Orban OPTIMOD-FM 8600Si, Operating Manual

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OPTIMOD-FM DIGITAL OPERATION
3-53
The
L
ESS
-M
ORE control affects only the input drive, and you can use it to set a nomi-
nal limiting level different from 0 dB or 5 dB.
The Protection presets have the same Intermediate and Advanced Modify controls
available as the Two-Band structure.
Setting Up the Two-Band Structure for Classical Music
To set up the Two-Band structure, recall preset
CLASSICAL-2 BAND
or
CLASSICAL-
2B+AGC
.
These are the only two-band presets (other than the
PROTECTION
presets).
Classical music is traditionally broadcast with a wide dynamic range. However, with
many recordings and live performances, the dynamic range is so great that the quiet
passages disappear into the noise on most car, portable, and table radios. Conse-
quently, the listener either hears nothing, or must turn up the volume control to
hear all the music. Then, when the music gets loud, the radio blasts and distorts,
making listening unpleasant.
The Two-Band structure is well suited for classical formats during daytime hours
when most people in the audience are likely to be listening in autos or to be using
the station for background music. This audience is best served when the dynamic
range of the program material is reduced by 10-15 dB so that quiet passages in the
music never fade into inaudibility under these less-favorable listening conditions.
OPTIMOD-FM controls the level of the music in ways that are, for all practical pur-
poses, inaudible to the listener. Low-level passages are increased in level by up to 10
dB, while the dynamics of crescendos are maintained.
The
CLASSICAL-2 BAND
preset is a two-band preset with the AGC turned off. It uses
considerable bass coupling to preserve the spectral balance of the input as well as
possible. Its
L
ESS
-M
ORE
control primarily affects the amount of compression, rather
than maximum loudness. It sounds essentially identical to the Protection structure.
CLASSICAL-2B+AGC
uses the AGC set for 2:1 compression ratio. Because of the
AGC, it affects more of the total dynamic range of the recording that does the
CLASSICAL-2 BAND
preset. However, the AGC provides extremely smooth and un-
obtrusive compression because of the gentle ratio and window gating. In this preset,
the Two-Band compressor is used very lightly with a fast release time as a peak lim-
iter. The AGC does almost of the compression.
During the evening hours when the audience is more likely to listen critically, a clas-
sical station may wish to switch to a custom preset (derived from the
CLASSICAL-2
BAND
preset) that performs less gain reduction. You can create such a preset by
modifying the
CLASSICAL-2 BAND
preset with the
L
ESS
-M
ORE
control — turn it
down to taste.
There are also two five-band classical presets. The
CLASSICAL-5 BAND
preset uses the
five-band structure with AGC defeated. It uses substantial interband coupling to re-
tain much of the frequency balance of the original source, but is capable of some-