Orban OPTIMOD-FM 8700, Operating Manual

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OPERATION ORBAN MODEL 8700i
troducing 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.
Note: If the
M
ULTIBAND
G
ATE
T
HRESH
(Gate Threshold) control is turned
O
FF
, the DJ B
ASS
control (in the Equalization screen) 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.
Advanced AGC Controls
The following AGC controls are found only in the Advanced Modify screen.
AGC Max Delta GR determines the maximum gain difference permitted between the
two channels of the AGC. Set it to “0” for perfect stereo coupling.
This control works the same regardless of whether the AGC operates in
left/right or sum / difference
M
ATRIX
modes, in both cases controlling the
maximum gain difference between the “channels.” Depending on the
M
ATRIX
mode setting, the “channels” will handle left and right signals or
will handle sum and difference signals. When the AGC operates in sum /
difference
M
ATRIX
mode, this control determines the maximum amount
of width change in the stereo sound field.
Window Size determines the size of the floating “slow zone” window in the master
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-