Ashly Parametric Equalizers SC-63 User manual
SC-63
/SC-66A
PARAMETRIC
EQUALIZERS
OPERATING
INSTRUCTIONS
ASHLY
AUDIO
INC.
TABLE
OF
CONTENTS
a
Page
1.
INTRODUCTION
/
UNPACKING
2
2.
FRONT
PANEL
LAYOUT
3
3.
BACK
PANEL
LAYOUT
4
4.
INPUT,
OUTPUT,
AND
POWER
CONNECTIONS
4
5.
EXPLANATION
OF
PARAMETRIC
EQ
AND
OUR
CONTROLS
5
6
.
FEEDBACK
STEP
BY
STEP
SETUP
INSTRUCTIONS
7
7.
NARROW
BAND
STEP
BY
STEP
SETUP
INSTRUCTIONS
8
8
.
MEDIUM
TO
WIDE
BAND
STEP
BY
STEP
SETUP
INSTRUCTIONS
9
9
.
APPLICATION
AND
OPERATION
FOR
SOUND
REINFORCEMENT
9
10.
OPERATION
FOR
USE
AS
AN
INSTRUMENT
TONE
CONTROL
11
11.
APPLICATION
AND
OPERATION
FOR
RECORDING
11
12.
APPLICATION
AND
OPERATION
FOR
BROADCASTING
12
13.
APPLICATION
AND
OPERATION
FOR
DISCOTHEQUES
12
14.
APPLICATION
AND
OPERATION
FOR
MOTION
PICTURE
SOUND
&
TV
13
15.
BLOCK
DIAGRAMS
14
16.
CIRCUIT
DESCRIPTION
14
17.
DEFINITION
OF
TERMS
15
18.
TROUBLE
SHOOTING
TIPS
18
19.
SPECIFICATIONS
19
20.
GRAPH
OF
KEYBOARD
/
MUSIC
STAFF
FREQUENCY
NUMBERS
20
1
We
thank
you
for
your
expression
of
confidence
in
Ashly
products.
The
unit
you
have
purchased
is
protected
by
a
two
year
warranty.
To
establish
the
warranty,
be
sure
to
fill
out
and
mail
the
warranty
card
attached
to
your
product.
Fill
out
the
information
below
for
your
records.
Model
Number
Serial
Number
Dealer
Date
of
Purchase
Phone
Salesman
Other
information:
INTRODUCTION
As
soon
as
reproduced
audio
appeared
on
the
scene,
the
need
for
tone
controls
was
apparent;
a
common
problem
has
always
been
loss
of
frequency
extremes.
Early
equalizers
were
simple
bass
and
treble
controls
which
were
used
to
extend
frequency
response
a
bit.
This
type
of
tone
control
is
powerless
when
dealing
with
specialized
acoustical
problems.
Movie
people
of
the
thirties
designed
equalizers
to
deal
with
mid-range
frequencies
and
used
them
for
specific
problems
of
intelligibility.
These
"dialogue
equalizers"
along
with
other
special
effects
devices
such
as
sound
effects
filters
are
examples
of
equalizers
designed
to
solve
specific
problems.
Graphic
Equalizers
were
the
first
universal
tone
controls,
providing
a
piece-
wise
approximation
of
total
frequency
response.
All
of
these
equalizers
have
a
common
limitation,
some
of
the
characteristics
of
equalization
are
fixed.
For
example,
the
center
frequency
and
sharpness
for
each
band
of
a
graphic
are
pre-determined.
This
leads
to
an
immediate
frustration
because
these
characteristics
are
never
exactly
appropriate.
(What
do
you
do
when
you
need
a
fader
right
between
two
sliders
on
a
graphic?)
In
the
late
sixtys,
the
first
parametric
equalizers
were
developed
by
George
Massenburg
at
ITI.
Parametrics
provide
independent
and
continuous
adjustment
of
all
three
possible
characteristics:
amplitude,
center
frequency,
and
bandwidth.
As
a
result,
virtually
any
desired
frequency
response
may
be
obtained
with
no
restrictions
imposed
by
the
equalizer
itself.
The
Ashly
Audio
SC-63
and
SC-
66
A
parametric
equalizers
are
the
result
of
years
of
research
and
development.
They
are
the
most
flexible
and
powerful
tool
yet
developed
for
modifying
audio
frequency
response.
As
such,
they
can
solve
audio
problems
previously
considered
insurmountable,
and
can
provide
tone
control
action
to
exactly
suit
particular
needs.
Of
course,
they
also
require
a
greater
understanding
of
the
equalization
process
than
simpler
tone
controls.
We
ask
that
you
please
read
this
instruction
manual
thoroughly
before
operation
so
that
you
may
realize
all
the
features
and
benefits
that
the
SC-63
and
SC-66A
parametric
equalizers
have
to
offer.
UNPACKING
As
a
part
of
our
system
of
quality
control
every
Ashly
product
is
carefully
inspected
before
leaving
the
factory
to
ensure
flawless
appearance.
After
unpacking,
please
inspect
for
any
physical
damage.
