Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to a system for panning
apparent audio sound relative to a listening area throuyh
automatic controls. More particularly, the present inven-
tion relates to control systems for audio reproduction
wherein the apparent source oE one or more sounds can be
panned relative .o the listening area.
Various prior efforts have been directed toward
producing apparent sound sources which move relative to a
plurality of speakers as perceived by a listener. The
classic two-channel stereo systems provide this eEfect by
recording from multiple receiving devices into the two
channels which then produce sound movement effects through
the reproduction of those two channels at a plurality of
; :
transducers. Such systems are effectively restricted to
sound reproduction of the actual recordings and generally
utilized only for apparent sound movement relative to two
output speakers. ~
More recently, effects have been directed towards ~ -
obtaining sound which appears to come from any direction
relative to a listener in so-called quadraphonic effects
by situating three or more speakers around the listening
area. One of these means for controlling the quadraphonic
reproduction is through a four-way joystick control by the
operator. Yet another is to cyclically connect the audio
sources to the various speakers so that the sound appears
to continuously rotate around the listening area, one such
system being shown in United States Patent No. 3,374,315
by Gladwin, issued 19 March, 1968. Yet another system
which causes sound rotation between speakers is shown in
United States Patent No. 3,586,783 by Brickner, issued 22
June, 1971, wherein a low frequency audio spectrum is sub-
sonically rotated between low frequency speakers to enhance
"~
,. ,
.
the stereo effect oE the system~ ~n arrangement intended
to improve the distance and reverberation effects for
sound movement is shown in United States Patent No.
3,665,105 by Chowning~ issued 23 May, 1972.
Although the prior art systems have improved the
stereophonic quality of sound reproduction and have
further enhanced the ~uadraphonic effects, the prior art
does not permit the operator to readily select from
prestored quadraphonic e~fects nor does it provide an
arrangement wherein multiple sound sources can appear to
follow preselected apparent sound patterns under operator
or automatic controls.
The present invention is apparatus and methods
for producing apparent sound sources in accordance with
prestored patterns by extensive use of digital circuitry. -
More particularly, the present invention contemplates
introducing audio signals from at least one source to a
plurality of audio output transducers for creating sound
patterns and effects relative to a listener. The genera-
tion of variable control signals causes a shift in levels
for the output transducers and further include a memory
arrangement for prestoring switching patterns indepen-
dently of the audio signals. The prestored patterns can
be selected automatically in a manner corresponding to the
swi-tching pattern from the memory by means of its output
so that apparent sound will be transferred from one or
more sources through the transducers arrayed around a -~
listening area in accordance with the prestored pattern.
This is accomplished by having an output means responsive `
to the control signals and to the switching pattern output ~;
so that the audio signals frorn at least one audio source
t.~.. r~. ,;
~.... s ".
S'I
'.
are coupled into at least two of the audio output trans-
ducers identified by the switching pattern with magnitudes
corresponding to the variable signal level of the control
signals. Further, i-t is generally contemplated that this
invention will accept audio signals from an external
source and selectably couple those signals into
appropriately arranged output speakers. The source can be ;
one or more sir.gle or multi-track recordings, single or
multiple microphones or combinations of these. The inven-
tion is also well suited for controlled quadraphonic
recording of its output and addi-tionally may be provided
with control means whereby an operator can manually direct
a switching pattern. -
In one embodiment, the signals for shifting the
apparent sound as between the transducers is produced as
varying analog levels and switched to the output trans~
ducers as a function of prestored switching patterns from
a memory device. This memory is addressed by the operator
or by automatic means and, as each panning effect of the
analog signal completes a cycle, shifts the output trans-
ducers that are being coupled so as to provide the illu-
sion of sound movement. `~
In yet another embodiment to be described later,the various potentional shifting levels as between trans-
ducers is digitally produced including increasing, -~
decreasing, or fixed levels with this digital sequence
being switched into an analog switching network in accor-
dance with the prestored patterns selected. The prestored
pattern determines which audio transducers will be
selected and the digital position control generates cyclic
.
~ - 3 -
~ .. ..
digital sequences -that are converted to analog levels and
mixed prior to introduction to the quadraphonic trans-
ducers.
In either embodimen-t, the audio source can be any
of those which are already available including multiple
channel sources. Further, both embodiments permit holding ;
of the apparent sound source at any position desired so
that the apparent sound motion can be stopped or caused to
return to its originating position as desired. Still
further, both embodiments permit selection of the fre-
quency of cycling of the apparent sound movement between
transducers.
With respect to the claimed method for producing
apparent sound sources in accordance with a prestored pat-
tern, the present invention contemplates transferring
signals from at least one source as sound patterns and
effects from a plurality of transducers arranged around a
listening area. This method comprises the steps of
generating cycles of amplitude control signals; storing
data reflecting the identity of the transducers that
should be energized for each of a plurality of patterns
~, .. .
and the control signals to be associated therewith; -
selecting one of the stored patterns; and connecting the
audio signals from the source to the transducers iden- '~
tified by the selected pattern with magnitudes
corresponding to the control signals associated therewith.
Accordingly, a primary object of this invention i
is to provide manual or automatic control of apparent
sound movement relative to two or more audio output trans-
ducers.
Yet another object o~ this invention is to apply
extensive digital techniques to the control of sound
- - 3A -
sources which can appear to move through any pattern rela-
tive to the listener or in directions towards and away from
the listener.
A still further object of this invention is to
provide control of various apparent sound sources within
a listening area with minimal disturbance to the listener
p a ~e ~
but with maximum ~rotcn-tal control for the listener.
Another object is to provide controlled switching
of signals from one or more sources into two or more output
devices in accordance with prestored patterns.
A further object is to provide a method and means
for panning audio from one or more sources between two or
more transducers in accordance with preselected patterns.
The foregoing and other possible objects, fea- ;
tures and modifications will be readily apparent in view
of the following description of the preferred embodiments.
Figure 1 is a general system block diagram showing
the interconnection of one or more audio sources into a
plurality of output transducers by means of an audio pan
generator in accordance with this invention.
Figure 2 illustrakes the amplitude control as
a function of time for effecting the pan between at least
two output transducers.
Figure 3 illustrates various potential panning
sequences which can be produced through the use of the
present invention.
Figure 4 shows additional panning sequences
which can especially be realized through the use of this
invention.
Figure S is a block diagram of a first embodi-
ment of this invention.
.
- 4 -
Figure 6 shows detail of the quadrant position
logic for use in Figure 5 embodiment.
Figure 7 illustrates the time based relationship
of one sequence of quadrant selection panning.
Figure 8 provides additional detail of portions
of the pattern sequencer for Figure 5.
Figure 9 illustrates one example of the various
time intervals involved in generation of a figure-eight
pattern.
Figure 10 shows detail of the analog pattern
sequencer and analog mixer for Figure 5.
Figure 11 is a block diagram of the elements in-
volved in a second embodiment of the present invention.
Figure 12 shows the Figure 11 circuitry and data
flow in greater detail.
Figure 13 illustrates the generation of two ana-
log output levels using the circuitry of Figures 11 and 12.
Figure 14 illustrates the X-Y selection of var-
ious potential apparent sound sources available through the
circuitry of Figures 11-13.
Referring to the drawings and particularly to
Figure 1, there is repxesented an audio source 10 which
may be, although not limited to, a conventional four-
channel tape recorder, record player, microphonic system,
or tuner with a corresponding conventional amplifying system.
Four conventional loudspeakers 25 are energized by signals
on audio output leads 22, the combination being designated:
left front LF, right front RF, right back RB, and left back
LB. In accordance with the present invention, the audio pan
generator 11 as shown in Figure 1 couples the audio inputs
12 from the audio source 10 to the loudspeakers 25 to
-- 5 --
r~ S
,
create a host of unu~ual sound effects for the listener
28. One effect, as shown in Figure 1, is the sensation
O f sound, such as a moving train, heading directly towards
the listener 28 and suddenly veering off as graphically
illustrated by the apparent sound source and direction
26. The audio pan generator 11 determines the pattern
the apparent sound source 26 follows, the speed and dir-
ection the apparent source 26 travels r and numerous other
features hereinafter elaborated on.
