The Two-Band Structure - Orban Optimod-PC 1101 Operating Manual

3-40
OPERATION

The Two-Band Structure

low B
C T
ASS LIP HRESH
"7.6." See Figure 3-3 on page 3-39.
Final Limit Drive control adjusts the level of the audio driving the low-IM look-
ahead limiter that OPTIMOD-PC uses to control fast peaks, thereby adjusting the
peak-to-average ratio of the processed audio. The F
determines the loudness/distortion trade-off.
Turning up the F
L
INAL
ing the peak-to-average ratio, and increasing the loudness on the air. When the
amount of limiting is increased, the audible intermodulation distortion caused by
limiting increases, even though special algorithms minimize the increase compared
to less sophisticated designs. Lower settings reduce loudness, of course, but result in
a cleaner sound.
When you use OPTIMOD-PC in a preemphasized mode (step 5 on page 2-23), this
inserts a frequency-dependent high frequency boost before the look-ahead limiter.
This boost can be as large as 20 dB at 20 kHz. When using preemphasis, you must
turn down the F
L
INAL
ing audible gain pumping.
You may find it illuminating to recall several Factory Presets, adjust L
to several points in its range, and then open the Full Control screen
M
ORE
to examine the trade-offs between the release time and F
made by the factory programmers. However, note that all Factory Presets
were created to complement F
must turn down the F
Distortion Control Adjustments
Name
Bass Clip Threshold
Speech Bass Clip Threshold
Bass Clip Shape
Final Limit Drive
The Two-Band structure consists of a stereo enhancer, a slow two-band gated AGC
for gain riding, an equalization section, a gated two-band compressor, and a low-IM
look-ahead limiter. It shares the stereo enhancer, AGC, equalizer, and look-ahead
limiter with the Five-Band structure. The Two-Band and Five-Band compressors are
always active simultaneously. OPTIMOD-PC switches between the structures by send-
ing the output of the desired compressor to the look-ahead limiter's input. Switch-
ing between the compressors occurs via a smooth cross-fade.
setting and occurs gradually. The factory default setting is
control drives the look-ahead limiter harder, reduc-
D
IMIT RIVE
control to prevent the look-ahead limiter from caus-
D
IMIT RIVE
LAT
L D
INAL IMIT RIVE
Table 3-7: Distortion Control Adjustments
L D
INAL IMIT RIVE
INAL
preemphasis. As explained above, you
control when using preemphasis.
Range
–6.0 ... +6.00, Off
–6.0 ... +6.00, Off
0.0 ... 10.0
–10.0 ... +12.0
ORBAN MODEL 1101
control primarily
-
ESS
L drive
IMIT