Orban Optimod-PC 1101, Operating Manual

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OPERATION ORBAN MODEL 1101
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
ASS
boost control (in the Equalization screen).
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
ATE
T
HR
(Gate Threshold) control is turned O
FF
, the DJ B
ASS
con-
trol is disabled.
AGC Bass Coupling control clamps the amount of dynamic bass boost (in units of
dB) that the AGC can provide.
The AGC processes audio in a master band for all audio above approximately 200 Hz
and a bass band for audio below approximately 200 Hz. The AGC Master and Bass
compressor sidechains operate without internal coupling. The gain reduction in the
B
ASS
audio path is either the output of the Bass compressor sidechain or the output
of the Master band sidechain. The
AGC B
ASS
C
OUPLING
control sets the switching
threshold. For example, if the
AGC B
ASS
C
OUPLING
control is set to 4 dB and the mas-
ter gain reduction is 10 dB, the bass gain reduction cannot decrease below 6 dB even
if the gain reduction signal from the Bass compressor sidechain is lower. However,
the audio path bass gain reduction can be larger than the master gain reduction
without limit. In the previous example, the bass gain reduction could be 25 dB
The normal setting of the AGC
B
ASS
C
OUPLING
control is 0 dB, which allows the AGC
bass band to correct excessive bass as necessary but does not permit it to provide a
dynamic bass boost.
Window Size determines the size of the floating “slow zone” window in the mas-
ter band of the AGC. (The Bass band is not windowed.)
The window works by slowing down changes in the AGC gain reduction that are
smaller than the
W
INDOW
S
IZE
. The window has 2:1 asymmetry around the current
AGC gain reduction. For example, if the
W
INDOW
S
IZE
is set to 4 dB, the window ex-
tends 4 dB in the release direction and 2 dB in the attack direction.
If the AGC needs to respond to a large change in its input level by making a gain
change that is larger than the window, then the AGC’s attack and release controls
determine the AGC’s response time. However, if the change in input level is smaller
than the window size, the
W
INDOW
R
ELEASE
control determines the attack and re-
lease times. This is usually much slower than the normal AGC time constants. This
prevents the AGC from building up density in material whose level is already well
controlled.
The previous explanation was somewhat simplified. In fact, the window has “soft
edges.” Instead of switching abruptly between time constants, the attack and re-
lease times morph smoothly between the setting of the
W
INDOW
R
ELEASE
control and
the setting of the AGC master release and attack controls.