Save
the
shipping
carton
and
all
packing
materials,
as
they
were
carefully
designed
to
reduce
to
a
minimum
the
possibility
of
transportation
damage
should
the
unit
again
require
packing
and
shipping.
In
the
event
that
damage
has
occurred,
immediately
notify
your
dealer
so
that
a
written
claim
to
cover
the
damages
can
be
initiated.
THE
RIGHT
TO
ANY
CLAIM
AGAINST
A
PUBLIC
CARRIER
CAN
BE
FORFEITED
IF
THE
CARRIER
IS
NOT
NOTIFIED
PROMPTLY
AND
IF
THE
SHIPPING
CARTON
AND
PACKING
MATERIALS
ARE
NOT
AVAILABLE
FOR
INSPECTION
BY
THE
CARRIER.
SAVE
ALL
PACKING
MATERIALS
UNTIL
THE
CLAIM
HAS
BEEN
SETTLED.
2
IN/OUT
A
T
a
IN/OUT
A
f
a
IN
/OUT
JL
1
f
(fo)
fi
IN
/OUT
3
INPUT,
OUTPUT,
AND
POWER
CONNECTIONS
This
equalizer
should
be
connected
to
a
3
wire
grounded
outlet
supplying
120
Volts,
50-60
Hz.
Power
consumption
is
12
watts.
The
INPUT
is
a
10K
ohm
active
balanced
type
on
a
standard
stereo
phone
plug.
The
(+)
or
in-phase
connection
is
on
the
tip
and
the
(-)
or
out-of-phase
connection
is
on
the
ring.
When
feeding
the
equalizer
from
unbalanced
sources,
connect
the
signal
hot
to
the
tip
(
+
)
and
the
signal
ground
to
the
ring
(-).
To
use
the
input
as
a
common
unbalanced
type,
simply
use
a
mono
phone
plug
in
the
usual
way.
(See
Definition
Of
Terms,
"Wiring",
page
17.)
The
OUTPUT
connections
are
standard
1/4"
phone
jacks
and
mate
with
a
standard
phone
plug
such
as
a
switchcraft
280.
For
rack
mounted
unbalanced
audio
systems
the
output
ground
may
be
separated
from
the
case
ground
by
using
a
stereo
phone
plug
for
the
output
connection.
The
output
ground
is
then
wired
to
the
ring
of
the
stereo
phone
plug
for
the
output
connection.
The
output
ground
is
then
wired
to
the
ring
of
the
stereo
plugs
rather
than
the
sleeve.
In
this
manner,
ground
loops
in
the
rack
may
be
eliminated.
This
output
can
be
fed
to
a
balanced
input
by
wiring
the
(
+
)
input
to
the
tip,
the
(-)
input
to
the
ring,
and
the
shield
to
ground.
If
this
equalizer
is
used
in
a
monaural
system,
channels
1
and
2
of
the
SC-66A
may
be
cascaded
to
utilize
all
eight
bands
of
equalization.
Connect
the
input
signal
to
channel
1
input,
connect
channel
1
output
to
channel
2
input,
and
take
the
output
signal
from
channel
2
output.
If
the
audio
ground
plug
isolation
is
needed
for
rack
mounting,
use
a
stereo
phone
plug
jumper
to
connect
channels
1
and
2.
d*w)
/—
<
OUTPUTS
)
—
■
^
Rashly
I
SOCH
NT
USA
MODEL
SC-63
CAUTION;
TO
PREVENT
ELECTRIC
SHOCK.
DO
MOT
OPEN
NO
USER
SERVCABLE
PARTS
INSlOf
REFER
SERVICING
TO
QUALIFIED
TECHNICIAN
CONNECT
TO
GROUNDED
OUTLET
TO
PREVENT
FIRE
OR
ELECTRIC
SHOCK.
DO
NOT
EXPOSE
ms
APPLIANCE
TO
RAM
OR
MOISTURE
1/2
AMP
t20VAC,12W,
4
EXPLANATION
OF
PARAMETRIC
EQ
AND
OUR
CONTROLS
A
Parametric
Equalizer
consists
of
several
filter
sections
connected
together
each
capable
of
continuous
and
independent
adjustment
of:
(1)
AMPLITUDE,
(2)
CENTER
FREQUENCY,
and
(3)
BANDWIDTH,
On
the
SC-66A,
these
controls
are
mounted
vertically
below
individual
in/out
switches,
see
figure
A.
On
the
SC-63,
these
controls
are
mounted
horizontally
with
center
frequency
and
bandwidth
controls
grouped
together
and
amplitude
controls
for
three
bands
grouped
together,
see
figure
A-1.
——-j-
Figure
A-1
5
The
(1)
AMPLITUDE
control
(boost-cut)
increases
or
decreases
the
volume
of
notes
selected
by
the
center
frequency
and
bandwidth
controls.
Maximum
effect
is
in
the
middle
of
those
notes,
(see
volume
curve
in
figures
A
and
A-1)
The
(2)
CENTER
FREQUENCY
control
selects
the
frequency
to
be
most
affected.
A
clockwise
turn
moves
the
frequency
up
the
keyboard,
counter
clockwise
moves
it
down.
