles per second is known as vibrato,
and is frequently used to artistic advantage. Therefore,
in accordance with the invention, the ratio of the motor
drive pulley 31 and the capstan pulley 29 is selected so that
the capstan rotation will lie between six and seven revolu
tions per second. With this arrangement, any ?utter due
to the capstan rotation will appear as vibrato and will add
employed, the problem is somewhat different due to the
varying load which a tape magazine presents to the tape 50 to, rather than detract from, the ensemble effect desired.
transporting mechanism. At the present state of the art,
Unless a heavy vibrato is desired, the capstan should not
tape magazines generally present a varying load due to
be made intentionally eccentric.
the sliding of the turns of tape against each other, and
Probably the commonest source of wow is that which
the friction introduced thereby. The motor 8 is arranged
is due to the rotation of the pressure roller which holds
to drive the capstan, as well as the tape magazine 9,
the moving tape'against the capstan. The present inven
and details of this arrangement are shown in FIGS. 2
tion endeavors also to utilize this normally undesirable
and 3.
effect to advantage. Wow, like ?utter, is a periodic change
FIG. 2 is a side elevation of the apparatus of’ FIG. 1,
in frequency of the tones ‘being reproduced, but occurs at
showing details of the tape transporting mechanism. Cer
a much lower rate per second, and to the listener it pro
tain items, such as the tubes and power transformer have 60 duces an unpleasant musical effect which can best be
been omitted from FIG. 2 for the sake of clarity. FIG. 3
described as a periodic “out of tune-mess.” If the amount
is a bottom view of the same assembly, and like characters
of frequency shift is not enough to be considered out of
are used to indicate like parts in the three ?gures. The
tune, still the effect is unpleasant, due to the fact that it
router 8 is resiliently mounted upon therchassis plate 1,
is repetitive and monotonous.
and on the motor shaft is mounted a pulley 31 having 65
In accordance with the invention, certain types of wow
two grooves and carrying two drive belts 30. These belts
may be used to advantage. In an orchestra or pipe organ,
turn a large pulley 29, which also has two grooves. The
the frequency difference between instruments or pipes
pulley 29 is mounted upon a shaft 24, upon which the
sounding the same musical note will usually fall between
capstan 10 is mounted. The shaft 24 maybe supported by
two cycles or beats per second to a fraction of a cycle per
a ?rst bearing 24A where it passes through the chassis, 70 second. If the beat is much over two pets-second the
and by a second bearing (not shown) at the end oppo
tones begin to sound out of tune, at least in the octaves
site the pulley 29. A small pulley 25 is also mounted
near middle C, where the ear is quite sensitive to pitch
upon the shaft 24, which by means of a belt 26, drives
di?erences. As previously described, changes in tape
the large pulley 27. The pulley 27 is mounted upon a
velocity in this invention produce in effect musical beats
shaft 28 which passes through the chassis panel 1, and 75 due to vector additions and cancellations in ‘the pickup
occur at a rate slower than approximately two cycles per
second, will enhance the ensemble by the production of
musical beats such as are heard in an orchestra or pipe
organ. In the present structure there are a number of
factors which contribute to the wow, and which can
The overall wow pattern of the pressure rollers, the pulley
16, and the drive belts 30 is so complex that it cannot be
identi?ed as a repetitive pattern, thus removing any wow
monotony from that source. In considering the prac
therefore be employed to enhance the ensemble e?ect
These factors are:
(1) Motor speed
(2) Rotation speeds of pressure rollers
(3) Rotation speed of pulley 16
(4) Rotation speeds of belts 30
tical operation of a system in accordance with the inven
10 tion, another factor regarding the wow must be con
Rotation speeds of the pulleys 2S and 27 do not con
tribute much because the load presented by the tape
magazine is light. The load on the tape which is presented
by the tape magazine itself is insulated from the enclosed
tape loop, by means of the pressure roller 12 and the
capstan. With the line voltage stability normally en
countered, the constancy of motor speed rotation produces ~
no noticeable wow.
However, a controlled amount of
wow may be introduced intentionally by periodically intro
ducing a small value of resistance in series with the motor
winding and the line. Thus, in FIG. 2 a simple switch 8A
automatically operated, can be used to periodically short
circuit a series resistor SE at intervals of approximately
once per second.
