Omnia Audio Omnia F/XE - Manual (Page 44)

42 | Section 5
In Omnia F/XE’s implementation, the crossover network is carefully time-aligned so that the recombined
spectrum remains flat, regardless of the amount of gain control being applied within any band. This true
phase linear response assures that harmonic overtones are not displaced in time. The result is a truer, more
natural, and more musical Omnia sound. The crossover frequencies are not adjustable.
Multiband AGC Sections
The Multiband AGC sections are similar in character to the wideband AGC described above, but they are
expanded to three bands. This section has the ability to significantly add power and loudness to the audio
while tailoring and pre-processing it for delivery to the final limiter section. The system uses different
algorithms for each of the bands;
♦ The low and mid bands use a feedback configuration, which produces a larger, warmer sound on
lower frequencies.
♦ The high band utilizes a feed forward design that maintains a more open, natural and musical texture
on higher frequencies.
As with any multiband processor, improper adjustment can exaggerate noise at high frequencies, particu-
larly with older recordings that possess a good deal of tape hiss. This can especially occur if the highest AGC
band is 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.
Since the user parameters are the same for all three bands, only the LF Band will be detailed here.
Drive
Drive sets the audio level that enters the WB-AGC. Increasing the Drive will produce more compression.
This control is calibrated between –6dB and +6dB, and adjusts the signal level into the Wideband AGC.
Drive should be adjusted to net approximately 12dB of gain reduction with typical programming. Too little
gain reduction can defeat the “leveling” function of the Wideband AGC. Too much gain reduction has little
additional benefit. Nominal gain reduction values for the Wideband AGC are between 10 and 15dB.
Release
Release controls the speed of recovery for any given amount of gain reduction. Faster action yields less
dynamic range and the presence of more density to the audio. The Release control sets the time constants in
relative terms using Slow, Medium, and Fast. Because the time constants are program-dependent, calibrat-
ing these controls in absolute time values (ms/dB) would be useless—therefore simple terminology is used.