The audio pan generator 11 contains four
functional components: the digital position control 17,
the pattern sequencer 19, the analog switch 21 and the
control 14. A general discussion of the audio pan generator
11 follows presenting a brief overview of its major features.
The control 14 will be described in terms o~ apparatus to
allow an operator to manually control the audio pan gener- `
ator 11 on leads 16. The control 14 provides speed and
direction controls on branches 16a and 16b, respectively,
pattern selection controls on branch 16c, channel selec-
tion and volume controls on branch 16d, and various other
feature controls.
The digital position control 17 responsive to
operator commands on branches 16a and 16b provides the timing
for the audio pan generator 11 and determines the speed and
initial selection of the direction the apparent sound source
26 travels. The pattern sequencer 19 has a memory containing
sufficient digital information to reconstruct any pattern
selected on branch 16c from control 1~ in order to e:Efectuate
the actual pattern of sound followed by apparent sound source
26. The pattern sequencer 19 also incorporates the speed
and direction values on lead 18 from the digital position
- 6 -
i
control 17 with the pattern memory data and outputs this
combined pattern and feature information onto leads 2Q.
I The analog switch 21 transfers and allocates the audio
: input signals on leads 12 wh.ich are selected by appropriate
commands on branch 16d to the audi.o output leads 22 according
: to the pattern and feature information from the pattern
sequencer 19
In actual operatiQn, the operator genexally
: initializes the control 14 for direction, speed, type of
10 pattern and channels to be used. The d1gital positiQn .
control 17 responds to the speed and direction commands,
.. the pattern sequencer 19 responds to the pattern select
~. command and the analog switch 21 responds to the channels
selected. The timing, direction and speed information
from the digital position 17 is combined wi.th the pattern
information from the pattern sequencer 19 to cause the
analog switch 21 to couple the audio inputs 12 of the
selected channel to the audio outputs 22 in a predetermined
. manner to create the pattern of sound for the listener 28.
Those skilled in the art are familiar wi~h the
.. "panning effect" as depicted in Figure 2~ As an example,
assume that the sound in channel CHl initially originates
from loudspeaker LF, then to listener 28 situated in a
; room 30, the apparant sound source 26 which is the sound
from channel CHl "pans'l or moves from loudspeaker LF to
loudspeaker RF, when the amplitude of sound in loudspeaker
. LF decreases with time, graphically portraye.d on chart 4a
as amplitude curve 43; and, simultaneously, the amplitude
of sound in loudspeaker RF increases with time., as graph-
ically portrayed in amplitude curve 45. At time T, for
example, the amplitude D (.for "decreasing"l is the level
i - 7 -
, ~ .
.: :
o~ sound fr~m channel CHl emanatiny ~rom loudspeaker LF
and the amplitude I ~for "increasin~"l is the level o~
sound from channel CHl emanatin~ from loudspeaker RF. Of
course, when the sound of channel CH1 has moved to
- loudspeaker RF, D is at zero amplitude and I is at ~aximum
amplitude.
In ordex to create the sound e~fect o~ Fi~ure
2, the functional relationshlp of the audio pan generator
ll of Figure l allocates tasks as ~ollo~s: The control
14 selects both the sound from channel CHl from aud~o
source lO and the pattern for the saund to follow for
pann;ng between speakers LF and RF, and control 14 also
selects the speed and d;rection i~e.~ forward or re~erset
of the pan. The digital position control 17 receives
these commands from the operator control 14 and transmits
timing and direction information to the pattern sequencer
19 which combines th~s`information with the pattern
informatlon, i.e. pan from LF to RF. The analQg s~Itch
21 responds to the combïned feature and pattern information,
i.e., pan in a forward direction from LF to RF at a certain
speed; couples the sound from thQ selected channel CHl to
both speakers LF and RF according to the panning ef~ect
shown in chart 40 of Figure 2~ As w;ll be d;scussed laterr
various other features in the control 14 include: home,
hold, cross mode and chase mode commands. The "home"
position is selected by pattern off and reset and results
in direct coupl;ng of channels from the aud~o source~10
to respective speakers 25 as prewired by the user. In
this example, tbe channel to speaker correlation is as
follows: CHl to LF, CH2 to RF, CH3 to ~ and CH4 to RB.
Assuming the pan pattern configuration of Figure 2 where-
in the sound 26 from channel CHl appears at time T to
- 8 -
--` \
3~
;' .
pan from LF to RF, selection of the "home" command causes
the sound 26 to instantly return to speaker LF since
channel CHl normally originates from speaker LF while
the "hold" command freezes the sound 26 at the T position
and prevents further panning. Assume further that sound
from channel CH2 originates in "ho:me" speaker RF. In the
.. ..
"cross-mode" command the channel CHl sound 26, in Figure
1 2 pans from LF to RF while at the same time the sound
from channel CH2, not shown in Figure 2, cross-pans from
RF to LF creating the unusual effect of sound passing each
:- other in opposing directions. In the "chase mode" the
,:
,
. sound 26 from channel CHl pans, as shown in Figure 2, from
LF to RF while the sound, not shown, from channel CH2 pans
. from RF to RB creating the unusual effect of the sound
in channel CHl "chasing" the sound in channel CH2. The
mode of operation for these effects and others will become -
. clear in the following disclosure of two alternate preferred
embodiments.
Two embodiments w~ll be discussed, the first
20 alternate embodiment, during a given time intervall ;
utilizes the panning effect between any two loudspeakers
25 as shown in Figure 2. In Figure 3, some of the two-
speaker pan effects, though not all, created by the first -~
embodiment are shown to be the movement of the apparent
sound source from channel CHl among the various loud-
speakers LF, RF, RB and LB. In the rotary pan effect,
shown in Figure 3a, the apparent sound source from channel ;.
CHl moves in a circular fashion around listener 28. In
time interval Tl, the sound pans from LF to RF; in time
interval T2, the sound pans from RF to R~ and so foxth,
until time interval T4 when tho sound pans from LB to
_ g _ .:
~ .
,
:~
home position LF. The speed of the apparent sound source
from channel CHl around the room 30 is selected by operator
control 14 on pan speed input lead 16a hereinafter discussed.
The direction o~ the apparent sound source CHl îs also sel-
ected by control 14 on pan fe~tures input lead 16b.
The abo~e discussion centered on one apparent
sound source, for example, from channel CHl of ~ud~P
source 10. In ac~ual operation with four channels w~ere~
in channel CHl originates from home speaker LF, channel
10 CH2 originates from home speaker RF, channel CH:3 ori~-
ginates from home speaker LB ~nd channel CH4 ori~nates
from home speaker RB, other sound ef~ects sho~n in Figures
3 (b) - (c) can be created. Figure 3 (b) shows the rotary -
pan in a chase mode wherein the sound in each speaker
chases the sound in the next speaker around the room.
In Figure 3 (b) which shows only time interval Tl, channel `-
CHl pans to RF, channel CH2 pans to RB, channel CH3 pans to ~ -
LF and channel CH4 pans to LB. Figure 3 (c) shows the rotary
pan in a cross mode wherein the sound from the speakers
20 to the left and right of the listener appears to cross.
For example, Figure 3 (c) and 3 (d) respectively illustrate
the first two time intervals Tl and T2. During the time
interval Tl, channel CHl pans to RF while channel CH2
pans to LF and channel CH3 pans to RB while channel CH4
pans to LB. This creates the sound effect, for purposes
of illustration, of two trains passing each other in
opposite directions.