The resistance can be made variable, so
that the degree of the effect is under control of the player.
Since rubber tired pressure rollers have a tendency to
cause wow, even when carefully made, it is desirable in
the present structure, to make their contribution as non
periodic as possible.
vention, two similar belts 30 are used, running on two
double pulleys 31 and 29. The wow pattern is altered
by the use of two belts, in a manner similar to that de
scribed above in connection with the pressure rollers.
heads. Small changes in tape velocity, therefore, which
Suppose that pressure rollers 11
sidered. As is well known, wow as it is normally known
in phonograph or tape reproduction, is a slight rising and
falling in the pitch of any tone being reproduced. At any
instant therefore, the actual pitch of a tone may be
either ?at or sharp to the true or average pitch of the tone.
The same of course is true in this device, but it must be
remembered that the listener does not normally hear the
tone from a single reproduction, but from multiple re
productions which are being heard simultaneously. Thus,
if at any instant one reproduction is sharp, another may
be on average pitch, and another may be ?at to the
average pitch. Musically, this is precisely what is hap
pening when several instruments or organ pipes sound the
same note simultaneously. Therefore, it will be seen
that random wow contributes greatly, and in a number
of ways, to the ensemble effect generated with the present
The importance of the spacing between the heads along
the path of the magnetic tape has previously been men
tioned. A more detailed discussion of various pertinent
dimensions follows. In one structure the following di
mensions were used. The diameter of the capstan 110
was .318 inch and the circumference was one inch. The
rate of revolution of the capstan was six per second.
The tape travel, therefore, equalled six inches per sec
ond. In order to make the ?rst signal pickup occur as
soon as possible after the onset of the organ tone, the ?rst
pickup head 19 may be placed as close as possible to the
approximately doubled in the worst case, and it will be
record head 18, in this case 3/: inch. The second pickup
come noticeable and monotonous, due to its frequent
head 20 should be placed so that its distance from the
repetition. But suppose that one roller is ten percent 40 record head is not an even multiple of the distance be
larger in diameter than the other. The wow contributed
tween the record head and the ?rst pickup head. This is
and \12 each contribute a small amount of wow, which
when taken alone is within the acceptable limit of wow.
But suppose that both rollers are the same diameter and
are therefore turning at exactly the same speed, for ex
ample, one revolution per second. The wow will now be
by the two rollers taken together will coincide approxi
mately every tenth revolution. If one revolution takes
approximately one second, then the pattern will be re
peated not oftener than once in ten seconds. This is so
long a period that the car will not identify it as a monot
onous pattern. The pulley 16 should have a diameter
different from the diameters of the rollers 11 and 12 for
the same reason.
The pulley 16, and the rollers 11 and 12 are all mount
ed upon free turning bearings 23. The pulley 16 serves
a double purpose, and should be made of material such as
brass, so that it will have a relatively high mass. It serves
as a mechanical low pass ?lter, so as to smooth out ir
regularities in the movement of the magnetic tape, and
also provides a large radius for the turning of the tape as
as it begins its return trip past the heads to the capstan.
done so that successive recordings picked up by the ?rst
and second pickup heads do not come at the same instant,
since this would produce a monotonous repetitive pat
tern, which is not characteristic of natural reverberation.
For the same reason the distance from the record head
to the third pickup head 21 is not an even multiple of
the spacing to either of the ?rst two pickup heads. The
50 distance chosen for the second head may be 2% inches
and for the third head 4 inches.
The location of the erase head 15 is not critical, and is
approximately as shown in FIG. 1. The pulley 16 should
be placed as close as possible to record head 18 as shown.
Similarly, the last pickup head 21 should be as close as
possible to capstan 10 and pressure roller 11. Suitable
diameters for the pressure rollers are 1% inches for roller
12, 1% inches for roller 11, and 1% inches for pulley 16.
