Orban 8300J Operating Manual Download

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OPTIMOD-FM DIGITAL

OPERATION

3-29

noise or background sounds and cause the AGC or multiband compressor to gate,
effectively freezing gain to prevent noise breathing.

There are two independent gating circuits in the 8300. The first affects the

AGC

and

the second affects the

multiband compressor

. Each has its own threshold control.

The multiband compressor gate causes the gain reduction in bands 2 and 3 of the
multiband compressor to quickly move to the average gain reduction occurring in
those bands when the gate first turns on. This prevents obvious midrange coloration
under gated conditions, because bands 2 and 3 have the same gain.

The gate also independently freezes the gain of the two highest frequency 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 according
to the setting of the

ASS

boost control (in the Equalization screen). Thus, with-

out 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 mate-
rial.

If the

ATE

(Gate Threshold) control is turned

, the

ASS

control is disabled.

AGC B CPL

(“AGC Bass Coupling”) control clamps the amount of dynamic bass

boost (in units of dB) that the AGC can provide. (In V2.0, the unit of measure was
percent.)

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. Starting with V2.1 software,
the AGC Master and Bass compressor sidechains operate without internal coupling.
The gain reduction in the Bass audio path is either the output of the Bass compres-
sor sidechain or the output of the Master band sidechain. The

AGC

ASS

OUPLING

control sets the switching threshold. For example, if the

AGC

ASS

OUPLING

control

is set to 4 dB and the master 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 re-
duction could be 25 dB

The normal setting of the AGC

ASS

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.

Note that the operation of this control was changed in 8300 V2.1 software to work
as explained above. You may have to tweak this control to achieve the same bass
balance that you had previously with V2.0 software.

AGC METR (“AGC Meter Display”)

determines what signal the front-panel AGC

meter displays.

ASTER

displays the gain reduction of the Master (above-200 Hz)

band.

ELTA

displays the difference between the gain reduction in the Master and

Bass bands. Full-scale is 25 dB gain reduction.