Figure 3(e) illustrates an additional feature
of instantly stopping the pattern movement and freezing
30 the apparent sound sources into a static or hold position
H. This feature is available on pan features input lead
-- 10 ~ `'
.
16b. Thus the operator, who is generally the listener,
; may cause the rotary pan to speed up, to slow down~ to stop, ~ -
- to change direction, or to control the number of circular
passes. Such features apply to the remaining illustrated
two-pan patterns in Figures 3(f) and 3(g) as well as any
other imaginative two-pan pattern programmed into pattern
sequencer 19.
The present invention is by no means limited
to the first embodiment of four channels and two-pan
effects. As will be discussed hereinafter, obvious changes
by those skilled in the art to the present invention r' ''
could create among others the unusual effects shown in
Figure 4.
The first embodiment of the audio pan generator
11 detailed in Figure 5 comprises the control 14, the digital
position control 17, the pattern sequencer 19, and the analog
switch 21. - -
Control 14 as used in this illustration provides
a manual control for the audio pan generator 11 and enables
the operator to manually select various sound effects for
the apparent sound source 26. It will be readily understood
by those having normal skill in the art that control 14
can easily be adapted to remote operation or to control
from other sources such as a computer or the like. The
operator control 14 interfaces the digital position control
17, the pattern sequencer 19, and the analog switch 21 in
the following manner: Output lead 16a delivers a variable
voltage, which can be formed by a potentiometer or any
conventional variable voltage source, to the digital position
control 17. By varying the voltage on lead 16a, the apparent
sound source 26 can be made to speed up or slow down. Output
-- 11 --
leads 16b deliver binary values of "zero" and "one" to the
digital position control 17 which if appropriately selected
"resets", "sets", and "holds" the contents of the binary counter
52 in a conventional manner in order to cause the apparent source
26 to return to a "home" condition, such as by clearing counter -
52, or to a "hold" condition, such as by blocking further CO
50 pulses from counter 52. Output leads 16c access the pattern
sequencer l9~-wikh~la~p~urality of binary commands. These binary
commands are generated in a conventional manner by panel
10 switches and selectors on the operator control 14. The -
commands on output leads 16c select the pattern and the various
effects such as the cross and chase modes. Output leads 16d
access analog switch 21 with a plurality of variable volt-
age signals designed to provide an over-riding manual
control of the volume and mixing of audio signals before
delivery to speakers 25.
The digital position control 17 comprises:
a voltage controlled oscillator 50 for generation of
timing pulses, a memory address counter 52 in conjunction
with a read only memory 57 and a digital-to-analog con-
verter 59 for generation of data necessary to effectuate ~
the panning effect shown in Figure 2, and quadrant posi- -
tion logic 61 for selection of a quadrant A, B, C, or
D in which to pan the sound as also found in Figure 2.
The pan speed input signal generated on lead
16a from operator control 14 applies a variable voltage
into a conventional voltage controlled oscillator such as
the model CMOS 4046 made ~y RCA or Motorola Corporation.
The output on lead 51 is a stream of digital timing pulses
corresponding, in frequency to the voltage signal level
on lead 16a. The timing pulses on lead 51 access a
conventional memory address counter 52 such as CMOS
~ 12 -
,
v~
14516/4080. The purpose of the memoxy addr~s counter
52 is to generate a bïnary address for addressi`ng data
in the read only memory 57 via 53a. The timing pulses on
lead 51 increment or decrement the counte~ 52r depending
on the binary "direction" command on one of the pan
~ feat~re inputs 16b from operator control 14. As will
; be later discussed, whether the counter is being increm-
ented or decremented determïnes whether the apparent
sound source 26 moves in the forward or reverse direc-
1~ tions to listener 28. In circle pan, for~ard = clockwise
and reverse = counterclockwise~
Another bïnary command from operator control
14 on one of the pan feature inputs 16b causes the memory
address counter 52 to ignore th.e timing pulses 51 and
to "hold" or freeze the address counter by disabling
counter 52 in a conventional fashion. Such action
by the operator control 14 stops the panning effect and
the apparent sound source 26 stops moving and becomes
stationary to listener 28 as shown in Figure 3(e). This
unique feature, "hold", places the sound anywhere with-
in the room 30 at the discretion of the operator. The
final feature on the pan input leads 16b is the "home"
binary command. The "home" command resets the memory
address counter 52 to all zeros. This feature enables
the operator control 14 to return the sound to the
original departure speaker which in Figure 3(b) is LF
for channel CHl. All of the above pan features: direction,
hold, and home, enable the operator control 14 to create
a host of special sound pattern and positioning effects.
The memory address counter 52 outputs a data
field 53 which comprises: the five least significant
-`13 -
binary bits as address data field 53a and also as the
midpan data field 53c and the two most significant bits
as the quadrant data field 53b. The address data field --
, 53a accesses a conventional read only memory 57, such
., .
as a Signetics 8223, and causes the read only memory 57
to output one of thirty-two digital amplitude values 58.
Referring now to Figure 2, the time scale TIME
of chart 40 is divided into thirty-two equal time inter-
vals T. These intervals correspond one-to-one for each
memory address on address data leads 53a. At each time
interval T, there exists two amplitude values: I for the
volume of sound in the originating loudspeaker LF and D
for the volume sound in termination loudspeaker RF.
Such values are expressed in binary equivalents, one
value for Ir-`and one value for D, and are stored in the
read only memory 57 at each of the thirty-two memory
address locations.
Referring again to Figure 5, ~Jhen the memory
address counter 52 is incremented by timing pulses on
lead 51, each increment represents the next time interval
T and the next amplitude values of I and D to be output-
ted from the read only memory 57. Thus, the amplitude
curves 43 and 45 are digitally reconstructed at the out-
puts 58 of the read only memory 57 as the sound pans from
LF to RF. When the timing pulses on lead 51 decrement
the memory address counter 52, the values of I and D
are obtained on digital amplitude value leads 58, in
the reverse manner, to effect panning from RF to LF.
As mentioned, the rate at which memory address counter
52 is decremented or incremented is dependent on the
value of voltage on pan speed input 16a.
- 14 -
The digital amplitude values on leads 58
enter a conventional digital-to-analog converter 59 such
as an R-2R resistor network. The digital-to-analog
converter 59 converts the binary values to corresponding
analog amplitude values to be appl:ied over leads 60.
The amplitude values derived are similar to pan curve 40
relationships of I and D on the amplitude scale of Figure
2 showing sixteen amplitude values. D/A converter 59 may
actually be composed of two separate converters programmed
to produce I and D from a common digital input 58.
Such analog amplitude values on leads 60 en-
ter quadrant position logic 61 which is under digital
control of the quaarant data ield on leads 53b. The
purpose of quadrant position logic 61 is to allocate the
analog amplitude values of I and D on leads 60 for the
appropriate pan quadrant shown in Figure 2 as A, B, C
or D. As time passes to listener 28 when the rotary pan
effect has been selected, panning occurs as illustrated
in Figure 3(a) first from LF to RF in quadrant A, then
from RF to RB in quadrant B, then from RB to LB in
quadrant C, and, finally, panning occurs from LB to home
position, LF, in quadrant D during time intervals Tl-T4,
respectively.
Referring now to Figure 6, the preferred em-
bodiment of the quadrant position logic 61 comprises two
conventional analog data switches ADS0 ~nd ADSl manufactured
by RCA (CO 4016A) or Motorola (MC 14016). The analog
data switches A~S0 and ADSl are under binary control
on quadrant data field leads 53b which embrace the
two most significant bits, Ql and Q0, of the data field
on leads 53. The binary truth table in Figure 7(a)
- 15 -
... .. . . . . . , .. : , .,. :
shows the Ql and Q0 values which select the quadrants
A, B, C or D.