Note that there are no small radii anywhere in the en
It has been mentioned that the rotation rate of the
closed tape loop from the roller 12 to the roller 11, which
capstan is selected to lie between six and seven revolu
contributes to the smooth movement of the tape. The 60 tions per second, so that any unintended variation in the
tape which is stored in the tape magazine, since it is a
capstan rate would sound like vibrato instead of wow.
continuous loop, must of course have a splice. Since the
It is also possible to equip the capstan shaft with some
splice is stiffer than the rest of the tape, it will cause a
kind of variable load to arti?cally introduce vibrato, by
momentary frequency shift if it passes a small radius any
periodically changing the rate of shaft revolution. This
where in the enclosed tape loop. When the pulley 16
is at least 1% inch in diameter, the passage of the splice
is almost imperceptible, even when a steady tone is being
may be done in any convenient way that causes the load
to change during the rotation of the shaft.
It may be
done mechanically, or as shown in FIG. 2, by means
of a magnetic brake 24B which loads the shaft 24. By
Another important source of wow in this structure is
applying suitable signals to the brake 2413, the amount of
the drive belt 30. A soft ?exible belt should be used 70 loading may be changed in degree, or turned off at will.
here such as rubber, but often the belt rotation itself
It is also possible to obtain an effect similar to vibrato
will introduce a small amount of wow which occurs with
every rotation of the belt. Due to slight irregularities
in belts, the rates of rotation of two similar belts will
seldom be the same. Therefore, in one form of the in
by placing the pickup heads at such distances from the
record head that the successive reiterative recordings and
re-recordings of the signal will occur at vibrato peri
odicity, for example six per second. In this case the
second and third pickup heads should be spaced at dis
tances which are exact multiples of the distance from
the record head to the ?rst pickup head. For example,
the four heads can be spaced one inch apart.
This ar
spective, effects as well as true spatially discriminatory
recording and reproduction. A number of physical ar
rangements of the ampli?ers and speakers which may be
employed to achieve this effect are shown in FIGS. 4, 5,
6, 7, 8 and 9. FIG. 5 illustrates one arrangement where
rangernent also permits the player to obtain a musical
in both ampli?ers 76 and 78, and their associated speak
effect resembling that obtained from a marimba, by play
ing successive, rolling, staccato chords on the organ.
ers 77 and 79 are installed in the organ console, with
one speaker mounted in the front wall of the console and
The notes thus played are repeated six times per second
the other speaker installed in the back Wall. FIG. 6 is
during the period of die away, and resemble the percus 10 similar to FIG. 5 excepting that the two speakers are
sive notes of the marimba or other similar percussive
mounted in opposite end walls of the organ console.
instrument. The fact that this arrangement requires
equal spacing of the heads, while that best suited for
the ensemble elfeot requires unequal spacing of the heads,
The latter arrangement provides somewhat better spatial
separation of the tones. In FIG. 7 the ensemble and
reverberation ampli?er 78 and its speaker 79 have been
does not mean that the two features cannot be used in 15 installed separately in a tone cabinet 93, while the
the same structure.
By providing multiple heads, some
organ ampli?er 76 and speaker 77 are in the console 81.
This is a preferred arrangement, because the tone cabinet
and organ can be placed on opposite sides of the listening
area for maximum stereophonic effect. Gain control 80
of which are evenly spaced, and some of which are un
evenly spaced, either of the desired elfects may be used,
by means of selection switches which short circuit the
undesired heads.
Another desirable feature of the system of the inven
serves the same function as in FIG. 4.
In FIG. 8, organ ampli?er 76 and its speaker 77 have
‘been installed in a separate tone cabinet 84, with the
ampli?er 78 and speaker 79 in another tone cabinet 93.
tion is that it can be used effectively as a self-teaching
device to assist a player in improving his playing tech
nique. When one is playing the organ, particularly
FIG. 9 shows both ampli?ers and both speakers mounted
a beginner, almost complete attention is required merely 25 in a single stereo cabinet, with the speakers mounted in
to play the notes correctly. The player cannot devote
opposite ends of the cabinet to obtain spatial separation.
much of his attention to critically listening to the musical
It might be thought that the arrangements shown in FIGS.
elfects which he is producing. If, therefore, he is able
8 and 9 are better than those in which the organ ampli
to devote his entire attention to listening to a piece which
?er and speaker are mounted in the organ, but such is
he has just played, he can by correcting the mistakes 30 not necessarily the case, although it is probable that bet
which he hears, markedly improve his own playing. The
ter bass reproduction would result therefrom. Actually
present structure permits the player to do that.