The
(3)
BANDWIDTH
control
(sometimes
refered
to
as
"Q")
selects
the
number
of
notes
to
be
affected
(approximately
1
to
HO).
Figure
B
shows
the
frequency
response
plot,
above
a
piano
keyboard
of
a
typical
octave
graphic
equalizer
with
the
500
Hz
slider
boosted
12
dB.
n
FIGURE
B
Practically
any
frequency
response
setting
of
a
graphic
equalizer
can
be
duplicated
with
the
SC-63
and
SC-66A
parametrics.
To
get
the
same
response
Figure
B,
simply
set
the
(1)
AMPLITUDE
control
at
12
dB,
the
(2)
CENTER
FREQUENCY
control
at
500
Hz,
and
the
(3)
BANDWIDTH
control
at
1
octave
(see
figure
C).
FIGURE
C
The
net
result
is:
and
the
frequencies
500
Hz,
or
approximately
the
note
"B",
is
boosted
12
dB
1/2
octave
above
and
below
500
Hz
(1
octave
bandwidth)
are
boosted
6
dB
(half
the
maximum
boost).
The
advantage
however,
is
not
that
we
can
duplicate
what
a
graphic
does,
but
rather
extend
our
frequency
response
plot
to
affect
from
nearly
one
note,
to
forty
notes
(.05
to
3.3
octaves).
See
Figure
D.
Other
controls
on
the
SC-66A
(see
front
panel
layout
on
page
3)
include;
power
switch,
master
equalization
in/out
switches,
(NOTE:
Switch
winks
to
green
when
depressed
to
"in"
position.
The
switch
winks
to
black
in
the
out
position,
sets
the
gain
to
unity
and
defeats
all
equalization
in
the
channel)
individual
equalization
in/out
switches,
(NOTE:
Switch
winks
to
amber
when
depressed
to
"in"
position
and
affects
only
the
band
below
it)
gain
control
to
compensate
for
insertion
gain
or
loss
due
to
the
equalization
process
(
+
15
dB),
"peak"
indicator
light
(one
for
each
channel)
monitors
all
potential
overload
points
in
the
channel
and
illuminates
when
the
level
at
one
of
these
points
reaches
6
dB
below
clipping.
FEEDBACK
SUPRESSION
STEP
BY
STEP
SETUP
INSTRUCTIONS
1.
Set
all
gain
controls
on
your
parametric
to
0,
and
make
sure
your
master
equalization
in/out
switch(s)
are
in
the
out
position.
2.
Set
all
equalization
controls
on
your
mixer
to
flat.
3.
Make
sure
no
microphone
is
pointing
directly
into
a
speaker.
4.
If
you
have
a
limiter,
adjust
its
threshold
to
hold
feedback
at
a
low
level.
5.
Estimate
the
relative
volume
relationships
between
your
vocal
microphones
with
individual
channel
sliders
on
your
mixer,
and
use
the
master
fader
on
your
mixer
to
bring
the
system
into
feedback.
Make
sure
all
other
channel
faders
are
turned
down.
Do
not
let
the
feedback
go
uncontrolled
or
you
might
damage
your
high
frequency
drivers!!
6
.
Match
the
first
prominant
feedback
note
with
an
instrument
or
your
ears,
and
check
the
note
against
the
frequency
number
on
page
20
,
and
reduce
system
gain
back
to
about
6
dB
before
feedback.
7.
Select
the
most
appropriate
control
band
(LOW,
MID,
HI).
7
8
.
Set
your
center
frequency
control
to
about
an
octave
below
the
frequency
number
you
select.
9.
Set
the
bandwidth
control
to
full
sharp
(full
clockwise).
10.
Set
the
amplitude
control
of
the
chosen
band
to
+6
dB.
11.
Depress
the
master
equalization
in/out
switch,
and
the
appropriate
band
in/out
switch
(SC-66A
only),
to
the
in
position.
12.
Very
slowly
rotate
the
center
frequency
control
towards
the
selected
feedback
frequency
until
feedback
occurs.
If
feedback
does
not
occur,
increase
system
gain
and
repeat
step
11.
13.
Repeat
step
12
until
you
are
sure
you
have
the
control
centered
on
exactly
the
desired
frequency.
14.
Move
the
amplitude
control
from
+6
dB
to
-6
dB.
15.
Increase
the
gain
on
your
mixer
until
the
next
feedback
sounds.
If
the
same
feedback
frequency
occurs
again,
reset
the
amplitude
control
to
-9
or
more,
as
needed.
16.
Repeat
steps
6
thru
15
to
notch
out
new
feedback
frequencies
for
maximum
gain
before
feedback.
NARROW
BAND
STEP
BY
STEP
SETUP
INSTRUCTIONS
1.
Set
all
gain
controls
on
your
parametric
to
0,
and
make
sure
your
master
equalization
in/out
switch(s)
are
in
the
out
position.
2.
Set
all
equalization
controls
to
flat.
3.
Switch
out
all
other
equalization
devices.
4.
Estimate
the
problem
frequency
area
(use
the
chart
on
page
20
for
help).
5.
