Orban OPTIMOD-FM 8600Si, Руководство по эксплуатации

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OPTIMOD-FM DIGITAL OPERATION
3-47
Bass Clip Thresh sets the clipping threshold of Orban’s patented embedded bass
clipper, which is used only in the FM processing chain and not in the HD chain. The
clipper is embedded in the multiband crossover 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
L
ESS
-M
ORE 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 do not smash
against the back-end clipping system, causing overt intermodulation distortion be-
tween the bass and higher frequency program material.
Some 8600Si users feel that the bass clipper unnecessarily reduces bass punch at its
factory settings. To accommodate these users, the threshold of the bass clipper is us-
er-adjustable. The range (with reference to the final clipper threshold) is 0 to –6 dB.
As you raise the threshold of the clipper, you will get more bass but also more dis-
tortion and pumping. Be careful when setting this control; do not adjust it casually.
Listen to program material with heavy bass combined with spectrally sparse mid-
range material (like a singer accompanied by a bass guitar) and listen for IM distor-
tion induced by the bass’ pushing the midrange into the clipping system. In general,
unless you have a very good reason to set the control elsewhere, we recommend
leaving it at the factory settings, which were determined following extensive listen-
ing tests with many types of critical program material.
HF Clipping determines the amount of protection provided by the 8600Si’s high
frequency multiband clipper. This control was first introduced in the 8200 and al-
lowed users to trade off distortion against brightness. Because of subsequent im-
provements in the clipping system, this control is much less useful than it was in the
8200 and we recommend always setting it to “0.”
Final Clip Drive control adjusts the level of the audio driving the back end clipping
system that OPTIMOD-FM uses to control fast peaks. The
F
INAL
C
LIP
D
RIVE control
primarily determines the loudness/distortion trade-off.
Turning up the
F
INAL
C
LIP
D
RIVE control drives the final clipper and overshoot com-
pensator harder, reducing the peak-to-average ratio, and increasing the loudness on
the air. When the amount of clipping is increased, the audible distortion caused by
clipping is increased as well. Lower settings of the
F
INAL
C
LIP
D
RIVE control reduce
loudness, of course, but result in a cleaner sound.
8500-Style Peak limiter Controls
PC Remote Name Range
OSComp Dr –2.0 … +2.0
BassClpThre –6.0 … 0.00
SpeechBCTh –6.0 … 0.00
BassClpMode Soft, Medium, Hard, LLHard
Hard Clip Shap 0 … 10
HF Clipping 0 ... 6.0 dB
Table 3-6: 8500-Style Peak Limiter Controls