Orban Optimod-FM 8300 Operating Manual page 167

OPTIMOD-FM DIGITAL
nouncers and guests consistent, pulls low-grade telephone calls out of
the mud, and keeps a proper balance between voice and commercials.
Voice is the most difficult audio to process, but these settings result in a
favorable trade-off between consistency, presence, and distortion.
The Factory Presets for this sound are quite different from the other
three release time settings. The amount of gain reduction in the multi-
band compressor is substantially lower (so that it operates more like a
limiter than like a compressor), and the release time of the gain-riding
AGC is speeded up (so that it provides compression and some increase of
density). We made these trade-offs to prevent excessive build-up of den-
sity.
It is possible to experiment with this sound for music-oriented program-
ming as well. However, even with these settings, your sound is getting
farther away from the balance and texture of the input. We think that
this is as far as processing can go without causing unacceptable listener
fatigue. However, this sound may be quite useful for stations that are or-
dinarily heard very softly in the background because it improves intelligi-
bility under these quiet listening conditions. Stations that are ordinarily
played louder will probably prefer one of the slower release times, where
the multiband compressor takes more gain reduction and where the AGC
is operated slowly for gentle gain riding only. These slower sounds are
less consistent than those produced by the FAST setting. Using SLOW
preserves more of the source's frequency balance, making the sound less
dense and fatiguing when the radio is played loudly.
Bx THR ("Band x Compression Threshold") controls set the compression threshold in
each band, in units of dB below the final clipper threshold. We recommend making
small changes around the factory settings to avoid changing the range over which
the MB CLIPPING control operates. These controls will affect the spectral balance of
the processing above threshold, but are also risky because they can strongly affect
the amount of distortion produced by the back-end clipping system.
MB GATE ("Multiband Gate Threshold") control determines the lowest input level
that will be recognized as program by OPTIMOD-FM; 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.
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 move quickly 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 DJ B
out introducing obvious coloration, the gating smoothly preserves the average
boost control (in the Equalization screen). Thus, with-
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OPERATION