Figures 6 and 7 are best explained in conjunc- `
3 tion with each other and by way of illustration. When
panning occurs in quadrant A, the quadrant position logic
61 sequentially receives thirty-two values of I and D
on analog amplitude leads 60~ Since panning is desired
in quadrant A, both Q1 and Q0 are null thereby causing
analog data switches ADS0 and ADSl to sequentially place
10 the thirty-two values of I and D onto leads 120 and 121
while maintaining outputs 122 and 123 null. The ampli-
tude states of the four outputs 120-123 are shown in
Figures 7(b~-(e) as four separate graphs of time Tm
; versus amplitude Amp. Time Tm is segmented into four
major parts, Tl-T4, each part corresponding to the time
required to pan quadrant A, B, C and D, and each major
part comprising thirty-two time intervals T as shown in
chart 40 of Figure 2. The amplitude curves 120', 121', -
122' and 123' illustrate the output values on leads 120,
20 121, 122 and 123.
As mentioned, the memory address counter 52
is seven bits wide thus having a binary capacity for 128
decimal equivalents. The graphs in Figure 7 each have 128
time positions. Thus, as the memory address counter 52,
initially set at a zero position, begins counting up to
decimal 32 only the least significant five bits are acti-
vated and panning for the rotary pan occurs in Quadrant A.
On the thirty-second timing pulse on input 51, the least
significant five bits are null and Q0 which i9 the sixth
bit of data field 53 is set to one. When Q0 is "1" and
Ql is "0", the quadrant position logic 61 switches the value
- 16 -
-
of I onto output lead 122 and switches the value of D
onto output lead 121. In this manner, with the thirty-
. third timing pulse on input lead 51, panning for the
rotary pan effect begins to occur in Quadrant B from
` speaker RF to speaker RB. Similar operations occur for
the next two sets of 32 counts from counter 52 to effect
. panning through Quadrants C and D. When the memory
address counter 52 reaches the decimal value of 127, all
seven bits of the data field 53 are "1" including Ql and
Q0 and the next timing pulse on lead 51 sets all seven
~: bits to the null state or home position for the rotary
pan at LF.
Thus, the position of apparent source 26 isuniquely defined around the periphery of room 30 by the
seven binary bits from the memory address counter 52,
the least significant five bits on leads 53a determine
- one of thirty-two time intervals T and the two most
- significant bits Ql and Q0 on leads 53b select the specific
quadrant A, B, C or D.
The pattern sequencer 19 performs the function
of causing the apparent sound source 26 to follow a pre-
. determined pattern about room 30. The pattern sequencer
19 as shown in Figure 5 comprises a pattern memory 75 for
data storage of pattern path information, a diagonal se-
- quencer 70 for effectuating the panning of sound along the
"~',
diagonals LB-RF and LF-RB in room 30 of Figure 2, a shift
sequencer for effectuating a shift in panning along the
. diagonals at the midpoint 47 of the pan (for example:
panning begins at speaker LB along the diagonal to speaker
.- 30 RF, but at the center of room 30, the panning shifts to ~ .
: 1
.
diagonal LF-RB and finishes panning in speaker LF), and
an analog pattern sequencer 74 for generating the pattern
path information.
The output 62 of the quadrant position logic
61 comprising leads 120-123 enters the diagonal sequenc-
er 70 contained within the pattern sequencer 19, as
shown in Figure 5. Diagonal sequencer 70 comprises
conventional analog switches, such as CMOS 4016 (not shown)
manufactured by RCA, Motorola, etc., which under binary ~ -
command of the operator control 14 on diagonal input lead
~; 16c' enables panning to occur along the diagonals LB-RF ~-
.. . .
and LF-RB as shown in Figure 2.
Referring now to Figure 8, the diagonal sequenc-
er 70 shows two analog switches, symbolically represent-
ed as 500 and 501. The input leads 120-123 in bundle 62
have analog amplitude values 120' and 121' during time ~ --
interval Tl, which corresponds to panning in Quadrant A for
the rotary pan effect. When the diagonal sequencer 70 is
activated by decoding binary control 16c', the analog
20 switches 500 and 501 in a conventional manner set up new
- paths for the analog amplitude values 120' and 121' to follow.
The outputs 120a and 122a corresponding to a LB-RF pan
carry analog amplitude values 120a' and 122a', respect-
ively, as graphically shown. When the diagonal sequenc-
er 70 is deactivated, there is no activation signal on
lead 16c' from the operator control 14 and the values of
D on lead 120 and I on lead 121 pass through unaffected
on connections 500' and 501' to leads 120a and 121a, respect-
ively. In this mode, the diagonal sequencer 70 is trans-
30 parent to the signals on leads 120-123. When the diagonal
sequencer 70 is activated by an activation binary signal
~, .
- 18 -
on lead 16c, then the rotary pan effect is altered into
diagonal panning. Thus, during time interval Tl, ignoring
the shift sequencer 72, panning takes place along the
diagonal LB-RF in room 30.
- Referring hack to Figure 5, the diagonal se-
quencer 70 interfaces with the shift sequencer 72 on
leads 71. Shift sequencer 72 is controlled by binary
signals on the midpan data leads 53c and the shift in-
put lead 16c" from operator control 1~. As shown in
10 Figure 2, a midpan point 47 occurs when I and D are of
equal magnitude at which time a corresponding unique
~` memory address whose decimal value is 16 has been gener-
ated in the memory address counter 52. As shown in Figure `
8, the least significant five bits of data field 53 are
delivered on leads 53c to a conventional binary decoder
510 (such as CMOS 4001 Quad 2-Input Nor Gate Decoding)
residing in the shift sequencer 72. The decoder 510
emits a binary signal when the decimal 16 value exists
on leads 53c.
With the concurrence of binary signals from
the midpan decoder 51G and a shift command on lead 16c" ;
from operator control 14, the shift sequencer 72 creates
such unusual sound effects as the star pan effect in
Figure 3(g). In the star pattern, during the first interval
Tl, the apparent sound source 26 appears to listener 28 to
move towards the center of the room 30 along the LB-RF diagon-
al, suddenly veer, and finish panning along the LF-RB diagonal. ~-
Referring now to Figure 8, the star effect is accomplish-
ed by activating the diagc nal sequencer 70 in the follow-
30 ing manner: The leads 120a ana 122a carry analog values
: -- 19 -- ~:
: :
~Q~
; D on chart 120a' and I on chart 122a', respectively, dur-
ing time interval Tl. These values are transmitted
through the shift sequencer 72 unchanged and appear on
outputs 120b and 122b until a midpan condition arises
from midpan decoder 510. ~t the midpan point 47, the
midpan decoder 510 emits a binary signal which causes
the analog switches 502 and 503 to switch the data paths
to 502' and 503' shown as dotted lines. This transfers
the remaining pan amplitude values 120a' and 122a' to
leads 121b and 123b, respectively. Prior to the mid-pan
condition 47 the outputs 120b and 122b carrying the am-
plitude values 120b' and 122b' effect panning along the
LB-RF diagonal; and when midpan 47 is sensed by desoder
510 panning shifts to the LF-RB diagonal as determined by
the amplitudes 121b' and 123b' on leads 121b and leads
123b, respectively.
Referring to Figure 5, when the diagonal se- -
quencer 70 and the shift sequencer 72 are not activated,
they are transparent to the outputs 62 from quadrant
position logic 61. In that mode, the outputs 62 are the
same as the inputs 73 to the analog pattern sequencer 74.
