Optimod-Surround 8685 V1.0 Operating Manual - Orban

OPTIMOD SURROUND PROCESSOR INSTALLATION 2-11
B) Set the Surround External AGC mode.
• Set the field to YES if you have an external AGC installed at your studio
feeding the studio-to-transmitter link. This setting appropriately defeats
the 8685’s AGC for all presets.
• If you do not have an external AGC installed, set the field to NO; this setting
allows the selected preset to determine the 8685 AGC status.
C) Set the 2.0 External AGC mode (see above for choices).
7. Set surround and 2.0 reference levels.
The Reference Level screen allows you to match the 8685’s processing to the
normal operating level expected at the 8685’s input so the 8685’s AGC can operate
in the range for which it was designed. If you know the reference VU or PPM
level (sometimes known as “lineup level”) that will be presented to the 8685, set
the SURROUND REFERENCE LEVEL to this level.
It is wise to verify your setting with the steps below, which also allow you to set
the reference level controls when you do not know the reference VU or PPM
level that will be presented to the 8685.
A) Feed normal program material to the 8685.
Play program material from your studio, peaking at normal program levels
(typically 0VU if your console uses VU meters).
B) LOCATE to the Reference Levels screen (SYSTEM SETUP > QUICK SETUP 6).
C) Adjust the SURROUND REFERENCE LEVEL so that the surround AGC meter reads
an average of 10 dB gain reduction.
[−40 to –10 dBFS (VU), or –33 to –3 dBFS (PPM)] in 0.5 dB steps.]
The DIGITAL REFERENCE LEVEL VU and PPM settings track each other with
an offset of 8 dB. This compensates for the typical indications with program
material of a VU meter versus the higher indications on a PPM.
D) If you will be using the 2.0 processors, adjust the 2.0 REFERENCE LEVEL so that
the 2.0 AGC meter reads an average of 10 dB gain reduction.
8. Set the surround and 2.0 output feeds and sample rates.
A) LOCATE to the Output Configuration screen (SYSTEM SETUP > QUICK SETUP 7).
B) Choose one of the following to feed the hardware outputs assigned to the
surround audio processing:
• MB+LIMIT (stereo enhancement, equalization, AGC, two-band or 5-Band
compression, loudness control, and look-ahead peak limiting). This setting
is correct for most applications, including driving a digital television transmitter.
It fully supports Dialnorm.
The three settings below do not support Dialnorm automatically: