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OPTIMOD-PC
•
Adjust the AGC (with the AGC D
AGC action, and then fine-tune the compression and clipping with the Five-Band
structure's controls.
AGC Gate ("AGC Gate Threshold") control determines the lowest input level that
will be recognized as program by OPTIMOD-PC; lower levels are considered to be
noise or background sounds and cause the AGC or multiband compressor to gate,
effectively freezing gain to prevent noise breathing.
In sound for picture, the setting of the gate threshold controls are quite critical if
you want the processing to be undetectable to the audience. If this control is set too
low, then OPTIMOD-PC will pump up quiet sounds such as ambience and underscor-
ing to unnaturally high levels.
There are two independent silence-gating circuits in OPTIMOD-PC. The first affects
the AGC and the second affects the multiband compressor (2-band or 5-band).
Each has its own threshold control.
In the five-band structure, the multiband silence gate causes the gain reduction in
bands 2 and 3 of the five-band compressor to move quickly to the average gain re-
duction occurring in those bands when the gate first turns on. This prevents obvious
midrange coloration under gated conditions, because bands 2 and 3 have the same
gain.
The multiband gate also independently freezes the gain of the two highest fre-
quency bands (forcing the gain of the highest frequency band to be identical to its
lower neighbor), and independently sets the gain of the lowest frequency band ac-
cording to the setting of the DJ B
Thus, without introducing obvious coloration, the gating smoothly preserves the
average overall frequency response "tilt" of the multiband compressor, broadly
maintaining the "automatic equalization" curve it generates for a given piece of
program material.
If the MB G
control is disabled.
AGC Bass Coupling control sets the balance provided in the AGC between bass
and the rest of the frequency spectrum.
The AGC processes audio in a Master band for all audio above approximately 200Hz
and a Bass band for audio below approximately 200Hz. The AGC B C
termines how closely the spectral balance of material below 200Hz matches that of
the program material above 200Hz.
Settings toward 100% (wideband) make the output sound most like the input. Be-
cause setting the AGC B C
most accurate frequency balance will often be obtained with this control between
70% and 90%. The optimum setting depends on the amount of gain reduction ap-
plied and on the AGC release time. Usually, you will adjust the AGC B C
until the Master AGC and Bass AGC Gain Reduction meters track as closely as possi-
control) to produce the desired amount of
RIVE
boost control (in the Equalization screen).
ASS
(Gate Threshold) control is turned O
T
ATE
HR
control at 100% will sometimes cause bass loss, the
PL
OPERATION
, the DJ B
FF
ASS
control de-
PL
control
PL
3-35
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