Orban Optimod-PC 1101, Operating Manual

Page: 168 / 258

3-48
OPERATION ORBAN MODEL 1101
In the Five-Band structure, the sum of band 1 and 2 drives the clipper. In the Two-
Band structure, the Bass band drives the clipper.
Bass Clip Shape allows you to change the knee of the input/output gain curve of
the bass clipper. It allows you to control the shape of the “knee”—the transition be-
tween no clipping and flat topping. “0” provides the hardest knee, where the tran-
sition between linear operation and flat topping occurs abruptly as the clipper’s in-
put level is changed. “10” is the softest knee, where the transition starts 6 dB below
B
ASS
C
LIP
T
HRESH
setting and occurs gradually. The factory default setting is “7.6.”
See Figure 3-4 on page 3-47.
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
INAL
L
IMIT
D
RIVE
control primarily
determines the loudness/distortion trade-off.
Turning up the F
INAL
L
IMIT
D
RIVE
control drives the look-ahead limiter harder, reduc-
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 2-25), 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
INAL
L
IMIT
D
RIVE
control to prevent the look-ahead limiter from caus-
ing audible gain pumping.
You may find it illuminating to recall several Factory Presets, adjust L
ESS
-
M
ORE
to several points in its range, and then open the Full Control screen
to examine the trade-offs between the release time and F
INAL
L
IMIT
drive
made by the factory programmers. However, note that all Factory Presets
were created to complement F
LAT
preemphasis. As explained above, you
must turn down the F
INAL
L
IMIT
D
RIVE
control when using preemphasis.
Transient Enhance is mainly useful in mastering. This control allows you to insert
an audio delay in the sidechain of the five-band compressor. By delaying the gain
control signal, this allows attack transients to pass through the multiband compres-
sor uncompressed, which can increase punch. There is a tradeoff between this con-
trol and the activity of the look-ahead limiter, which will have to eliminate attack
Distortion Control Adjustments
Name Range
Bass Clip Threshold –6.0 … +6.00, Off
Speech Bass Clip Threshold –6.0 … +6.00, Off
Bass Clip Shape 0.0 … 10.0
Final Limit Drive –10.0 … +12.0
Transient Enhance 0…10 ms
Dialnorm –31…–11 dB, Global
Table 3-7: Distortion Control Adjustments