Orban OPTIMOD 8400 Operating Manual page 140

3-32
OPERATION
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 8400. 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 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 under gated con-
ditions, 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 inde-
pendently sets the gain of the lowest frequency band according to the setting of the
boost control (in the Equalization screen). Thus, without introducing obvious col-
Bass
oration, the gating smoothly preserves the average overall frequency response "tilt" of the
multiband compressor, broadly maintaining the "automatic equalization" curve it gener-
ates for a given piece of program material.
Note: If the
the
DJ Bass
AGC Bass Coupling control sets the balance provided in the AGC between bass and the
rest of the frequency spectrum.
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
determines how closely the on-air balance of material below 200 Hz matches that of the
program material above 200 Hz.
Settings toward 100% (wideband) make the output sound most like the input. Because
setting the
AGC Bass Coupling
accurate frequency balance will often be obtained with this control between 70% and
90%. The optimal setting depends on the amount of gain reduction applied and on the
AGC release time. Usually, you will adjust the
ter AGC and Bass AGC Gain Reduction meters track as closely as possible unless you
want the AGC to provide some gentle automatic re-equalization of the input material.
With the
Master AGC Release
control toward 0% (independent) will produce a sound that is very open, natural,
pling
and non-fatiguing, even with large amounts of gain reduction. Such settings will provide
a bass boost on some program material that lacks bass.
With fast release times, settings of the
not sound good. Instead, set the
This combination of fast release and independent operation of the bands provides the
maximum loudness and density on small radios achievable by the Five-Band structure.
(Gate Threshold) control is turned
Multiband Gate Thresh
control (in the Equalization screen) is disabled.
control at 100% will sometimes cause bass loss, the most
AGC Bass Coupling
control set to 2 dB/second, setting the
AGC Bass Coupling
AGC Bass Coupling
ORBAN Model 8400
AGC Bass Coupling
control until the Mas-
AGC Bass Cou-
toward 100% (wideband) do
control toward 0% (independent).
DJ
,
Off
control