Select
the
most
appropriate
control
band
(LOW,
MID,
HI).
6
.
Set
your
center
frequency
control
to
about
an
octave
below
the
frequency
number
selected.
7.
Set
the
bandwidth
control
to
.1
or
sharper
depending
on
what
you
are
trying
to
correct.
8
.
Set
the
amplitude
control
of
the
chosen
band
to
+6
dB.
9.
Depress
the
master
equalization
in/out
switch,
and
the
appropriate
band
in/out
switch
(SC-66A
only)
to
the
in
position.
10.
Very
slowly
rotate
the
center
frequency
control
towards
the
estimated
problem
area
until
it
is
emphasized.
11.
Repeat
step
10
until
you
are
sure
you
have
the
control
centered
on
exactly
the
desired
frequency.
12.
Re-adjust
the
amplitude
control
down
from
+6
to
the
(-)
side
until
the
desired
response
is
achieved.
(Re-adjustment
of
the
bandwidth
control
may
also
be
necessary)
8
MEDIUM
TO
WIDE
BAND
STEP
BY
STEP
SETUP
INSTRUCTIONS
1.
First,
determine
the
frequency
area
of
your
problem.
2.
Decide
how
wide
a
spread
of
frequencies
are
involved,
(see
chart
on
p.
20)
3.
Determine
whether
your
problem
is
an
excess
or
a
deficiency
of
a
frequency
range.
4.
Set
the
bandwidth
control
in
accordance
with
#2
(usually
from
.5
to
3
octaves).
5.
Set
the
amplitude
control
to
accentuate
your
problem
as
determined
in
#3
either
+6
dB
or
-6
dB.
6
.
Turn
the
center
frequency
control
until
your
problem
seems
to
be
at
its
worst
(re-adjustment
of
the
bandwidth
control
may
be
necessary).
7.
Reset
the
amplitude
control
to
correct
your
problem.
APPLICATION
AND
OPERATION
FOR
SOUND
REINFORCEMENT
ITEM:
Monitor
System
Feedback
Control
Probably
one
of
the
most
widely
used
functions
of
parametric
equalizers
is
in
the
control
of
feedback.
The
SC-63
and
SC-66A's
controls
make
it
easy
to
locate
and
notch
out
feedback
frequencies.
It
is
necessary
however,
to
first
be
able
to
understand
the
relationship
between
a
given
pitch
and
its
corresponding
frequency
number.
For
this
reason,
the
graph
on
page
20
showing
a
standard
piano
keyboard
and
music
score
with
the
indicated
frequencies
should
be
refered
to
and
memorized,
especially
if
the
only
test
equipment
you
have
are
your
ears.
The
illustration
below
diagrams
a
typical
monitor
system
hook-up.
After
the
addition
of
an
SC-63
or
SC-66A
to
your
monitor
system,
it
is
possible
to
get
4
dB
to
10
dB
of
additional
gain
before
feedback.
Use
the
narrow
band
step
by
step
setup
instructions
on
page
8
as
a
guide
to
get
you
started.
The
actual
procedure
you
use
may
differ
greatly
after
months
of
experimenting
and
use!
A
TYPICAL
MONITOR
SYSTEM
SIGNAL
PATH
9
ITEM:
Front
System
Speaker
or
Room
Resonance
Problems
and
Feedback
Control
Once
you
become
familiar
with
the
controls
on
your
parametric,
you
will
find
it
much
easier
to
get
the
desired
results
from
your
system.
Use
the
narrow
band
step
by
step
setup
instructions
on
page
8
as
a
guide
to
get
you
started.
NOTE:
The
maximum
volume
of
your
monitors
and
front
system
before
feedback
should
be
determined
if
the
steps
on
page
8
are
followed.
If
you
are
still
not
satisfied,
here
are
some
suggestions
that
might
help:
Place
all
main
system
speakers
and
monitors
such
that
they
do
not
"see"
any
microphones
that
are
to
be
fed
to
them.
Keep
all
guitar
and
keyboard
stage
amps
away
from
vocal
microphones.
Keep
your
stage
volume
as
low
as
possible
so
your
sound
person
has
something
to
work
with
out
front.
Work
vocal
microphones
as
close
as
possible.
When
you
can't
hear
yourself,
have
everyone
else
turn
down
rather
than
you
turning
up.
You
have
already
determined
the
maximum
volume
of
your
PA
system,
and
if
your
fellow
band
members
feel
they
can't
turn
down
any
more,
collect
donations
to
pay
for
upgrading
your
present
system,
ie;
separate
mixes
for
monitor
speakers,
more
directional
microphones,
better
speakers,
etc.
ITEM:
Shaping
The
Overall
Sound
Of
Your
System
To
Improve
Response
Many
PA
systems
use
several
bands
of
graphic
equalization
for
frequency
response
adjustment.
For
many
situations,
one
band
of
parametric
equalization
could
achieve
better
results.
Say,
for
example,
that
the
response
of
a
high
powered
horn
and
driver
that
you
are
using
has
a
noticeable
3
dB
rise
in
the
frequency
area
from
around
1,100
Hz
to
3.500
Hz.
