Orban OPTIMOD-FM 8500S Operating Manual page 198

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OPERATION
gated. (It gates whenever the input level to the structure is below the threshold of
gating.)
The total amount of gain reduction in the Five-Band structure is the sum of the gain
reduction in the AGC and the gain reduction in the multiband compressor. The total
system gain reduction determines how much the loudness of quiet passages will be
increased (and, therefore, how consistent overall loudness will be). It is determined
by the setting of the AGC D
or PPM is peaked, and by the setting of the MB D
Master AGC Release control provides an adjustable range from 0.5 dB / second
(slow) to 20 dB / second (fast). The increase in density caused by setting the AGC
R control to fast settings sounds different from the increase in density caused
ELEASE
by setting the Multiband's MB R
off to produce different effects.
Unless it is purposely speeded-up (with the MB R
control (AGC) that occurs in the AGC prior to the multiband compressor makes audio
levels more consistent without significantly altering texture. Then the multiband
compression and associated multiband clipper audibly change the density of the
sound and dynamically re-equalize it as necessary (booming bass is tightened; weak,
thin bass is brought up; highs are always present and consistent in level).
The various combinations of AGC and compression offer great flexibility:
•
Light AGC + light compression yields a wide sense of dynamics, with a small
amount of automatic re-equalization.
•
Moderate AGC + light compression produces an open, natural quality with
automatic re-equalization and increased consistency of frequency balance.
•
Moderate AGC + moderate compression gives a more dense sound, particularly
as the release time of the multiband compressor is sped up.
•
Moderate AGC + heavy compression (particularly with a
time) results in a "wall of sound" effect, which may cause listener fatigue.
Adjust the AGC (with the AGC D
action and then fine-tune the compression and clipping with the Five-Band struc-
ture's controls.
AGC Gate Thresh (Threshold) control determines the lowest input level that will
be recognized as program by OPTIMOD-FM; lower levels are considered to be noise
or background sounds and cause the AGC or multiband compressor to gate, effec-
tively freezing gain to prevent noise breathing.
There are two independent gating circuits in the 8500S. The first affects the AGC
and the second affects the multiband compressor. Each has its own threshold con-
trol.
control, by the level at which the console VU meter
RIVE
RIVE
control to F
ELEASE
ELEASE
control) to produce the desired amount of AGC
RIVE
ORBAN MODEL 8500S
(compressor) control.
, and you can trade the two
AST
control), the automatic gain
multiband release
FAST