Orban OPTIMOD 6200, Operating Manual

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OPTIMOD OPERATION
3-21
For television, recall a TV Two-Band preset that matches the program material. (See
page 3-11).
Gain Reduction Metering
Unlike the metering on some processors, when any OPTIMOD-DAB gain reduction me-
ter indicates full-scale (at its bottom), it means that its associated compressor has run out
of gain reduction range, that the circuitry is being overloaded, and that various nasti-
nesses are likely to commence.
Because the compressor in the Two-Band structure has 25dB of gain reduction range, the
meter should never come close to 25dB gain reduction if OPTIMOD-DAB has been set
up for a sane amount of gain reduction under ordinary program conditions.
But be aware of the different peak factors on voice and music — if voice and music are
peaked identically on a VU meter, voice may cause up to 10dB more peak gain reduction
than does music! (A PPM will indicate relative peak levels much more accurately.)
Using the Two-Band Structure for Classical Music
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 pas-
sages disappear into the noise on most car, portable, and table radios. Consequently, 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 the listening rather
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 pro-
gram material is compressed 10-15dB so that quiet passages in the music never fade into
inaudibility under these less-favorable listening conditions. OPTIMOD-DAB controls
the level of the music in ways that are, for all practical purposes, inaudible to the lis-
tener. Low-level passages are increased in level by up to 10dB, while the dynamics of
crescendos are maintained.
The
2B CLASSICAL
preset is a two-band preset with the AGC turned
off
. It uses consid-
erable bass coupling to preserve the spectral balance of the input as well as possible. Its
LESS-MORE
control primarily affects the amount of compression, rather than maximum
loudness. It sounds essentially identical to the Protection Limiter structure.
During the evening hours when the audience is more likely to listen critically, a classical
station may wish to switch to a custom preset (derived from the
2B CLASSICAL
preset)
that performs less gain reduction. You can create such a preset by modifying the
2B
CLASSICAL
preset with the
LESS-MORE
control — turn it down to taste.
Internally, the Protection Limiter structure is the same as the Two-Band
structure, but the AGC is turned off and its presets have been tuned to pro-