If
you
attempted
to
correct
your
problem
with
a
1/3
octave
graphic
equalizer,
you
would
need
to
move
five
separate
controls.
Visually,
what
looks
like
a
nice
smooth
curve
on
the
front
controls
of
a
graphic,
turns
out
to
be
a
very
bumpy
curve
as
illustrated
below.
This
occurs
because
each
control
has
a
fixed
bandwidth.
Combinations
of
filters
can
not
generate
the
smooth
curve
of
one
variable
filter.
Using
one
band
of
parametric
with
the
frequency
control
set
in
the
middle
of
the
problem
area
(approx.
2,200
Hz),
the
bandwidth
control
at
2
octaves,
and
the
amplitude
control
set
at
-3
dB,
you
get
a
frequency
response
plot
that
will
more
accurately
correct
the
problem.
1
0
Broad
bandwidth
problems
are
much
easier
to
solve
with
an
Ashly
parametric
equalizer.
On
a
graphic
you
can
be
trying
to
manipulate
as
many
as
10
to
15
controls
to
find
the
right
response.
In
fact,
in
many
instances
a
graphic
equalizer
can't
correct
the
problem
anyway
simply
by
the
nature
of
its
design.
Use
the
medium
to
wide
band
step
by
step
setup
instructions
on
page
9
to
assist
you
in
correcting
your
problem.
Remember
to
give
careful
consideration
determining
your
problem,
rather
than
trying
to
find
a
problem
that
may
not
exist!
OPERATION
FOR
USE
AS
AN
INSTRUMENT
TONE
CONTROL
Graphic
type
equalizers,
while
initially
easier
to
operate,
can
not
be
as
accurate
as
the
SC-63
and
SC-66A
parametric
equalizers.
A
parametric
equalizer
gives
unrestricted
control
of
all
the
notes
your
instrument
can
produce.
The
chart
on
page
20
shows
the
relationship
between
the
notes
you
play
and
the
corresponding
frequency
number.
There
should
be
very
little
guess
work
in
deciding
how
you
want
to
equalize
your
instrument
once
this
chart
is
used.
Most
musicians
are
already
familiar
with
the
terminology
A
=
490
Hz.
By
learning
the
numbers
of
other
notes,
you
take
the
guess
work
out
of
knowing
where
to
set
the
controls
on
your
parametric.
A
common
problem
with
many
instruments
is
uneven
response
from
low
to
high
notes.
On
string
instruments
you
usually
have
one
or
more
strings
that
are
not
as
loud,
when
picked
or
bowed,
as
the
other
strings.
On
wind
instruments;
mouthpieces,
reeds,
and
even
weather
changes
can
alter
response.
Most
keyboard
players
really
have
response
problems!!
A
general
rule
to
follow
Is:
listen
carefully
to
your
instrument
and
determine
what
the
response
problems
are.
Try
first,
to
correct
them
with
conventional
means!
Use
equalization
as
a
last
resort,
unless
you
are
trying
to
achieve
special
effects.
The
less
equalization
you
use,
the
easier
it
will
be
to
get
the
"right"
sound
every
time.
Use
the
narrow
and
medium
to
wide
band
setup
suggestions
on
pages
8
&
9
to
get
started.
Patch
your
equalizer
into
your
system
after
the
pre-amplification
stage.
Most
instrument
pick-ups
and
direct
outputs
have
too
low
a
level
to
properly
drive
the
input
of
the
SC-63
or
SC-66A.
An
effects
loop
will
work
well,
or
if
you
are
feeding
a
mixer,
use
a
direct
in/out
patch
point
on
the
channel.
APPLICATION
AND
OPERATION
FOR
RECORDING
The
SC-63
and
SC-66A
can
be
used
to
augment
or
replace
existing
equalizers,
and
compensate
for
system
inadequacies.
Experimentation
with
the
SC
-
63
and
SC-66A
will
yield
better
results
if
the
set
up
suggestions,
trouble
shooting
information
and
reference
graph
information
in
this
manual
is
read.
ITEM:
Critical
Monitor
Speaker
Response
Adjustment
Most
control
room
monitor
speakers
have
fairly
smooth
frequency
response.
However,
room
acoustics
can
radically
alter
the
freqency
response
you
hear.
By
using
an
SC
-
6
3
or
SC-66A
patched
in
before
the
monitor
speakers
amplifier
(or
electronic
crossover,
if
applies)
you
can
compensate
for
room
resonances
or
dead
spots.
For
exact
results,
some
type
of
realtime
analyzer,
or
scope
with
a
frequency
sweep
should
be
used.
ITEM:
Individual
Input
Channel
Equalization
Most
mixing
consoles
offer
some
type
of
equalization
for
each
channel.
Unless
it
is
a
full
parametric
type,
it
can
not
offer
the
complete
flexability
of
the
SC-63
or
SC-66A.
If
your
mixer
does
have
a
parametric
type
equalization
section,
the
SC-63
or
SC-66A
will
add
more
flexability
with
a
minimum
of
expense.
Many
mixers
have
individual
channel
direct
in/out
patch
points
that
will
interface
with
the
SC-63
and
SC-66A.
