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These general guidelines are mainly applicable when the
1178
is
used for the limiting of individual signal sources.
For mixed
program material*
a
middle—
of
"the— range setting will usually be
a
good starting point for additional experimentation.
3.4.5
EFFECTS OF RELEASE TIME
This control* too*
may be set
to
accommodate different program
material requirements.
The best adjustment maintains
a
quick
response of the limiter
to
dynamic changes of the signal while
avoiding such affects
as
"pumping" or "breathing."
Again* let
us
examine the behavior with some extreme settings.
If
the release time
is
set very short* the limiter will return
the
gain reduction
to
zero every time the signal drops below the
threshold.
For low
frequency solo passages* such
as
bass
and
drum* this
can occur between cycles or individual notes
and beats.
We would hear the gain come up each
time* and*
with
it*
the softer
passages or background noise.
Extremely short release times may
even introduce harmonic distortion
if the
gain reduction changes
between cycles
.
Setting the release time to
a
very
long
duration will maintain
the initial gain
reduction caused by
a
large amplitude* and the
dynamic range of the passage which follows
is
strongly affected.
If the
gain reduction continues through
a
soft program section*
it
may make this section inaudible because
it*
too*
will be reduced
in
gain.
Also*
short dynamic changes will be ignored due
to the
continuous high level of gain reduction.
The most desirable release time setting for particular program
material can usually be found quickly
by experimentation.
Here,
too* the
effects of varying the adjustment are
more obvious with
individual signals* and
less
apparent with
a
full mix.
As
with
the
Attack control*
a
good starting point
is
half rotation.
3.5
PLACEMENT OF THE 1178 LIMITER
IN
THE SIGNAL PATH
3.5.1
AFTER PREAMP
Small signals need to be amplified before they will cause proper
operation of the
1178 Limiter.
Only signal levels which
are above
the threshold of the limiter can cause
gain reduction.
For example:
In the 4:1
compression
ratio* the lowest threshold
is
-30
dB.
If
the signal applied to the input
is
about -20
dB*
then
the
1178
will provide
a
maximum
of
10
dB compression
with
the Input
Level control set to maximum.
The sensitivity
is
high enough
that
it
should not be difficult
to
obtain sufficient signal
level from most sources
which supply the audio
to
be processed
by the
1178.
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14
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Troubleshooting