the best arrangements are those in FIGS. 5, 6 and 7, be
In the system ‘of the invention illustrated in FIGS. 1
cause here the organ speaker 77 is mounted in the organ
and 4, the magnetic tape is stored in a tape magazine 9.
console. This gives rise to a pleasing phenomena which
While for the purposes of the invention thus far described, 35 is explained as follows: The vibrations from the speaker,
a very small continuous tape loop would suffice, there
especially from the bass notes of the organ vibrate the
are two principal reasons for using a much longer tape
console and the keyboard to such an extent that the
loop, with the excess tape stored within a magazine dur
player can feel the vibrations in his hands, as he plays.
ing operation. First, the matter of wear makes it un
This, in some way, enhances the feeling of bigness and
desirable to use a short tape loop. Since the tape mech 40 grandeur imparted to the organ tones which is probably
anism is in operation continuously while the organ is
due to a psychological reaction related to the fact that
being played, the tape should be long enough so that it
we associate physical vibration sensations with the music
does not have to be replaced too frequently due to wear.
from pipe organs in large reverberant enclosures. There
Second, in order to utilize the self-teaching feature,
fore, the best results are achieved with the system of the
invention when the organ speaker 77 is installed in the
one or two musical selections can be played before the
organ console. Speaker 79 may be mounted either in
tape begins to repeat. Experience indicates that if
the console or separately, as shown, although better spa
from two to three minutes of tape is provided, this
tial effect is probably obtained when it is mounted sepa
will su?ice. It tends to defeat the purpose of the system
rately in a tone cabinet.
as a self-teacher if the player has to wait as much as four
FIG. II shows a simple arrangement, wherein a single
or ?ve minutes to hear what he has played. Two and
ampli?er 76 and single speaker 77 are used to reproduce
a half minutes seems to be about the optimum time.
both the direct organ signal, and the ensemble and rever
With a tape speed of six inches per second, one minute’s
beration signal. FIG. 11 is to be used in connection
playing requires thirty feet, and a total of seventy-?ve
with FIG. 4, and terminal A of FIG. 11 corresponds to
feet of tape is therefore employed.
55 terminal A of FIG. 4. Likewise, terminal B in FIG. 11
To use the device as a self-teacher, the organ is played
corresponds to terminal B in FIG. 4, all the equipment
for a period of approximately two and one~half minutes
and circuit above terminals A and B in FIG. 4 having
with switch 83 in FIG. 4 in the closed position. At the
been, omitted from FIG. 11. Variable resistance con
end of this period the switch is opened. This stops
trol 86 in FIG. 11 makes it possible to adjust the relative
the bias oscillator 73, and removes erase voltage from
head 15, and bias voltage from head 18. The signals 60 amounts of direct organ signal, and ensemble and rever
beration signal, transmitted to the ampli?er 76. Its
which are stored on the tape will now be picked up by
musical function is similar therefore to that of control
heads 119, 20 and 21 and reproduced in speaker 79. No
80 in FIG. 4. While the arrangement in FIG. 11 does
sound will come from speaker 77, but the tones coming
impart reverberation, and some ensemble to the organ
from speaker 79 will have ensemble and reverberation,
enough tape must be stored in the magazine so that
although the stereophonic reproduction will be lacking.
The equipment will play the two and one-half minute rec
tones, the spatial feeling of stereophonic reproductoin is
In the system disclosed herein the ensemble and rever
ording over and over until the switch 83 is again turned
beration effects are obtained through use of magnetic
to the ON position, and the equipment is thus made ready
tape recording techniques, but it will be appreciated that
for another recording.
70 any type of recorder may be used to obtain similar
It has been stressed that the stereophonic reproduction
effects, so long as there is a moving recording medium
of the ensemble is an important feature of this invention,
such as, for example, a disc having a wax or rubber
because of the seeming movement of the tones in the
surface, so long as there are discrete pickup points, either
ears of the listener. The term “stereophonic” as here
magnetic, electrostatic, or mechanical.
used, includes simulated three dimensional auditory per 75
Although a number of specific arrangements for prac
ticing the invention have been described above, it is not
ing members, said electrical circuit also including means
for attenuating high frequency signals relative to low
frequency signals, and an adjustable attenuator coupling
the series of reproducing members to the recording
intended that the invention be limited thereto. Accord
ingly, any and all modi?cations, variations or equivalent
arrangements falling within the scope of the annexed
member to establish a reentrant loop in which the attenu
claims should be considered to be a part of the invention.
