Orban Optimod-AM 9400 Operating Manual Download Page 184

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OPERATION ORBAN

MODEL

9400

smeared high frequencies, a sound similar to excessive compression, and, when op-
erated at extreme settings, audible intermodulation distortion. You can adjust the

LIM

control to prevent such artifacts or to use them for coloration in “highly

processed” formats.

MB LIM THR

(“Multiband Limit Threshold”; analog AM chain only) sets the thresh-

old of the clipping distortion controller (in dB) with reference to the threshold of
the final clipper.

A good compromise setting for this control is “0dB.” However, the loud-
est and most intense-sounding presets rely on considerable clipping to
achieve their loudness. For these presets, we found it necessary to set the

control higher than “0” to permit more clipping depth. In

some cases, this results in substantially objectionable distortion artifacts
with isolated program material. However, this is the price to be paid for
this extreme level of on-air loudness.

Settings below “0 dB” will decrease audible clipping distortion. Such set-
tings may be appropriate when the multiband compressor is producing
high density via a fast release time and considerable gain reduction.

DwnExp Thr

(“Downward Expander Threshold”) determines the level below which

the single-ended noise reduction system’s downward expander begins to decrease
system gain, and below which the high frequencies begin to become low-pass fil-
tered to reduce perceived noise. Activate the single-ended dynamic noise reduction
by setting the

WNEXP

control to a setting other than

OFF

The single-ended noise reduction system combines a broadband down-
ward expander with a program-dependent low-pass filter. These func-
tions are achieved by introducing extra gain reduction in the multiband
compressor. You can see the effect of this extra gain reduction on the
gain reduction meters.

Ordinarily, the gating on the AGC and multiband limiter will prevent ob-
jectionable build-up of noise and you will want to use the single-ended
noise reduction only on unusually noisy program material. Modern com-
mercial recordings will almost never need it. Its main use is in talk-
oriented programming, including sports.

Please note that it is impossible to design such a system to handle all
program material without audible side effects. You will get best results if
you set the

control of the noise reduction system to com-

plement the program material you are processing. The

should be set higher when the input is noisy and lower when the input is
relatively quiet. The best way to adjust the

control is to start

with the control set very high. Reduce the control setting while watching
the gain reduction meters. Eventually, you will see the gain increase in
sync with the program. Go further until you begin to hear noise modula-
tion — a puffing or breathing sound (the input noise) in sync with the
input program material. Set the

control higher until you can

no longer hear the noise modulation. This is the best setting.

Obviously, the correct setting will be different for a sporting event than
for classical music. It may be wise to define several presets with different
settings of the

control, and to recall the preset that com-

plements the program material of the moment.