Orban OPTIMOD-PC 1101 Operating Manual page 131

OPTIMOD-PC
•
Multiband Compression in either two or five bands, depending on the proc-
essing structure
•
Automatic Loudness Control using Orban's third-generation CBS Loudness
Controller™ algorithm
•
Low-IM Distortion Look-Ahead Limiting
STEREO
AGC
INPUT
CROSSOVER
ENHANCER
LF SHELVING EQ LF PEAKING EQ
EQUALIZER EQUALIZER
Stereo Enhancement: OPTIMOD-PC provides two different stereo enhancement
algorithms. The first is based on Orban's patented analog 222 Stereo Enhancer,
which increases the energy in the stereo difference signal (L–R) whenever a transient
is detected in the stereo sum signal (L+R). By operating only on transients, the 222
increases width, brightness, and punch without unnaturally increasing reverb (which
is usually predominantly in the L–R channel).
The second stereo enhancement algorithm is based on the well-known "Max" tech-
nique. This passes the L–R signal through a delay line and adds this decorrelated sig-
nal to the unenhanced L–R signal. Gating circuitry similar to that used in the "222-
style" algorithm prevents over-enhancement and undesired enhancement on slight-
ly unbalanced mono material.
Use stereo enhancement with care if you are driving a low bitrate codec. At low bi-
trates, these codecs use various parametric techniques for encoding the spatial at-
tributes of the sound field. Stereo enhancement can unnecessarily stress this encod-
ing process.
MASTER
>150Hz
COMPRESSOR
COUPLING
BASS
<150Hz
COMPRESSOR
MF PEAKING EQ HF PEAKING EQ
EQUALIZER EQUALIZER
Figure 3-2: Simplified OPTIMOD-PC Digital Signal Processing Diagram
>6kHz
MULTIBAND
HIGH
CROSSOVER
FREQUENCY
ENHANCER
1800-6000Hz
520-1800Hz
100-520Hz
XOVER IN
<100Hz
or
<200Hz
>200Hz
2-BAND
COUPLING
CROSSOVER
<200Hz
OPERATION
LOUDNESS
METER
COMPRESSOR
COMPRESSOR
LOUDNESS
5B
COMPRESSOR
CONTROLLER
2B
COMPRESSOR
COMPRESSOR
+ EMBEDDED
CLIPPER
COUPLING OUTPUT MIX
CONTROLS CONTROLS
MASTER
COMPRESSOR
BASS
COMPRESSOR
3-11
AGC
OUT
LOW IM MAIN
LOOK-AHEAD
LIMITER OUT
"PROCESSED WITHOUT LIMITING" OUT