Referring back to Figure 3(a), and the previous
discussion of the rotary pan effect, special emphasis cen-
tered on sound originating in "home" speaker LB which
panned to speaker RB in time interval Tl. Of course,
in a four-channel audio source, a plurality of different
sounds can emanate from each channel. The primary fun-
ction of the analog pattern sequencer 74 of Figure 5 is
to assign the analog amplitude values on leads 73 re-
presenting the basic two-pan effect of chart 40 to all
channels in a predetermined pattern such that the
four distinct sounds on each channel CHl-4 from the audio
- 20 -
source 10 will pan between the proper speakers LF, RF, RB
and LB to effect the pattern. The pattern is selected
by toggle switch, not shown, or similar conventional selec-
tion device on the operator control 14 which generates a
signal on one of the pattern input leads 16c'''. The
pattern signal on lead 16c''' addresses pattern memory
75, a conventional binary memory, such as a diode matrix,
a read only memory, a read/write memory, a manual switch
set storage or the like. The output of pattern memory 75
on leads 76 control the analog pattern sequencer 74.
Before discussing the analog pattern sequencer
74, an illustrative example would serve to clarify the
effect occurring. Assume the following "home" conditions:
a bell sound from ~B, a horn sound from RB, a drum sound
from RF, and a violin sound from LF. Assume further the
figure-eight pattern of Figure 3(f) is selected. During
time interval Tlr as shown in Figure 9(a), bells would pan
to RB, horns would pan to LF, drums would pan to LB, and
violins would pan to RF. During time interval T2, shown ~
20 in Figure 9(b), bells would pan to LF, horns would pan to ~ -
,~:
RF, violins would pan to LB, and drums would pan to RB.
During time interval T3, shown in Figure 9(c), violins
would pan to RB, drums to LF, bells to RF, and horns to
LB. Finally, during time interval T4, shown in Figure
9(d), all the sounds pan into their respective "home" ` -~
channels.
Referring now to Figure 10, the analog pattern
sequencer 74 comprises four groupings of conventional
analog data switches ASl-AS4, such as CMOS 4016 (RCA CO401~A
or MOT MC 14016). Each grouping contains analog data switches,
- 21 -
not shown, whose function is the set up of various paths
between the inputs designated 120b-~123b and the outputs
generally designated 120c-123c. In each grouping each
input can be connected to each output by means of the analog
data switches. The inputs 120b-123b arrive from the shift
sequencer 72 on bundle 73 and these inputs 120b-123b access
each analog switch grouping ASl-AS4. The outputs, gener-
ally designated 120c-123c, of each analog data switch
grouping ASl-AS4 are interconnected with the analog
mixer 90 in the manner shown and to be later discussed.
The path to be set up by each analog data switch group-
ing ASl-AS4 is determined by the binary control signals
on branches 310-313 from the pattern memory 75 on bundle
7~
Analog switch grouping AS4 is typical of the
other groupings ASl-AS3. The analog switches, not shown,
are arranged such that any input 120b-123b can connect
to any output 120c~-123c~o Analog switch bank AS4
symbolically shows 120b connected to 123c''' and 121b
connected to 122c'''. Thus, analog switch grouping AS4
receives the two-pan amplitude data 73 on leads 120b-
123b: D on input 120b and I on input 121b, and switches
the amplitude value D to output 123c''' and amplitude `
value I to output 122c'''.
By way of illustration~ the aforementioned
figure-eight pan pattern requires the paths as symbol-
ically set up in analog switch groupings ASl-AS4 for
time intervals Tl as shown in Figure 10. During time
interval Tl, the values of I and D appear on leads 121b
- 22 -
... . . . . .
~6~
and 120b, respectively. During time interval T2, the
values D and I would appear, respectively, on 121b and
122b, as shown in the graphs of Figure 7. During all
four time intervals Tl-T4, the pattern interconnections
of the analog data switches for groupings ASl-AS4 xemain
constant unless a pattern other than the figure-eight
sound effect is selected on the operator control 14.
As will be further disclosed, the output bundles
300 through 303 of the analog groupings ASl through AS4
effect the following pans during time interval Tl of
Figure 9 for the figure-eight pattern of Figure 3(e).
Output 300 with I on lead 121c and D on lead 120c effects
an LB-RB pan; output 301 effects a RB-LF pan; output 302
effects an RF-LB pan; and output 303 effects an LF-RF
pan.
Referring to Figure 5, the analog switch 21
performs the function Gf coupling the audio inputs 12
` to the speaker outputs 22 in a manner to effectuate the
chosen pattern and effect. The analog switch in this
embodiment comprises only an analog mixer 90 which performs
the actual switching functions as follows.
- The pattern select output leads 20 from the
- analog pattern sequencer 74 access the analog mixer 90 of
- the analog switch 21. The analog mixer 90 also receives
audio inputs 12 carrying signals from the four channel
audio source 10. The purpose of the analog mixer 90 is
to mix the four channel audio inputs CHl-CH4 into a desired
pattern of pan effects determined by operator control 14
and to deliver the mix to the speakers LB, RB, RF and LF.
The analog mixer 90 detailed in Figure 10 com-
prises four analog mixer banks AM1-AM4. Each analog mix-
-~ er bank contains five conventional analog amplifiers such
- 23 -
- . ~ . : , ,; . . . . .
as 370 and 372 which, for exampler could be those manufactured -
by National (LM 3900). The input bundles 300-303 from the
analog pattern sequencer 74 are interconnected to the analog
mixer 90 as shown. For example, analog switch grouping AS4
accesses each of the analog mixers AM1-AM4 in the following
manner: lead 120c''' access analog mixer AMl, lead 121c'''
accesses analog mixer AM2, lead 122c"' accesses analog mixer
AM3, ~nd lead 123c''' accesses analog mixer AM4. Analog
switch groupings ASl through AS3 are interconnected with
10 analog mixers AM1~AM4 in a similar manner. The four
channels CHl-CH4 on input bundle 12 from audio source t
- 10 commonly access each analog mixer AM1-AM4. The
outputs from analog mixers AM1-AM4 access speakers LB,
RB, RF and LF. Thus, the output from analog mixer AMl
carries the sound "mix" of channels CH1-CH4 to be heard -,
by listener 28 of room 30 in speaker LB as illustrated
in Figure 10.
Analog mixer AMl is representative of the other
mixers. Each of the four analog amplifiers (370) in analog
20 mixer AMl has two inputs. One input (for example, lead ;~
120c) arrives from the analog pattern sequencer 74 and
one input arrives from the audio source 10 (for example,
channel CHl)~ Whether or not the audio signal on channel
CHl is amplified by analog amplifier 370 depends on the
analog amplitude value on the input 120C from the analog
pattern sequencer 74.
The higher the amplitude value on input 120C,
the greater the amplification of channel CHl. Thus, in
analog mixer AMl, two inputs have amplitude values: Lead
120c as shown has an analog amplitude value of D and lead
120" has an analog amplitude of I. Leads 120c' and 120c'''
~ 24 -
1~6~
are at null level and hence their respective amplifiers
370 do not amplify or transmit signals on channels CH2
and CH4, respectively. Channel CH:L is amplified at a
decreasing rate D and channel CH3 is amplified at an in-
creasing rate I. The two amplified signals are mixed at
the common junction 371. Thus, during time interval Tl,
the amplitude of the channel CHl signal decreases from
maximum value to zero as shown on amplitude curve 43,
while the amplitude on channel CH3 signal increases from
zero to maximum as shown in amplitude curve 45. The
remaining analog mixers AM2-AM4 show the mixing of sound
necessary to effect the figure-eight pattern of sound
during time interval Tl. Each analog mixer eventually
accesses one speaker in room 30, and each analog mixer
AM1-AM4 can mix the sound from any of the four input ;:~
channels CHl-CH4. One skilled in the art readily observes
that by adding more analog amplifiers at mode 371, more
input channels from audio source 10 can be mixed. Such
flexibility enables the addition of more channels of sound ~:
20 to the patterns shown in Figure 3. .. .
The mixed sound at junction 371 enters the
fifth analog amplifier 372 in analog mixer AMl. The pur~
pose of analog amplifier 372 is to permit manual control
of the amplitude of the mixed sound before delivery to
a speaker 25 in order to create ad~itional sound effects.
