Optimod-AM 9400 V1.2 Operating Manual - Orban

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OPERATION ORBAN MODEL 9400
zero. For example, to limit an excessively wide image while preventing more than 3
dB difference in gain between the sum and difference channels, set the AGC
MAXIMUM DELTA GAIN REDUCTION control to 3.0 and the AGC MASTER DELTA THRESHOLD
control to some positive number, depending on how much automatic width control
you want the 9400 to perform.
AGC Bass Delta Threshold works the same as AGC MASTER DELTA THRESHOLD, but
applies to the bass band. You will usually set it the same as AGC MASTER DELTA
THRESHOLD.
Clipper Controls
The clipper controls apply only to the analog AM processing chain.
The HD AM chain uses a look-ahead limiter employing a different technology
than the distortion-cancelled clipper used in the AM analog
chain.
Bass Clip (“Bass Clip Threshold”) sets the threshold of Orban’s patented embedded
bass clipper with reference to the final clipper. The bass clipper is embedded in the
multiband crossover (after bands 1 and 2 are summed) so that any distortion created
by clipping is rolled off by part of the crossover filters. The threshold of this clipper is
usually set between 2 dB and 5 dB below the threshold of the final limiter in the
processing chain, depending on the setting of the LESS-MORE control in the parent
preset on which you are basing your Modify adjustments. This provides headroom
for contributions from the other three bands so that bass transients don’t smash
against the back-end clipping system, causing overt intermodulation distortion between
the bass and higher frequency program material.
Some 9400 users feel that the bass clipper unnecessarily reduces bass punch at its
factory settings. Therefore, we made the threshold of the bass clipper useradjustable.
The range (with reference to the final clipper threshold) is 0 to –6dB. As
you raise the threshold of the clipper, you will get more bass but also more distortion
and pumping. Be careful when setting this control; do not adjust it casually. Listen
to program material with heavy bass combined with spectrally sparse midrange
material (like a singer accompanied by a bass guitar) and listen for IM distortion induced
by the bass’ pushing the midrange into the clipping system. In general, unless
Clipper Controls
Full Modify Name Advanced Name Range
--- Overshoot Compensator Drive –2.0 … +2.0
BASS CLI Bass Clip Threshold –6.0 … 0.00 dB
B-CL SHAP Bass Clip Shape 0 … 10
BASS MODE Bass Clip Mode Soft, Med, Hard, LLHard
--- Speech Bass Clip –6.0 … 0.00 dB
FINAL CLIP Final Clip Drive –3.0 … +5.0 dB
HF-CL HF Clip Threshold –16…0.00, Off
--- Speech Bass Clip Threshold
--- Overshoot Comp Drive –2.0 … +2.0
Table 3-6: Clipper Controls