Optimod-Surround 8685 V1.0 Operating Manual - Orban

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OPERATION ORBAN MODEL 8685
lease times morph smoothly between the setting of the WINDOW RELEASE control and
the setting of the AGC master release and attack controls.
The most useful range of the AGC WINDOW SIZE is 3 to 6 dB.
AGC Window Release (see AGC WINDOW SIZE above.)
AGC Ratio determines the compression ratio of the AGC. The compression ratio is
the ratio between the change in input level and the resulting change in output
level, both measured in units of dB.
The 8685 compressor can be operated at a compression ratio as low as 2:1. This can
add a sense of dynamic range and is mostly useful for subtle fine arts formats like
classical and jazz.
AGC Bass Threshold determines the compression threshold of the bass band in the
AGC. It can be used to set the target spectral balance of the AGC.
As the AGC BASS COUPLING control is moved towards 0 dB, the AGC BASS THRESHOLD
control affects the sound less and less.
The interaction between the AGC BASS THRESHOLD control and the AGC BASS
COUPLING control is a bit complex, so we recommend leaving the AGC BASS
THRESHOLD control at its factory setting unless you have a good reason for readjusting
it.
AGC Idle Gain. The “idle gain” is the target gain of the AGC when the silence gate
is active. Whenever the silence gate turns on, the gain of the AGC slowly moves towards
the idle gain.
The idle gain is primarily determined by the AGC DRIVE setting—a setting of 10 dB
will produce an idle gain of –10 dB (i.e., 10 dB of gain reduction) when the AGC IDLE
GAIN control = 0 dB. However, sometimes you may not want the idle gain to be the
same as the AGC DRIVE setting. The AGC IDLE GAIN control allows you to add or subtract
gain from the idle gain setting determined by the AGC DRIVE setting.
You might want to do this if you make a custom preset that otherwise causes the
gain to increase or decrease unnaturally when the AGC is gated. For example, to
make the idle gain track the setting of the AGC DRIVE control, set the AGC IDLE GAIN
control to zero. To make the idle gain 2 dB lower than the setting of the AGC DRIVE
control, set the AGC IDLE GAIN control to –2.
AGC Bass Attack sets the attack time of the AGC bass compressor (below 200Hz).
The calibration is approximate.
AGC Master Attack sets the attack time of the AGC master compressor (above
200Hz). The calibration is approximate.
AGC Bass Release sets the release time of the AGC bass compressor.
AGC Crossover allows you to choose ALLPASS, LINEAR or LINEARNODELAY modes.