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OPTIMOD-PC
Never lose sight of the fact that, while the listener can easily control loudness, he or
she cannot make a distorted signal clean again. If such excessive processing is per-
mitted to audibly degrade the sound of the original program material, the signal is
irrevocably contaminated and the original quality can never be recovered.
Sound for Picture Applications: Controlling Dynamic Range
The most crucial commandment in sound for picture is this: dialog must always be
intelligible. Sound for picture is usually heard under less-than-ideal conditions and
its dynamic range must be controlled accordingly. Apartment-dwellers must set their
volume controls to avoid disturbing neighbors or even other members of the family.
At the quiet side, intelligibility of dialog is often impacted by environmental noise
such as children playing or a dishwasher going in the kitchen. When one considers
that the hearing acuity of a significant portion of the audience is somewhat im-
paired compared to that of a healthy 20-year-old, one concludes that the dynamic
range of dialog must not exceed 15dB if it is to be intelligible to 99% of viewers un-
der common domestic viewing conditions. Feature-film dynamic range is inappropri-
ate for home viewing (except in dedicated home theaters) and the dynamic range of
a significant portion of video source material must be compressed to best serve the
audience. The challenge (which Optimod-PC effectively meets) is to compress dy-
namic range unobtrusively.
OPTIMOD-PC can be adjusted so that the output sounds as close as possible to the
input at all times (using the Two-Band Protection Limiter preset), or so that it sounds
open but more uniform in frequency balance than the input (using the Two-Band
structure or running the Five-band structure with slow release time), or so that it
sounds dense, quite squashed, and very loud (using the Five-band structure with
faster release times).
The dense, loud setup is almost always inappropriate for sound for picture unless
the station has unusual programming and goals. Most stations will want to use sim-
ple protection processing when broadcasting material that has been carefully pro-
duced by people cognizant of the dynamic range limitations of sound for picture.
For most other program material, the Two-Band or Slow Five-Band structures are
appropriate.
The subjective setup controls on OPTIMOD-PC give you the flexibility to adapt the
processing to individual program segments. In most cases, your goal should be to
choose the type of processing that best optimizes dynamic range while controlling
the loudness of the loudest sounds so that they are not irritating and are consistent
with the loudness of other stations or sources.
Protection Limiting
OPTIMOD-PC has an advanced look-ahead limiter that is competitive with the best
mastering peak limiters. The L
PC as a mastering-style look-ahead limiter.
-A
L
preset allows you to use OPTIMOD-
OOK
HEAD
IMITER
3-7
OPERATION
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