Orban Optimod-TV 8382 Operating Manual Download

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OPTIMOD-TV DIGITAL

OPERATION

3-41

clipper.

Like any other dynamics processing, the distortion-controlling section can produce
artifacts of its own when overdriven. These artifacts can include loss of definition,
smeared high frequencies, a sound similar to excessive compression, and, when op-
erated at extreme settings, audible intermodulation distortion. In television process-
ing, it is wise to back off the

LIM

control to prevent such artifacts.

MB LIM THR

(“Multiband Limit Threshold”) sets the threshold of the clipping dis-

tortion controller with reference to the threshold of the final clipper, in dB.

The most effective setting for this control is “0dB” for almost all program material.
For the

NEWS-TALK

and

SPORTS

presets, we set the

control slightly be-

low “0.” This ensures the cleanest possible speech quality at the cost of highest
loudness. If you want higher loudness in these presets, you can edit them to increase
the setting of the

LIM

THR

control.

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 downward ex-
pander with a program-dependent low-pass filter. These functions are achieved by
introducing extra gain reduction in the multiband compressor. You can see the ef-
fect of this extra gain reduction on the gain reduction meters.

Ordinarily, the gating on the AGC and multiband limiter will prevent objectionable
build-up of noise, and you will want to use the single-ended noise reduction only on
unusually noisy program material. In television audio, it is particularly useful in live
news and sports.

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

control of the noise reduction system to complement 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 modulation—a puffing or breath-
ing 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 complements the program material of the

moment.