ator provides a controlled amount of gain within the
What is claimed is:
reentrant loop,
1. In combination with an electronic organ having a
5. A stereophonic musical device including in com
tone generator for providing ?rst electrical signals cor
bination a unit having a tone generator and providing a
responding to musical notes, delaying means coupled to
the tone generator and arranged to provide successively 10 combined electrical signal output representing musical
notes, at least two spaced speakers, a ?rst signal channel
delayed duplications of the ?rst electrical signals, at suc
coupling the combined output from the musical unit to at
cessively later ?xed mean times, said delaying means in
least one of the speakers as a ?rst electrical signal, a
cluding means for introducing a continuous superimposed
second signal channel responsive to the combined out
phase change into each of the duplications for producing
essentially random phase shifts of the duplications with 15 put from the musical unit and providing therefrom to at
least another of the speakers a second electrical signal,
respect to the ?rst electrical signal, and means combining
said second signal channel including means for introduc
the duplications into a second electrical signal, whereby
ing a continuously variable phase shift of the signals‘
the simultaneous reproduction of said ?rst and second
passing therethrough having at least one substantially
electrical signals creates an effect of musical ensemble
?xed delay interval relative to the ?rst electrical signal
and reverberation.
whereby the combined reproduction of the electrical sig
2. In combination with an electronic organ having a
nal by the speakers produces the effect of musical en
tone generator for providing ?rst electrical signals corre
semble and reverberation.
sponding to musical notes, means for creating reverbera
6. A stercophonic musical system including a tone
tion and ensemble effects coupled to the tone generator,
said reverberation and ensemble means producing second 25 generator for providing an initial output signal, at least
two spaced speakers, one of which is responsive to the
electrical signals representative of the ?rst electrical sig_
output signal from the tone generator, and a reentrant
nals and each having a continuous random oscillatory
loop circuit including recording and reproducing means
phase change e?ect, said reverberation and ensemble
coupling the output of the tone generator to at least one
means also including circuits for successively repeating
the second electrical signals at selected unlike intervals 30 other of the speakers, the circuit including means for
with further continuous random phase change effects,
continually varying the recording and reproducing rates
and means simultaneously reproducing the ?rst and sec
across a range of phase values, the reproducing means
nal recorded thereon, a recording device associated with
tion effect in the musical tones provided from an elec
providing multiple signals at ?xed delay intervals which
ond electrical signals to produce ensemble and reverbera
are subject to the variable phase shifts control means
tion e?ects.
3. A controllable musical device responsive to musical 35 coupled to maintain the recording medium continuously
with the ?xed delays being selected to correspond to
tones for creating ensemble and reverberation e?ects in
reverberation times and with the phase shift introducing
cluding the combination of a cyclic recording medium,
ensemble effects when the output and recombined signals
means for moving the recording medium with random
are reproduced simultaneously by the speakers.
variations from a nominal rate, the random variations
7. Apparatus for providing a controllable reverbera
constituting continuous phase changes in an electrical sig 40
tronic musical system, the apparatus including the com
bination of a controllably movable recording medium
control means coupled to maintain the recording medium
continuous phase variations, a number of reproducing 45 continuously,
moving at a varying rate, the variation in
devices positioned along the path of the recording me
random, a recording member responsive
dium with relatively unequal spacings with respect to
to the electronic musical system for recording signals
each other and the recording medium, each of the repro
therefrom on the recording medium, a number of repr0—
ducing devices reproducing signals recorded on the me
members spaced along the path of movement of
dium with second continuous phase variations, the repro
medium at successively further points from
duced signals being essentially random phase relative to
the recording member, means coupled to each of the re
each other, means coupled to each of the reproducing
producing members provide successively smaller signals,
members for combining the signals reproduced thereby
the spacings between the reproducing members being se
into a single combined signal utilizing relatively unequal
lected to provide desired delay times, a circuit connect
contributions from the reproducing members, a feedback 55 ing
the reproducing members in series and including a
circuit coupled between the combining means and the re
controllable attenuator shunting the series connection at
cording member and attenuation means included in the
a selected point to provide one control of the reverbera
feedback circuit for controlling the rate of attenuation
tion characteristics, and a controllable attenuation cir—
of the combined signal.
