Orban OPTIMOD-FM 8600Si, Operating Manual

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OPERATION ORBAN MODEL 8600Si
period of quiet music to allow a crescendo to get louder than it would using the
8600Si's relatively fast integration time. However, what happens if someone starts
an arbitrary 60-second measurement period not at the beginning of the quiet pas-
sage but at the beginning of the crescendo?
Because an automatic MPX power controller does not know what is coming after
the crescendo, it must reduce the level of the crescendo so that it complies with the
MPX requirement over with an integration time that is shorter than 60 seconds.
Otherwise, it might have to dramatically reduce the level of following (as yet un-
known) program material in order to ensure that the MPX power limit is not ex-
ceeded over the 60-second measurement period in question. This kind of gain
pumping would be far worse than the pumping produced by using a relatively short
integration time.
MPX Pwr Ctrlr Gate : To minimize audible side effects of the MPX power control-
ler’s gain reduction, its release time is dual-speed and changes as a function of the
audio level: if the audio level is below a preset threshold, the slower time constant
activates. There are five preset values for the gating, which set the level below
which gating occurs, as well as the release times above and below the threshold.
Higher-numbered presets provide slower release times both above and below the
gating threshold.
Unlike the
MPX P
OWER
T
HRESHOLD
control (a System control), the
MPX P
WR
C
TRLR
G
ATE
control is part of the active processing preset.
•
Preset 0 : No gating: Works like Orban’s older, non-gated MPX power controller.
•
Preset 1 : Only the quieter passages are gated and the gated release is faster
than it is in the other presets. Created to maximize loudness within the BS.412
limit while providing more on-air dynamics and preventing unnecessary gain
pump-ups.
•
Preset 2 : A compromise between Preset 2 and 3. Works well with more dy-
namic, more open-sounding presets.
•
Preset 3 : Recommended for most CHR-style presets. Quieter parts of the music
are effectively frozen to achieve less audible BS412 control. It is still possible to
stay at the BS.412 limit most of the time.
•
Preset 4 : A general-purpose preset that works well with most processing pre-
sets. When on-air processing preset is designed well, it is still possible to stay at
the limit with nearly inaudible BS412 control up to 2dB gain reduction.
•
Preset 5 : The controller gates on nearly every power-drop so that the release
rate is almost always very slow. Designed to act only as a protection limiter to
sound nearly like no BS412 controller is working at all while still getting loud-
ness benefits from it. BS.412 gain reduction of up to 3dB is possible without ob-
jectionable side effects.