Wideband AGC (WB)
This is the first processing section within
the Omnia, so the controls in this section
affect the overall signal, its density, and
hence affect every other processing section
following it. The job of the Wideband AGC
is to erase long-term audio level
fluctuations, while doing so in a very
unobtrusive manner.
Wideband AGC Submenu
The
AGC Drive
control is calibrated between –12dB and +6dB, and adjusts the signal level into the Wideband AGC.
This control should be adjusted to net approximately 12dB of gain reduction with typical programming. Too little
gain reduction can defeat the “leveling” function of the Wideband AGC. Too much gain reduction has little
additional benefit. Nominal gain reduction values for the Wideband AGC are between 10 and 15dB.
The
Attack
and
Release
controls set the Wideband AGC time constants in relative terms using the numbers 0 - 7.
Lower numbers are slower time constants, while higher numbers are faster time constants. Because the time
constants are program-dependent, calibrating these controls in absolute time values (ms/dB) would be useless—
therefore we use relative numbers. Use a
higher
number if you want “faster” attack and release, and a
lower
number
for “slower” attack and release. A special algorithm within the Wideband AGC Attack time circuit prevents the loss
of Wideband AGC gain reduction when the Attack time control is operated at extremely slow values.
The
Make-Up Gain
control sets the amount of gain to be filled in during quieter, softer program passages. The range
is
OFF
to
7
. This function is also program dependent, and it interacts somewhat with the main Attack and Release
time constants. As the attack/release times are modified, the system also scales the
Make-Up Gain
time constants.
Use
less
makeup gain for processing more faithful to the source material; use
more
makeup gain for greater loudness
and “density.”
The
Gate Thresh
old control sets the level at which gating of the AGC occurs, “freezing” the gain during short
pauses. Correct adjustment of this control helps to minimize “pumping”, and the increase of background noise
during pauses in programming. The control range is
OFF
to
7
.
There are two RTP (Return to Platform) parameters,
RTP Speed
and
RTP Level,
which determine what happens to
the AGC gain when the
Gate Thresh
old is reached and audio is gated. With the
RTP Level
set to -
5
, -
10
or -
15
dB
of gain reduction, the gain will return to that pre-defined level when gated. How quickly the target gain reduction
level is reached, is set by the remaining
RTP Speed
settings (Slow, Medium or Fast). If no RTP gain
reduction
is
desired, use the
RTP Speed
setting
Freeze
.
Omnia-6ex Use and Operation Manual – V: 1.10
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