Orban Optimod-FM 8300 Operating Manual page 125

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OPTIMOD-FM DIGITAL OPERATION
prevents the AGC from applying additional, audible gain control to material that is
already well controlled. It also lets you run the AGC with fast release times without
adding excessive density to material that is already dense.
The AGC contains a compression ratio control that allows you to vary to ratio be-
tween 2:1 and essentially :1. Lower ratios can make gain riding subtler on critical
formats like classical and jazz.
The AGC has its own silence-gating detector whose threshold can be set independ-
ently of the silence gating applied to the multiband compressor.
Equalization: The 8300 has steep-slope bass shelving equalizer and three bands of
fully parametric bell-shaped EQ.
You can set the slope of the bass shelving EQ to 6, 12, or 18 dB/octave and adjust the
shelving frequency.
The 8300's bass, midrange, and high frequency parametric equalizers have curves
that were modeled on the curves of Orban's classic analog parametrics (like the
622B), using a sophisticated, proprietary optimization program. The curves are
matched to better than 0.15 dB. This means that their sound is very close to the
sound of an Orban analog parametric. They also use very high quality filter algo-
rithms to ensure low noise and distortion.
The 8300 HF Enhancer is a program-controlled HF shelving equalizer that was origi-
nally introduced in Orban's 2200 OPTIMOD-FM. It intelligently and continuously ana-
lyzes the ratio between broadband and HF energy in the input program material,
and can equalize excessively dull material without over-enhancing bright material. It
interacts synergistically with the five-band compressor to produce sound that is
bright and present without being excessively shrill.
Multiband Compression: The multiband compressor can be operated in five-band
or two-band mode. In addition to using a special high-frequency limiter, we control
high frequencies with distortion-canceled clipping. The clipper in the 8300 operates
at 256 kHz-sample rate and is full anti-aliased.
Ordinarily, the gain reduction in band 5 follows the gain reduction in band 4 (as de-
termined by the setting of the B4>B5 C control); these bands are only inde-
OUPLE
pendent from the viewpoint of the downward expander and multiband clippers.
However, a high frequency limiter causes additional gain reduction in band 5 when
band 5 multiband clipping alone would be insufficient to prevent HF distortion. The
HF limiter uses a sophisticated analysis of the signal conditions in the 8300's clipping
system to do this.
A clipper, embedded in the crossover, protects bands 1 and 2 from transient over-
shoot. This clipper has a shape control, allowing you to vary the "knee" of its in-
put/output transfer curve from hard (0) to soft (10).
Digital Radio Processing: After multiband compression, the signal path splits into
two branches. The FM analog processing branch applies high frequency limiting and
clipping, while the digital radio branch applies look-ahead limiting to the audio. To