Table of Contents
Advertisement
At
faster
ATTACK
TIME
settings, substantial
peak
limiting
action
is
produced
with
typical
program
material.
As
the
ATTACK
TIME
is
slowed, the
424A
acts
more
and
more
like
a
pure
compressor,
and
fast
peaks
are
permitted
to
overshoot
more
and more.
Because
overshoots
tend
to
increase,
the
compression
threshold
is
automatically
lowered
as
the
attack
time
is
slowed
to
avoid
clipping
the
Voltage-Controlled Amplifier
(VCA)
used
as
the gain-control
element.
At
the
very slowest
attack times, the release
time
is
also
lengthened by
a factor
of
approximately
4:1
to
assure that
the
424A
is
working
in
a
truly
"averaging"
mode
at these
very slow attack
times,
and
that the
attack
time
does
not get
slower than
the release time.
The
RELEASE
TIME
control
'
s
cales
the
program-controlled
release
characteristic
faster
and
slower.
(The
release
time
is
not constant;
it
is
varied
according
to
the previous
history of
the
program
dynamics.)
To
avoid
having
fast
transients
punch
"holes"
in
the
program
material,
the
release
rate
is
automatically
speeded up
after a large
change
in
gain reduction.
This
creates a
fast
"peak
limiting"
function
which
rides
on
top
of
a
much
slower "compression"
function.
It
is
the
recovery
rate
of
the
"compression"
function
which
is
affected by the
RELEASE
TIME
control.
The
RELEASE SHAPE
switch
further
modifies
the
action
of
the
RELEASE
TIME
control.
It
determines
if
the
recovery
rate
(in
dB/second)
of
the
"compression"
function
is
constant (LINear mode),
or
if
it
starts
out
slowly,
and
then speeds
up
as
it
goes along (Exponential mode),
as
in
Fig.
C-2. (The
fast
limiting
recovery
is
unaffected
by
the
RELEASE SHAPE
switch.)
The
LINear
mode
almost always sounds
more
natural.
OdB
VCA
GAIN
-20dB
TIME
—
Fig.
C-2: LINear
VERSUS
Exponential
RELEASE SHAPES
While
the
initial
release rate (dB/sec)
in
EXPonential
mode
is
approximately
three
times slower than
in
LINear
mode
for a
given setting
of
the
RELEASE
TIME
control,
with
large
amounts
of
gain reduction
it
becomes
approximately
three
times
faster
than
LINear
mode
by
the
time
the
compressor
has
fully
recovered.
12
Hide quick links:
Advertisement
Table of Contents