In Figure 1, the apparent sound source 26 travels from
LB to the center of room 30 and then suddenly veers towards
LF. This feature enables the listener 28 who may also ~ :
be the operator of operator control 14 to cause the sound
traveling from speaker LB to start out quiet and hushed
- 25 -
~0~5~
and to grow to a crashing roar as it culminates in speaker
LF. To this end, operator control 14 may include a con-
ventional joystick 350 which, depending on its two-dimensional
position delivers varying voltage amplitudes to the analog
mixers AMl-AM4 on leads 351-354. When the joystick 350 is
centered, the voltage amplitudes delivered on 351-354 are
maximum and equal and the analog amplifier 372 operates
at maximum amplification. In this position, the manual
override of volume provided by joystick control 350 is
transparent to the mixed sound on junctions 371 of analog
mixers AMl-AM4.
The first alternate embodiment has been predom-
inantly described based on the two-speaker pan effect as
shown in Figure 2. The digital position control 17 essential-
g~n~ rateS ~,
ly !~e~erate= the analog amplitude values as shown on chart 40
for the decreasing D and increasing I values between the two
speakers in successive quadrants. The pattern sequenc-
er 19 as described receives the analog two-speaker pan data
and sequences the analog pan data in a predetermined pattern
20 effectuating a plurality of pans between a given set of
speakers for a plurality of channels. The analog switch
21 couples the audio inputs 12 to the speakers 25 in a
manner responsive to the analog pattern data. -
An alternate embodiment of this invention is
shown in Figure 11, the common reference numerals of Fig-
ures 1 and 5 being retained for like parts or components r
and new reference numerals applied to dissimilar compon-
ents or features. Control 1~ communicates over common
output line 16 with the digital position control 17,
30 the pattern sequencer 19 and the analog switch 21. As
before, the analog switch 21 couples the audio source
'
- 26 -
6~
10 with the loudspeakers 25 to create the unusual sound
effects of Figures 3 and 4 in the speakers LF, RF, RB
and LBo Unlike the first alternate embodiment where
the two-speaker analog pan data is generated in the
digital position control 17, the second embodiment
generates analog values in the analog switch 21 and,
as will become clear, is not dependent on the two-
speaker pan data. In this regard, this embodiment may
effectuate panning from one speaker to three speakers
as shown in Figure 4(a~. The most distinctive feature
of this ~mbodiment is the extensive use of digital
processing in a multiplexed and time shared mode.
~igure 11 shows the functional interaction of
i the various components and will be discussed together
with Figure 12 which shows the basic data paths and
timing relationships occurring in the multiplexed and time
shared modes.
In this embodiment, it is again assumed that
control 14 is arranged to permit maintenance of manual
operator control over the audio pan generator 11.
However, the digital position control in addition
to timing, speed, and direction control outputs a stream
of digital pan values corresponding to an increasing value
I or a decreasing value D as found on chart 40 or a maxi-
mum or minimum digital amplitude value. The pattern se
quencer 19 contains a plurality of predetermined pattern
commands which selectively gates into the analog switch
21 the appropriate digital amplitude value from the out-
put stream. The analog switch 21 converts the digital
amplitude value into analog values and allocates theanalog pan pattern among the appropriate speakers.
,:. .
- 27 -
In addition, the digital position control
17 contains a voltage controlled oscillator 600, a sys-
tem clock 604 and a divider 608 for generation of timing
pulses, a multiplex control 610 and multiplexer 620 for
generation of di~ital amplitude values, a read decoder
616 for generating a read signal for the pattern memory 658,
and a counter 618 as a multiplex control. Each of these
components will be analyzed in detail.
The pan speed input leads 16a contain a fine
speed adjustment signal on branch 16a', and a coarse
speed control signal on branch 16a''. The fine speed
control signal on lead 16a' is generated by a variable
voltage source within operator control 14 and accesses
a voltage controlled oscillator 600 such as the model
CMOS 4046 manufactured by RCA or Motorola Corporation
which outputs a variable frequency train of pulses on
lead 602~ That is, the pulse frequency on 602 corresponds
to the voltage level on lead 16a'. The variable frequency
pulses on lead 602 enter a system clock 604 such as the
C~OS 4040 and each incoming pulse on lead 602 advances
~y "1" the system clock 604 which is basically a binary
counter. The variation of voltage on branch 16a' enables
the system clock to increase or decrease the rate at which
the count accumulates within system clock 604 whose data
field output appears on lead 606 and is fed through
branches 606a-606F to the remaining system elements.
The data field output 606 of the system clock
604 is shown in Figure 12 to include 12 binary output
bits SC0-SCll. A brief summary follows concerning
the interaction of output bits SC0-SCll with the system.
- 28 -
.
The values SC3 and SC2 appear on both branches 606d ~:
accessing the multiplex control 610 and branches 606f ~;
accessing the pattern memory 658. The bits SC0, SCl and
SC4 are decoded by read decoder 616 for the particular
state of SC4=0, SCl=l and SC0=1 in which state the
read decoder 616 emits a read command pulse on lead 624
for causing the pattern memory 658 to be read. When the
bit SC4=1 is delivered by the branch 606a to the latch '
register 65~, the latch register 654 loads the pattern
10 code selected in the operator control 14 as represented ~ . '
by data block 720. The bits SCll, SC8, SC5 and SC2 ;:
are collectively grouped on branches 606C which enter a
divide-by-eight circuit 608 wherein the coarse speed
control signal on lead 16a" selectively chooses one of
the SCll, SC8, SC5 or SC2 signals for transmission of that .
signal to the counter 618 on lead 612. The counter 618
increases or decreases'its count at a rate dependent upon
the frequency of pulses entering on lead 612. For example,
if the divide-by-eight logic 608 selects the pulses on ~.
SC2 then whenever the system clock 604 counts up to SC2=0,
SCl=l and SC0=1 the next in~rem~nt will cause the SC2 bit
to become SC2=1 and to increment counter 618 by "1". If
the divide-by-eight logic 608 enables the SC5 lead, how~
ever, to drive the counter 618 then the counter 618 is in-
cremented at a rate eight times slower than the above case
where SC2 provided the driving pulses. Thus, operator
control 14 provides a fine speed control branch 16a' into ~'
VCO 600 and a coarse speed control on branch 16al'. As
will be discussed later, the speed control, as in the first ~:
embodiment, governs the speed at which the apparent sound
source 26 travels to observer 28.
,.
- 29 - :
~: ... .. . .. : . .
.l
As shown in Figure 11, the multiplex control
610 reacts to the data SC3 and SC2 on branch 606d
by sending commands to the multiplexer 620 on leads 614.
The multiplexer 620 also receives digital signals on
branch 622a. The function of the multiplex control 610
is to allow the multiplexer 620 to transmit to leads
626 the following digital values:
1. The true value "TV" of the data
on branch 622a.
2. The complement value "CV" of the
true value TV of the data on branch
622a.
3O To ignore the values on branch 622a
and to generate all "ls" on lead 626.
4. To ignore the values on branch 622a
and to generate all "0s" on lead
626.
The functional arrangement of Figure 12 ela- ~
borates on this interaction. The multiplex control 610 ~ ,
receives inputs SC3 and SC2 from the system clock 604,
these two binary inputs form four discrete decodable
states wherein true ~alue TV corresponds to the "00"
state, complementary value CV corresponds to the "10"
state, all ones correspond to the "01" value and all
zeroes correspond to the "11" value for SC3 and SC2,
respectivelyO The multiplex control 610 decodes the
values appearing on SC3 and SC2 in a conventional manner
to create command signals TV, CV, "ls" and "0s" whereby
these sign~ls cont~ol~mu~tiplexera~0.
Th~ multiplexer 620 comprises conventional circuitry
such as CMOS 4019 Quad AND-OR Select wherein the TV command
from multiplex control 610 causes the multiplexer 620 to
transmit a true value from the data block 710 appearing on
leads 622a created as the counter 618 increases its count.