If
yours
does
not,
a
simple
modification
can
usually
be
done
by
a
qualified
technician.
Use
the
SC-63
or
SC-66A
to
give
instruments,
playing
in
the
same
range,
individuality.
(ie;
boost
the
fundamental
frequencies
of
one
instrument
and
the
harmonics
of
the
other)
By
becoming
familiar
with
the
chart
on
page
20,
guess
work
will
be
minimized.
Use
the
setup
suggestions
on
pages
7
-
9
as
a
general
guide.
ITEM:
Obtaining
Better
Results
From
Reverb
And
Effects
Units
By
patching
an
SC-63
or
SC-66A
right
before
a
reverb
or
effects
unit,
you
can
minimize
high
and
low
frequency
loss.
Boost
those
ranges
before
they
go
into
a
reverb
or
effects
unit
to
compensate
for
losses.
Isolating
frequency
ranges
that
go
into
an
effects
unit
can
also
make
an
effect
more
pronounced.
APPLICATION
AND
OPERATION
FOR
BROADCASTING
ITEM:
Announcer
Voice
Enhancement
Only
full
parametric
type
equalization
as
offered
by
the
SC-63
and
SC-66A
can
modify
voice
frequencies
accurately.
Patch
in
an
SC-63
or
SC-66A
after
the
voice
microphone
has
been
pre-amplified.
Determine
the
frequency
range
of
the
announcers
voice
(100
Hz
to
500
Hz
fundamental,
800
Hz
to
2,500
Hz
presence
area).
Cut
frequencies
above
and
below,
and
boost
fundamentals
for
warmth,
or
boost
the
presence
area
for
definition.
Experiment
with
bandwidth
settings
to
match
the
exact
range
of
the
announcers
voice.
Sibilance
problems
(8,000
to
12,000
Hz
range)
can
be
notched
out
without
affecting
the
overall
sound.
Use
the
step
by
step
instructions
on
page
8
as
a
guide.
ITEM:
Record
Wear
Equalization
Correction
After
several
plays,
a
record
loses
its
high
frequency
response.
The
SC-63
and
SC-66A
can
be
tuned
to
bring
back
some
of
that
lost
high
frequency
without
altering
frequencies
that
are
still
ok.
Use
the
setup
suggestions
on
page
9
as
a
guide.
APPLICATION
AND
OPERATION
FOR
DISCOTHEQUES
Graphic
type
equalizers,
while
initially
easier
to
operate,
can
not
offer
the
unrestricted
tone
control
of
the
SC-63
and
SC-66A.
Old
time
radio
effects,
bass
guitar
emphasis,
frequency
selected
voice
over
effects,
and
modified
speaker
response
curve
settings
represent
only
a
few
of
the
many
1
2
possibilities.
Experimentation
with
the
SC-63
and
SC-66A
should
only
be
done
after
you
are
completely
familiar
with
all
the
controls.
Note:
The
SC
-
63
and
SC-66A
offer
complete
equalization
control,
and
this
same
complete
control
in
the
wrong
hands
can
destroy
a
speaker
system.
ITEM:
Placement
Of
An
SC
-
63
Or
SC-66A
In
A
Discotheque
System
The
SC-63
or
SC-66A
must
always
be
patched
into
a
system
before
the
speaker
amplification
stage,
and
after
the
pre-amplification
stage
of
"a
mixer.
(an
effects
loop
or
somewhere
between
your
mixer
and
amplifier
will
work
well)
Use
only
shielded
cable
for
connections
to
and
from
the
SC-63
and
SC-66A.
APPLICATION
AND
OPERATION
FOR
MOTION
PICTURE
SOUND
AND
TV
The
variability
of
every
equalization
parameter
offered
by
the
SC-63
and
SC-
66A
make
its
selection
for
use
in
this
field
an
ex
ellent
choice.
State
of
the
art
technology,
internal
modular
design
and
external
rugged
construction
make
the
SC-63
and
SC-66A
reliable
and
easily
serviceable.
ITEM:
Removal
Of
Unwanted
Sounds
Determine
if
unwanted
sounds
cover
a
very
narrow
range
or
a
medium
to
wide
range,
and
use
the
appropriate
set
up
suggestions
on
pages
8
and
9.
ITEM:
Voice
Enhancement
See:
Application
And
Operation
For
Broadcasting
on
page
12.
Refer
to
other
operating
suggestions
on
pages
9-13*
13
CIRCUIT
DESCRIPTION
The
heart
(and
primary
expense)
of
the
SC-66A
and
SC-63
is
a
unique
bandpass
filter
circuit.
Basically
a
"state-variable"
type,
this
filter
is
trimmed
and
optimized
to
provide
excellent
transient
response
and
a
wide-range
bandwidth
adjustment.
Each
filter
in
the
SC-66A
and
SC-63
can
be
tuned
over
a
50:1
frequency
range
(about
5
1/2
octaves)
and
a
70:1
bandwidth
range
with
no
more
than
a
2
dB
amplitude
error
at
center
frequency.