cuit coupling the series connected reproducing members
4. Apparatus for introducing controllable reverbera 60 to
the recording member, the controllable attenuation
tory effects in the musical tones provided by a musical
adjusting the loop gain to be less than unity and
device, including the combination of a moving recording
providing a second control of the reverberation charac
medium traveling along a predetermined path, means for
producing a minor random variation in the rate of travel
8. Apparatus for providing a supplementary reverbera
of the moving recording medium, thus to provide a con
65 tion and ensemble elfect in the outputs provided by an
tinuous variation in phase a member coupled to the
electronic musical system, the apparatus including the
musical device for recording the tones therefrom on the
combination of a driven recording medium, a continuous
recording medium, a plurality of reproducing members
drive mechanism for the recording medium providing
each of which is positioned along the path of the record
both a minor random variation and a cyclic variation
ing medium at a successively further point from the re
cording member along the path of the recording medium 70 characteristic of a frequency approximating that of a
vibrato, a recording member responsive to outputs of the
and each reproducing signals in ?xed delay and random
musical system for recording signals on the re
phase relation, an electrical circuit coupling the repro
cording medium, and a reproducing mechanism includ
ducing members in a series relation, the electrical circuit
ing a series of spaced reproducing elements positioned
including attenuation elements for deriving unequal con
tributions from the signals from the individual reproduc 75 along the recording medium for providing a second out
the recording medium and responsive to the musical
tones for recording the tones on the medium with ?rst
put having successively delayed components, each of
the reentrant loop for establishing the rate of attenuation
of signals circulating within the loop, and a second signal
channelcoupled to the reentrant loop for reproducing the
composite signal whereby arti?cial reverberation and en
which continuously changes in accordance with the ran
dom and vibrato variations of the drive mechanism.
9. Apparatus for introducing ensemble effects into
musical tones provided by an associated system, including
the combination of a recording and reproducing mecha
semble effects are produced through a simultaneous re
production of the composite signal and the electrical
signal from the electronic organ.
12. A magnetic recording device for use in conjunction
with an electronic organ in generating special musical
means, the recording and reproducing means being posi
tioned to provide at least one duplication of the musical 10 effects including the combination of a magnetic tape,
means transporting the tape around a loop at an irregular
tones at a substantially ?xed delay interval, and a drive
nism responsive to musical tones, the mechanism includ
ing a recording means, a record member and a reproducing
rate, a recording head positioned adjacent the magnetic
tape for initially recording signals derived from the elec
mechanism coupled to control the record member at a
variable rate for introducing an essentially random
tronic organ on the tape, a plurality of pickup heads spaced
phase change in the reproduced tones, said drive mecha
nism including pressure members engaging the record 15 along the tape in a position trailing the recording head
for producing electrical signals corresponding to the
member which are of like characteristics but not iden
tically matched, a rotary capstan disposed in operative
recorded signals on the tape, an attenuator, an ampli?er
connected serially with the attenuator between the pickup
association with the pressure members, and drive means
including a pair of drive belts coupled to the capstan and
heads and the recording head to de?ne a reentrant loop
which are of like characteristics but not identically 20 including the pickup heads. and recording head within
which signals recorded by the recording head are circu
10. In an electronic organ in which electrical signals
lated with variations in the velocity of the transport of
are generated corresponding to musical notes, means for
the tape producing successively randomly varying phase
creating arti?cial reverberation and ensemble e?ects in
cluding the combination of a first signal channel for direct
changes in the signals being circulated, and means coupled
to the reentrant loop for controlling the level of the circu
ly reproducing the electrical signals generated by the
lating. signals for the creation of special musical e?ects.
organ, a variable phase changing and delay device, the
13. Apparatus in accordance with claim 12, wherein
device including a movable record means, and physically
the tape transporting means includes a rotating capstan
spaced recording and reproducing means associated with
having a rotational speed corresponding to vibrato, and
the record means, and means for moving the record 30 including also means for periodically varying the rotation
means at a continuously randomly varying rate, for pro
al speed of the capstan at a predetermined rate to achieve
ducing successively delayed electrical signals of continu
ously varying phase corresponding to the electrical signals
special music e?’ects.
