Some Audio Processing Concepts - Orban 8182A Operating Manual

Understanding
More About Audio
Processing
If
you
are using one of
the
sets of
recommended
control
settings
given
in
Fig. 3-3, there
is
no need
to
read
this section.
Read
this
section only
if
you
really
want
to
understand
the
operating
controls
in detail.
The
controls
on
the
8182A
and
8182A/SG
give you
the flexibility to
customize your
station's
sound. But,
as
with any audio processing system, proper adjustment of
these
controls consists of balancing
the trade-offs
between
consistency, loudness, density,
brightness,
and
audible
distortion.
The
following provides the information you need
to
understand
the functions
and
interactions
of
the audio processing
controls.
We
recommend
starting
with
one of
the
sets
of
recommended
settings,
and
then
spending
some
time
listening
critically to
your
on-air sound. Listen
to
a
wide
range
of program
material typical
of your
station,
and
listen
on
a variety
of
television
receivers (not
just
on
your
control
room
monitor
loudspeakers).
Some
audio
processing concepts.
Compression
reduces
the difference in level
between
the
soft
and loud
sounds,
re-
sulting in a subjective increase
in the
loudness of
soft
sounds and
a greater overall
consistency
in
perceived loudness
levels.
Limiting
increases audio density. Increasing density
can
result in greater consistency
between program
segments, but can
also result in
an unattractive "busier",
"flatter",
or "denser" sound.
It is
important
to
be aware of
the
many
negative subjective
side
effects
of
excessive density
when
setting
controls
which
affect the density of
the
processed sound.
Clipping
sharp
peaks does not produce any
audible
side effects
when
done moder-
ately.
Excessive
clipping,
however,
will
be perceived
as audible
distortion.
Consistent subjective loudness
is
achieved
by
controlling the
average
level
of
the
audio according
to
an
model
of
how
the
human
ear
and
brain perceive loudness. In the
8182A,
this
is
realized through the
complex
circuitry
of
the
loudness
controller.
The
carefully
designed dual-band compressor
in
the 8
182
A
also helps achieve consistent
loudness.
Gating
for
unobtrusive processing.
Proper
setting
of
the
GATE threshold
control
is
the
key
to
achieving unobtrusive pro-
cessing.
Inappropriate
settings
of
this
control are
more
likely to
cause complaints
from viewers and producers about "excessive compression" than
are incorrect settings
of any
other control.
The
gating function prevents unnatural level increases
of low-level
program
material.
Many
TV
audio feeds
(like
ENG
and
optical
soundtracks
on
film)
have poor
signal-
to-noise
ratios.
Such
material will suffer if
the level
background
noise
is
audibly
increased
by
the processor.
It
would
also
be
wrong
to pull
up
underscoring or other
background
to the level
of dialog during pauses
in
the dialog.
5-7