At
its
sharpest
setting,
the
filter
has
a
"Q"
of
about
35
and
generates
a
response
curve
with
3
dB
points
only
1/20
octave
apart,
making
feedback
control
possible
with
no
audible
side
effects.
The
filters
are
manufactured
as
individual,
plug-in
units
to
make
servicing
easy.
Each
filter
is
placed
in
the
feedback
loop
of
a
summing
amplifier
to
produce
the
desired
frequency
response.
Since
a
separate
summing
amplifier
is
used
for
each
band,
no
interaction
between
bands
occurs.
DEFINITION
OF
TERMS
AS
USED
IN
THIS
MANUAL
ACTIVE
Electronic
circuits
which
use
devices
such
as
transistors
and
integrated
circuits,
and
which
are
capable
of
voltage
and
power
gain
as
well
as
loss.
Circuits
using
only
resistors,
capacitors,
transformers,
etc.,
are
referred
to
as
passive.
AMPLITUDE
The
voltage
level
of
a
signal.
May
be
measured
in
volts
or
decibels.
Generally
corresponds
to
the
volume
or
intensity
of
an
audio
signal.
BALANCED
A
3-wire
circuit
arrangement
in
which
two
conductors
are
designated
as
signal
lines
(+
and
-),
and
the
third
is
a
shield
and
chassis
ground.
The
signal
lines
are
of
opposite
polarity
at
any
given
moment,
and
are
of
equal
potential
with
respect
to
ground.
Balanced
input
amplifiers
are
used
on
all
Ashly
SC
series
products
to
improve
hum
and
noise
rejection.
Jumpering
signal
minus
(-)
to
ground
provides
an
unbalanced
input.
CENTER
FREQUENCY
The
frequency
(or
pitch)
at
which
a
filter
is
most
effective.
In
a
parametric
equalizer,
it
refers
to
the
frequency
where
a
particular
boost/cut
control
has
maximum
effect.
dB
A
unit
by
which
audio
levels
can
be
COMPARED.
Often
thoroughly
misunderstood
are
the
concepts
that
decibels
represent
the
level
of
a
signal
compared
to
some
reference
level
(15
dB
cut
means
a
certain
level
less
than
a
previous
level
-
the
absolute
level
of
the
signal
need
not
be
known),
and
that
decibels
are
a
logarithmic
unit.
Some
handy
numbers
to
remember
when
dealing
with
decibels:
+3
dB
=
Double
Power
+6
dB
=
Double
Amplitude,
Quadruple
Power
+
10
dB
=
10X
Power
+20
dB
=
10X
Amplitude,
100X
Power
dBm
A
unit
of
measurement
in
decibels
where
0
dBm
=
a
power
level
of
1
milliwatt
into
a
600
ohm
load.
Originally
defined
by
the
telephone
company
to
measure
line
levels.
dBV
Decibel
Volts,
an
update
of
the
dBm
definition
where
0
dBV
=
the
same
voltage
level
as
0
dBm,
but
with
no
regard
to
power
or
impedance.
0
dBV
=
0.778
Volts.
This
unit
is
much
more
appropriate
for
modern
audio
equipment
with
high
impedance
inputs
and
low
impedance
outputs.
DISTORTION
Generally
refers
to
ANY
modification
of
an
audio
signal
which
produces
new
frequencies
which
were
not
in
the
original.
Examples
are
harmonic
distortion,
where
a
circuit
adds
overtones
to
a
fundamental
signal,
and
intermodulation
or
IM
distortion,
where
two
frequencies
beat
together
to
produce
sum
and
difference
frequencies.
FEEDBACK
Generally
refers
to
any
process
where
an
output
is
in
some
form
routed
back
to
an
input
to
establish
a
loop.
Negative
feedback
tends
to
be
be
self
stabilizing,
while
positive
feedback
causes
instability.
15
FILTER
A
circuit
designed
to
pass
some
frequencies,
but
not
others.
There
are
three
general
categories
of
filters:
High-pass,
band-pass,
and
low-pass.
The
high-pass
filter
passes
frequencies
above
a
certain
linrt,
the
low-
pass
passes
frequencies
below
a
limit,
and
the
band-pass
passes
one
group
of
frequencies
without
passing
those
above
or
below.
Our
equalizer
uses
band-pass
filters,
crossovers
use
high
and
low-pass
filters.
FREQUENCY
The
repetition
rate
of
a
waveform.
Frequency
is
measured
in
Hertz.
One
cycle
per
second
(cps)
is
one
Hertz
(Hz).
The
higher
a
note
on
a
musical
scale,
the
higher
its
frequency.
FREQUENCY
RESPONSE
Refers
to
relative
gain
and
loss
at
various
frequencies
across
the
audio
band.
May
be
illustrated
by
a
graph
called
a
frequency
response
plot,
usually
graphing
decibels
vs.
Hertz
or
octaves.
HERTZ
(Hz)
The
unit
of
frequency
measurement.
(Formerly
called
Cycles-per-Second:
this
explains
it
perfectly)
HEADROOM
Refers
to
the
increase
in
level
above
normal
operating
level
that
can
be
obtained
without
clipping.
Usually
expressed
in
dB.