14. A magnetic recording device for use in conjunction
with an electronic organ for the production of special
generated by the organ, and a second signal channel
coupled to the variable phase and delay device for re 35 musical effects which are dependent upon the velocity of
producing the electrical signals of continuously varying
transport of a magnetic recording medium including the
phase whereby upon simultaneous reproduction of the
combination of an endless tape, a tape transport mecha
phase varying signals along with the original electrical
nism comprising a motor, a capstan driving the tape, a
signals the effect of ensemble and reverberation is
pair of drive belts linked between the motor and the
40 capstan, means for periodically braking the capstan to
vary the velocity of transport of the tape, means for
11. In an electronic organ in which electrical signals
are generated representing musical notes, means for creat
ing arti?cial ensemble and reverberation effects including
selectively and periodically altering the speed of the motor
for varying the tape velocity, means for recording signals
the combination of a ?rst signal channel for reproducing
on the tape, and pickup means ‘for deriving signals from
directly electrical signals produced by the organ, a con 45 the tape having variable characteristics attributable to
tinuously movable recording medium, means for trans
variations in velocity of transport of the magnetic tape.
porting the recording medium with velocities which con
15. Apparatus in accordance with claim 14 in which
tinuously vary over a phase responsive range from a pre
determined nominal velocity, a recording means positioned
along the path of travel of the recording means and
recording electrical signals derived from the organ with
continuously varying phase changes, a plurality of pickup
the rotational speed of the capstan is selected to corre
spond to a vibrato musical effect.
16. Apparatus in accordance with claim 14 in which
an ampli?er and attenuator are connected serially between
the pickup means and the recording head to establish a
means positioned along the path of travel of the recording
reentrant loop in which a variable delay is introduced by
medium trailing the recording means, each of said pickup
the passage of the magnetic tape between the recording
means generating an electrical signal representing the
head and the pickup means.
recorded signals on the recording means, said pickup
17. A magnetic recorder for use in conjunction with an
means being spaced apart whereby the recorded signals
electronic organ for the creation of special musical e?ects
passing adjacent thereto produce successively in each of
including the combination of an endless length of magnetic
the pickup means an electrical signal which is delayed
tape, a pulley about which the tape travels, a capstan en
with respect to the electrical signal applied to the record 60 gaging two oppositely moving surfaces of the tape to form
ing means with variations in the velocity of transport of
a loop between the capstan and the pulley, means rotat
the recording medium producing additional and randomly
ing the capstan at a velocity which imparts variations in
varying phase changes in the electrical signals produced
the velocity of transport of the tape corresponding to the
by each of the pickup means, the phase changes being ran
speed of a musical vibrato, a ?rst idler pulley for en
dom relative to each other, means coupled to the pickup 65 gaging the moving tape with one side of the capstan, said
means for combining selected relative amplitudes of the
first idler pulley having a predetermined diameter, a sec
reproduced electrical signals to form a composite signal,
ond idler pulley engaging the moving tape with the op
means coupled to the signal combining means for apply
posite side of the capstan, said second idler pulley having
ing the composite signal to the recording means whereby
a reentrant loop is established within which the electrical 70 a diameter differing from said predetermined diameter by
at least ten percent, a recording head positioned adjacent
signals circulate with both a delay and continuously var
the loop for recording electrical signals on the magnetic
iable phase shift being introduced with each passage of
tape, a plurality of pickup heads mounted adjacent the
the electrical signals from the recording means to the
recording medium and from the recording medium to
loop trailing the recording head, each of said pickup heads
each of the pickup means, a signal attenuator coupled to 75 being adapted to derive an electrical signal correspond
ing to the signals recorded upon the tape with the elec
trical signals having variable characteristics produced by
variations in velocity of movement of the tape, an ampli
?er, an attenuator coupled serially with the ampli?er be
tween the pickup heads and the recording head whereby
a rcentrant loop is established within which electrical
signals are circulated between the pickup heads and the
recording head with the moving magnetic tape affording a
variable delay in phase shift of the signals within the re
entrant loop, and means for simultaneously reproducing 10
electrical signals circulating within the reentrant loop and
the electrical signals being recorded by the recording head
whereby special musical effects are produced by the inter
action between the signals circulating within the reentrant
loop and the signals being recorded.
