Omnia 6 Use and Installation Guide – Version 1.00a
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Multiband AGC Windows
Each of the multiband AGC's has its own set of controls similar to those in the Wideband AGC section.
The four controls in these windows, Attack, Release, Make-Up Gain and Gate Threshold, and the two
parameter selections, RTP Speed and RTP Level, function like those in the Wideband AGC window.
Adjustment strategies are similar, however in the mutiband AGC sections adjustments are on a "per-
frequency band" basis.
Low Band AGC shown as example – other bands are identical
As with any multiband processor, improper adjustment can exaggerate noise at high frequencies,
particularly with older recordings that possess a good deal of tape hiss. This can especially occur if the
higher AGC bands are driven so that significant gain reduction occurs, and the band's gating control is set
to the lower end of the scale. During audio segments that have little or no HF content, the AGC will try to
increase its gain in an effort to restore treble balance. Even during periods when the gate function is in the
default Freeze mode, the problem might still exist with some programming. In those situations, even an
increase of the gate threshold control to higher numbers may not help the situation.
Therefore, each band of the multiband AGC incorporates a Return To Platform (RTP) feature similar to
that available within the Wideband AGC process block. When the RTP function is set to a value other than
Freeze, the band gain will be forced to recover its gain to a static value higher than might be achieved if the
control was set to Freeze. This will reduce hiss and other high frequency noise. The RTP levels can be
tailored for each individual AGC band as desired.
Use the RTP Speed to set the amount of time it will take the AGC to return to the set platform level. There
are four choices: Freeze, Slow, Med, and Fast. The default setting is Freeze, which freezes the gain
whenever gating occurs. Therefore, to activate the RTP for that band, just select a speed. As mentioned
previously, the RTP speed is slightly affected by the value of the attack time that is set for that band. The
opposite is not true: RTP Speed does not affect the operation of the attack/release functions. Freeze can be
considered the “off “ mode for the RTP function.
Use RTP Level to set the platform level. There are three choices: -5dB, -10dB and –15dB. The default