IMPEDANCE
Essentially
the
AC
equivalent
of
resistance.
It
describes
the
drive
capability
of
an
output,
or
the
amount
of
drive
required
for
an
input
at
any
given
signal
level.
KHz
Kilohertz.
1,000
Hertz.
LEVEL
The
magnitude
of
a
signal,
expressed
in
decibels
or
volts.
LINE
LEVEL
Meaning
"somewhere
around
OdBV"
as
opposed
to
MIC
level
of
around
-40dBV.
OCTAVE
A
logarithmic
unit
to
compare
frequencies.
+1
Octave
means
double
frequency,
-1
Octave
means
half
frequency.
OHM
The
unit
of
electrical
resistance
or
impedance.
PHASE
Describes
how
well
two
signals
are
in
step.
In-phase
means
that
positive
and
negative
peaks
in
two
signals
occur
together,
while
out-of-phase
means
they
do
not
occur
together.
Variations
in
signal
timing
as
well
as
polarity
can
make
two
signals
in
or
out
of
phase,
or
anywhere
in
between.
Phase
is
usually
measured
in
degrees
where
0
degrees
is
in-phase,
180
degrees
is
out-of-phase,
and
90
degrees
is
in
between
(sometimes
called
quadrature)
.
PREAMPLIFIER
The
first
stage
of
amplification,
designed
to
boost
very
low
level
signals
to
line
level.
Q
A
measurement
describing
the
sharpness
or
broadness
of
a
filter.
16
SHELVING
Describes
an
equalization
action
where
all
frequencies
above
or
below
a
particular
frequency
are
boost
or
cut.
TRANSIENT
A
sudden
burst
of
energy
in
an
audio
signal,
such
as
a
breath
blast
in
a
microphone,
the
sound
of
a
snare
drum,
or
a
deep
scratch
in
a
record.
Transients
frequently
reach
peak
levels
of
10
to
30
dB
above
standard
operating
level,
and
may
cause
distortion
or
even
damage
to
equipment.
UNITY
GAIN
Output
level
=
Input
level.
WIRING,
PHONE
PLUG
AND
XLR
A
stereo
phone
plug
is
wired
+
to
the
tip,
-
to
the
ring,
and
shield
to
the
sleeve.
For
a
mono
phone
plug,
combine
—
and
shield,
and
connect
both
to
the
sleeve.
An
XLR
(3
Pin)
connector
is
wired
+
to
pin
3,
-
to
pin
2,
and
shield
to
pin
1.
Mono
Phone
Plug:
(for
unbalanced
inputs
and
outputs)
Stereo
Phone
Plug:
(for
balanced
in¬
puts
and
outputs)
Sleeve
Tip
Sleeve
Ring
XLR
Type
Connector:
(Male
Shown)
17
TROUBLE
SHOOTING
TIPS
NO
OUTPUT
Check
AC
power
-
is
the
pilot
light
on?
Check
in/out
connections,
are
they
reversed?
Are
you
sure
you
have
an
input
signal?
EQ
CONTROLS
DO
NOT
DO
ANYTHING
Is
the
master
eq
in/out
switch
in?
Maybe
the
bandwidth
setting
is
too
sharp
to
produce
an
audible
change.
Do
not
expect
the
center
frequency
and
bandwidth
controls
to
have
an
effect
if
the
amplitude
control
is
set
at
"0",
or
if
the
in/out
switches
are
switched
out.
PEAK
LIGHT
FLASHES
OR
STAYS
ON
ALL
THE
TIME
If
the
peak
light
flashes,
the
signal
level
to
the
equalizer
is
too
high.
Turn
down
the
gain.
If
it
is
on
all
the
time,
disconnect
the
input
and
output
cables.
If
it
is
still
on,
the
unit
must
be
returned
for
service.
DISTORTED
SOUND
This
will
only
be
caused
by
too
much
signal
(which
will
show
on
the
"peak"
light.
If
the
light
is
not
flashing,
there
is
an
overload
somewhere
else
in
the
chain.
Adjust
the
relative
gain
of
each
component
in
your
chain
to
keep
everything
at
a
comfortable
level.
EXCESSIVE
HUM
OR
NOISE
Hum
will
usually
be
caused
by
a
"ground
loop"
between
components.
Try
using
the
suggested
balanced
input
and
output
hook-ups
if
the
other
pieces
of
equipment
used
in
conjunction
with
your
equalizer
have
balanced
inputs
and
outputs.
Noise
can
be
caused
by
insufficient
drive
signal.
Make
sure
you
are
sending
a
nominal
0
dBV
line
level
signal
to
the
equalizer.
NOTE:
UN-SHIELDED
CABLES,
IMPROPERLY
WIRED
CONNECTIONS,
AND
CABLE
WITH
BROKEN
STRANDS
(SHORTS
ETC.)
ARE
THE
MOST
COMMON
PROBLEMS.
WHEN
IN
DOUBT,
GET
IN
TOUCH
WITH
YOUR
ASHLY
DEALER,
OR
CALL
THE
FACTORY
DIRECT
-
(800)823-6308.
In
New
York
State
dial
(716)544-5191.
1
8
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