The nature and function of the data 710 will be fully
- 30 -
explained later. The complementary value command CV
causes the multiplexer 620 to transmit the complement
of a true value ~rom the data 710 (as through the addition
of an inverter 712). The "ls" and the "Os" commands cause
the vultiplexer 620 to output corresponding values of all
"ls" or all "Os", the latter via invertex 713, independent
of the data 710.
It is readily apparent that as SC3 and SC2 are
adYanced from their "00" to "11l' values respectively
corresponding to discrete time intervals tl-t4, the
values M3-M0 appearing on bus 626 varies as shown in
Figure 12. For example, when SC3=1 and SC2=0 as at time
T3 the multiplex control 610 generates a complementary
valuet~ CV command causing the multiplexer 620 to complement ~ -
the data~-~ appearing on lead 622a which at tA is C5=1,
C4-1, C3-1, C2=0 and to deliver the complementary value
CV onto the output bus 626 at T3 as M3=0, M2=0, Ml=0 and
M0=1. I~7~s!:~mportant to note that the counter 618 which
generates the data block 710 operates at a much slower
rate than the multiplex control 610 thus enabling the
multiplex control 610 driven by bits SC3 and SC2 of the
system clock 604 to sequentially load onto the bus 626 -
the values of M3-M0 for Tl through T4 before the input
data 710 to the multiplexer 620 increments to the next
value. Thus, the time interval tA has as a minimum
four sub-time intervals tl-t4.
As shown in Figure 11, the data M3-M0 appear-
ing on bus 626 directly accesses the analog switch 21.
It will become apparent that the data on bus 626 will -
be used to construct either the I or D panning curve as
shown on chart 40 of Figure 2~
,.
- 31 -
In this embodiment the pattern sequencer 19
essentially provides gating co~runands on leads 664 for
the analog switch 21 to selectively gate digital analog
values on the common }~us 626 ~rom the digital position
control 17. The pattern sequencer 19 per:Eorms this
selective~. gating through interaction of a pattern memory
~which contains the pattern path information for
selective gating, the latch register 654 which stores
the pattern code selected by operator control 14 for
10 addressing the pattern memory 658, the quad select logic
650 for determining the quadrant of panningr and for each
channel a position hold switch 662 which prevents the se-
lective gating thereby "holding" the sound at a given
position.
The determination of which pattern the sound
26 should follow occurs in the pattern sequencer 19.
Latch register 654 composed of conventional circuitry
such as, a CMOS 4042 Quad Clocked D-Latch stores the
pattern code for one of many possible patterns as gener-
20 atedrj~L~r example, by conventional ~oggle switches ~ ~:
within the control panel 14 and represented at pattern
code block 720. The latch register 654 loads a given
pattern code 720 and the chase/cross mode at code block
721 appearing on lead 16c from toggle switches, encoder
or the like, not shown, on the operator control 14 for
storage at periodic intervals when SC4=1 appears on
branch 606a :Erom the system clock 604. For example, if
the rotary pattern code is "1111" and the chase pan code
"0" is selected in the operator control 14, then at
30 count SC4=1 this information is gated in and stored
as L4=1, L3=1, L2=1, Ll=l and L0=0. The output L2, Ll
- 32 ~
~o~ s~
and L0 of laxch register 654 directly accesses pattern
memory address positions PM7, PM6 and PM5 of the pattern
memory 658. The pattern memory 658 is a conventional
read only memory such as 1602A PROM made by Intel.
The L4 and L3 values of the latch register 654
enter the Quad Select logic 650 comprising conventional
logic such as CMOS 4019 Quad AND-OR Select. These two -;
bits L4 and L3 are sufficient to define the four quadrants
A, B, C and D. Bits C7 and C6 of the counter 618 represent
the particular quadrant the pattern is panning. Bits C7
and C61also~a¢cess:rthe Quad Select 650 on leads 622b. The
values at SC3 and SC2 from system clock 604 directly ad-
dress the pattern memory 658 at PMl and PM0, respectively~
Thus, in normal operation the relationship among the system
clock 604 and read decoder 616, the latch register 654
and the quad select 650 with the pattern memory 658 is `~
as follows since timin.g among the various entities
is crucial. The quad select data appearing on leads 652
. .
for PM4, PM3 and PM2 changes most infrequently since the ..
quad select 650 is activated by bits C7 and C6 of the -~
counter 618. Bits PM7, PM6 and PM5 of the pattern memory
658 are updated whenever SC4 of the system clock 604 becomes
'l~38thereby activating the latch register 654 to allow entry
. of the address memory bits PM6 and PM5. The update by SC4,
I however, may not change the pattern values if the pattern
input values 720 have not been changed by the operator at ~ .
operator control 14. Finally, the address memory bits PMl
and PM0 changa frequently since they are derived from
bits SC3 and SC2 of the system clock 604. For exam-
ple, when SC3 and SC2 enter the T2 state SC3=0, SC2=1 r .
SCl=0 and SC0=0, the time it takes for the SCl and SC0
, ;~
- - 33 - :
,::
to count up to the "11" state provides ample time for the
SC3=0 and SC2=1 state to address the pattern memory 658
- and to allow for appropriate settling times in the pattern
memory. Thus, when SCl and SC0 reach the "11" state
- and SC4=0 the read decoder 616 emits a signal on lead
624 which enables the pattern memory 658 to output
trigger values XlYl-X8Y8 onto bus 660. In actual opera-
tion the tl-t4 values of SC3 and SC2 shown in data block
722 generate four unique addresses for the pattern memory
658 thereby outputting four different pattern trigger
values appearing on bus 660 wherein Figure 12 shows the
four exemplary values of Xl and Yl in data block 730. These
four values appear sequentially in time on the trigger data
bus 660 as tl-t4.
The position hold switch 662 comprises conven-
tional logic as for example found in the CMOS 4011 Quad 2
input NAND ~ate wherein the ~1 value and the Yl value
normalhy-r-a~eLtransmitted through the position hold switch
662 onto leads 664' and 664'', respectively, in order to
access the analog switch 21. However, position hold switch
662 is under operator control on lead 16F which inhibits
passage of~thebXldand Yl values when 16F is appropriately
enabled. It is understood that there exists corresponding
circuitry for the X2Y2 and so forth up to but not limited
to X8Y8 which as will become apparent correspond to CHl-CH8. ~;
In the present embodiment, the analog switch
21 of Figure 12 couples the audio inputs 12 to the output
speaker leads 22 through use of identical analog mixing
configurations 680 for each channel. Each analog mixer
680 comprises a storage element for storage of the
selectively gated two digital amplitude values from
.. .
- -34 -
.~
the common bus 626, two digital-to-analog converters 686
for conversion of the two digital values to analog values,
- and a voltage controlled amplifier 690 for controlling
the panning effect among the output speakers 25 for a
given channel.
The respective trigger inputs Xl and Yl appear-
ing on branches 664' and 664'' selectively gate in data
appearing on the common bus 626 to their respective Xl
storage 682' and Yl storage 682 ". For example, at time
10 tl, the value appearing on the bus 6~6 is M3=1, M2=1,
Ml=l and M0=0. At time tl, Xl=0 and Yl=l. Note that
although the ROM 658 (trigger) data 660 are read 0=active,
the data are inverted through the read gating resulting in
l=active for the X and Y triggers. A "1" signal on either
trigger input Xl or Yl enables the data on 626 to he
stored in the respective storage 682' or 682''. Thus,
at time tl the Xl storage682' receives the binary value
of "1110" equivalent to a decimal value of "14" and at
tl the Yl storage 682" is not activated. At times t2
20 and t3 both values for Xl and Yl are "1" and thus no ~ -
- values on bus 626 are gated into storage. At t4, however,
Yl goes to "0" and the value on bus 626 at t4, M3=0, M2=0
and Ml=~ and M0=0 is gated into the Yl storage 682'9.
