Orban OPTIMOD 6300 Operating Manual page 184

3-42
OPERATION
The various combinations of AGC and compression offer great flexibility:

Light AGC + light compression yields a wide sense of dynamics, with a small
amount of automatic re-equalization.

Moderate AGC + light compression produces an open, natural quality with
automatic re-equalization and increased consistency of frequency balance.

Moderate AGC + moderate compression gives a more dense sound, particularly
as the release time of the multiband compressor is sped up.

Moderate AGC + heavy compression (particularly with a FAST multiband release
time) results in a "wall of sound" effect, which may cause listener fatigue.

Adjust the AGC (with the AGC D
AGC action, and then fine-tune the compression with the 5-band structure's con-
trols.
AGC GATE ("AGC Gate Threshold") control determines the lowest input level that
will be recognized as program by OPTIMOD 6300; lower levels are considered to be
noise or background sounds and cause the AGC or multiband compressor to gate,
effectively freezing gain to prevent noise breathing.
In sound for picture, the setting of the gate threshold controls are quite critical if
you want the processing to be undetectable to the audience. If this control is set too
low, then the 6300 will pump up quiet sounds such as ambience and underscoring to
unnaturally high levels.
There are two independent silence-gating circuits in the 6300. The first affects the
AGC and the second affects the multiband compressor. Each has its own thresh-
old control.
AGC Idle Gain on page 3-44 explains how the AGC gate's no-signal gain is deter-
mined.
The multiband silence gate causes the gain reduction in bands 2 and 3 of the multi-
band compressor to move quickly to the average gain reduction occurring in those
bands when the gate first turns on. This prevents obvious midrange coloration un-
der gated conditions, because bands 2 and 3 have the same gain.
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
Thus, without introducing obvious coloration, the gating smoothly preserves the av-
erage overall frequency response "tilt" of the multiband compressor, broadly main-
taining the "automatic equalization" curve it generates for a given piece of pro-
gram material.
If the MB G
control is disabled.
RIVE control) to produce the desired amount of
boost control (in the Equalization screen).
ASS
T (Gate Threshold) control is turned O
ATE HR
ORBAN MODEL 6300
, the DJ B
FF ASS