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OPERATION ORBAN MODEL 8685
• TV AGC+LC+DS uses the five-band structure with all multiband compressors ex-
cept for LFE and B5 turned off. B5 is configured as a de-esser, which, depending
on the strictness of a given “wideband-only” edit, may be an acceptable use of
frequency-selective gain reduction. (In our experience, there is a significant
amount of television material that has not been adequately de-essed in produc-
tion and thus requires additional de-essing from the on-air processing.)
This preset sounds better than TV AGC+LC because the loudness controller does
not have to de-ess, which it does by using wideband gain reduction. Hence, it is
less likely to audibly duck material having heavy “esses.”
Protection and Studio AGC Presets
AGC+ FLAT LIMITER: This preset allows the 8685 to serve as a studio AGC, substitut-
ing for the AGC in an Optimod at a radio or television transmitter and providing
protection limiting for the STL that links the output of the 8685 to the input of the
Optimod at the transmitter. It uses the look-ahead limiter to prevent overloading
the STL on peaks.
This preset is tuned so that it does not normally trigger gain reduction in the 8685’s
five-band compressor — the Optimod at the transmitter should be the processor
that performs this multiband compression.
LOOK-AHEAD LIMITER: The L
OOK-AHEAD LIMITER preset is a Two-Band preset that
turns off the stereo enhancer, AGC, equalizer, and two-band compressor so that you
can use the processing as a fast look-ahead protection limiter.
This preset’s L
ESS-MORE control is set to 1.0. For most program material, LESS-MORE
= 1.0 will produce no look-ahead limiter gain reduction.
• In the surround processing channel, when L
ESS-MORE = 1.0 and the Lf and Rf
channels are both driven, the threshold of the look-ahead limiter is 16 dB above
reference level.
• In the 2.0 processing channel, when L
ESS-MORE = 1.0 and the Lst and Rst chan-
nels are both driven, the threshold of the look-ahead limiter is 18 dB above ref-
erence level.
This assumes that the 8685’s SURROUND REF LEVEL and 2.0 REF LEVEL con-
trols have been adjusted to produce 10 dB of AGC Master band gain re-
duction in the surround and 2.0 AGCs respectively when the R
OCK-
G
ENERAL preset is active and the 8685’s Lf, Rf, Lst, and Rst inputs are
driven by a 400 Hz tone at your facility’s reference level. This level is typi-
cally either –18 dBfs or –20 dBfs, depending on which standard you have
adopted.
To produce look-ahead limiter gain reduction, turn up the LESS-MORE control. Each
step of the L
ESS-MORE control increases the drive level to the look-ahead limiter by
1 dB and increases the input/output gain by 1 dB for signals below the limiter
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