18. Apparatus in accordance with claim 17 including
means coupled to the plurality of pickup heads for ?xing
relative selected amplitudes of the signals produced by
with a delay and variable phase shift being introduced
with each passage of the electrical signals from the record
ing means to the recording medium and fromv the record
ing medium to the pickup means, a signal attenuator cou
pled to the reentrant loop for establishing the rate of
attenuation of signals circulating within the loop, switch
ing means for selectively altering the rate of attenuation
within the loop, and a second signal channel coupled to
the reentrant loop for reproducing the composite signal
whereby the signals circulating within the loop are sus
tained to produce a sustained tone in the ?rst signal chan
nel which is extinguished by operation of said switching
means to alter the rate of attenuation within the loop,
21. A magnetic recorder for use in conjunction with an
15 electronic organ for the creation of special musical effects
including the combination of an endless length of mag
netic tape, a curved surface about which the tape travels,
capstan means engaging two oppositely moving surfaces
of the tape to form a loop between the capstan means and
each of the heads for passage to the ampli?er and circula
20 the curved surface, means rotating the capstan means at
tion within the reentrant loop.
a velocity which imparts variations in the velocity of trans
19. Apparatus in accordance with claim 17 including
port of the tape corresponding to the speed of a musical
selectively operable erasing means positioned adjacent the
vibrato, at least one roller means engaging the moving
moving magnetic tape for removing signals recorded
tape with the capstan means, a recording head positioned
20. In an electronic organ in which electrical signals 25 adjacent the loop for recording electrical signals on the
ing arti?cial ensemble and reverberation elfects including
magnetic tape, multiple pickup means mounted adjacent
the loop trailing the recording head, each of the pickup
velocity, a recording means positioned along the path of
travel of the recording medium and adapted to record
electrical signals derived from the organ, \a plurality of
pickup means positioned along the path of travel of the
recording medium trailing the recording means, each of
electrical signals circulating within the reentrant loop and
the electrical signals being recorded by the recording head
whereby special acoustical musical e?ects may be pro
duced through concurrent use of the signals circulating
within the reentrant loop and the signals being recorded.
are generated representing musical notes, means ‘for creat
means deriving an electrical signal corresponding to the
the combination of a ?rst signal channel for reproducing
signals recorded on the tape, means coupled serially be
directly electrical signals produced by the organ, a con
tinuously movable recording medium, means tor trans 30 tween the pickup means and the recording head for estab
lishing a reentrant loop within which electrical signals
porting the recording medium at a predetermined nominal
are circulated, and means ‘for simultaneously reproducing
velocity with minor random variations ‘from the nominal
said pickup means being adapted to generate an electrical
signal representing the recorded signals on the recording
means, said pickup means being spaced apart whereby the
recorded signals passing adjacent thereto produce succes
sively in each of the pickup means an electrical signal
which is delayed with respect to the electrical signal ap
plied to the recording means with the minor variations in 45
the velocity of transport of the recording medium pro
ducing randomly varying phase changes in the electri
cal signals produced by each of the pickup means,
means coupled to the pickup means for combining se
lected relative amplitudes of the reproduced electrical 50
signals to form a composite signal, means coupled to the
‘signal combining means for applying the composite sig
nal to the recording means ‘whereby a reentrant loop is
established within which the electrical signals circulate
References Cited in the ?le of this patent
Stille _______________ .__ May 21, 1930
Trautwein ____________ __ Dec. 27, 1938
Begun ______________ __ Aug. 24,
Goldsmith ___________ __ July ‘18,
Graviel _____________ __ June 20,
Daniels _____________ __ July 21,
Ambrose ______________ __ Apr. 6,
Goodfriend __________ .._ May 29,
Laiferty _____________ __ Oct. 16,
Stibitz _______________ __. Feb. 4,
Halliday _____________ __ July ‘15, 1958
Goldmark ____________ __ Feb. 3, 1959
Jones _______________ __ Oct. 17, 1961
Без категории
Размер файла
2 077 Кб
Пожаловаться на содержимое документа