At th~ end of the timing sequence tl-t4, the following
values are sto~ed: Xl=decimal 14 and Yl=decimal 0.
It is apparent that for the next sequence of tl-t4,
i.e., the tB interval, the Xl storage will contain the
decimal 15 and the Yl storage will still contain the
decimal O. These decimal values appear on leads 684'
and 684'', respectively, and access respective digital-to-
analog converters 686' and 686''. In turn, the digital-to-
- analog converters transform the decimal values into analog
- 35 -
. . . . . .. .
5'~
values whic~i appear on leads 688' and 688''. The digital-
to-analog converters can be any of a variety of conventional
types such as an R-2R resistor network. The analog Xl value
on lea 688' and the analog Yl value on the lead 688'' enter
a conven1tional voltage controlled amplifier 690 such as the
Allison VCA 2-5A. The voltage controlled amplifier 690 res-
ponds in the following manner to the Xl and Yl analog signals.
When Xl is varied from zero to maximum analog voltage
and Yl is held at 0 voltage panning occurs from LF to
- 10 the RF speakers. When X is held at maximum analog voltage
and Y is varied from zero to maximum value panning occurs
from the RF speaker to the RB speakerr When Yl is held
at maximum analog voltage and Xl is decreased from a
maximum to zero voltage panning occurs from RB to LB.
W~ Xl is held at zero and Yl decreases from a maximum
' value to zero panning occurs from LB to LF. Thus by merely
controlling the values of voltage appearing on Xl and Yl
the rotary pan effect can easily be created.
Figure 13 shows a detailed circuit schematic
of the position hold switch 662, the storage 682 and the
digital-to-an!log converters 686. Of special significance
are the charts 800 and 802 which show the voltage values
appearing on leads 688'' and 688', respectively. Chart
802 illustrates that there are sixteen values of voltages
in a step function relationship generated exclusively by
the binary values shown in chart 910 of Figure 14. As ~;
the values in chart 910 are generated from "0000" to
"1111", corresponding analog values appear in lead 688.
Chart 800 illustrates the holding of zero during the time
interval.
In addition, by varying both the voltages Xl
and Yl the panning can take place between all four speak-
-- 36 --
ers and sound may be positioned at any of one of 256
unique positions in the room. Xl and Yl each have four
binary bits the combination of the two can address 256
unique positions in the room. Figure 14 shows a 256
grid network 910 positioned between the speakers 25.
The figure shows the result of utilizi~ng the position
hold switch 662 wherein the ope~ator has activated
lead 16f prohibiting the updating of the storage 682.
Since further updating is prohibited, the sound stops
panning and becomes stationery. The pattern memory 658
is capable of handling a plurality of channels. For
illustration purposes eight channels are shown in ~igure
12. Each of these eight channels have different X and
Y analog values corresponding to a different decimal
number between 0 and 15. In Figure 14, channel 1 at
position 900 has a decimal value of 7 for Y while X has
a decimal value of 6. As long as the position hold switch
662 is activated the sound from channel 1 will appear to
originate from position 900 of the grid 910. The re-
maining channels can also be allocated to different andunique positions as shown in Figure 14. The major effect
of this invention is to provide the means in which sound
can be positioned anywhere within a room such as for simul-
ating an actual orchestra.
Figure 4 illustrates other effects that may be
created by the second embodiment. Figure 4(a) illustrates
; a moving wall of sound from speaker LF which can be created
by causing X and Y to both increase from zero ampli~
tude to maximum amplitude on leads 688' and 688'', res-
pectively. The remaining patterns are extensions of the
above discussions.
. ~ .
- 37 -
.
' .
; . . '' :, ' '`, :
.
It should be recognized that the total power
being produced from all four transducers in coupling the
sound from any given input channel preferably is kept con-
stant throughout any quad panning. This power distribution
is handled automatically by the Allison VCA 2-5A mention-
ed for VCA 690 via a panning network which responds to
the X-Y inputs to appropriately control the gain of our
output amplifiers which are coupled to drive respective
output transducers 25. The panning matrix converts the
X-Y coordinate position values to gain control values for
each amplifier coupled to the various output transducers.
The X-Y values define the distance D from the transducer's
position to each of the outputs according to the Pythagorean
! theorem. That is, the gain value for a given distance D
is the cosine value for that percentage of pan. If the
sound is to come entirely from a particular transducer,
D=O and cos 0=1. For half the distance between two trans-
ducers, D=0.5 and cos 45=.707 while complete panning to
the second transducer means D=l and cos 90=0 (i.e~, no
sound pan from the pan originating transducer). As men-
tioned, the 256 potential apparent sound source positions -
are each definable by the data contained in an eight bit
word, four bits each for X and Y. This can be correlated
to gain Vc and power loss P as is illustrated in the fol~ ;
lowing examples.
For the first example, assume four transducers
25 are oriented as shown in Figure 14. Assume further
that the input channel is to be coupled exclus~vely to
transducer #l or from the left ront transducer. This
30 corresponds to a data word of 0000 0000 which specifies ; -
that Dl (the distance from the apparent sound source to
. :
'
f-- ~
transducer #l) is zero so that Vcl=O and P1=Odh where-
as D2-D~ are all equal to or greater than 1 so that Vc
for each is O and no output power ls produced. In the
next example, assume that the apparent sound from one in-
put channel is to come from the center front of the lis-
tening area halfway between transducer #l and transducer ~ -
#2. This corresponds to a data word of 1000 0~00 which
correlates to Dl and D2 both being 0.5 so that Vcl and
Vc2 are both 0.707 and Pl and P2 are both -3db. D3 and
D4 are both greater than one so that Vc3 and Vc4 are
zero. Transducers #1 and #2 are thus each producing half
the power and #3 and #4 are producing none.
As a final example, assume the apparent sound
is to come from the center of the listening area. This
corresponds to a data word of 1000 1000 which correlates
to Dl-D4 all being 0.707, Vcl-Vc4 all being 0.5 and Pl-
P4 all being -6db. Thus transducers #1 through #4 are
each producing one-fourth the total power.
From the basic relationships of the foregoing
examples and the detailed description of the preferred
embodiments, various modifications of the present in
vention become readily apparent. For instance, the panning
network in VCA 690 could be replaced with a network for
decoding the data woxd and producing appropriate operation-
al amplifier gain signals. This could be done by ad- ;
dressing another memory to produce digital bytes into
respective digital-to-analog converters which in turn
control the gain settings of four output amplifiers hav-
ing a given channel commonly coupled thereto. Further,
the amplifiers could each have a buffer arrangement for
storing its gain setting with these buffers being multi-
plexed for a plurality of input channels. The buffers
- 39 -
.. . . - , - , . . . . . . . .
could be digital with separate digital-to-analog convert-
ers for each input or a single capacitive sample and hold
circuit could be included for each output amplifier if
the multiplexer speed is fast enough. In each case, there
would be a complete set of amplifiers for each input chan-
nel, these sets each having the same number of amplifiers
as the number of output transducers.
Under some circumstances, it may even be desir-
able to include circuitry for computing appropriate gain
settings as a function of the distances D defined by the
X-Y data word. This might be arranged to directly load
digital-to-analog converters or to select gain settings
via a table hook-up operation.
Although the present invention has been describ-
ed in considerable detail particularly with respect to the
preferred embodiments thereof, various changes, modifica-
tions and/or additions will be apparent to those having
normal skill in the art without departing from the spir5it
of the invention. For instance, part or all of the sig-
nals provided by control 14 can be provided by the digitaland analog input/output available from computers or auto-
mated control units. Yet another example is that the ,-
read only memories could be replaced with read/write mem-
ories which could further be loaded from external sources,
an arrangement particularly useful for permitting dynamic
changes to the stored patterns.
.,, :, .
- 4 0-
