Wideband Agc; Phase Linear Crossovers; Five Band Agc; Enhancer Section - Omnia -6EX / EXi Installation And Operation Manual

Wideband AGC: A very flexible wideband leveler section provides smooth, transparent control of the input
program. This is achieved through two significant Omnia innovations, a dual referenced release gate and a hidden,
intelligent "makeup" gain algorithm. The dual gate reference is a unique process that correlates the dynamics of the
audio input signal to a "rolling" reference level, and from that information makes conditional decisions affecting the
character of the release function.
A user-adjustable Make-Up Gain feature incorporates a hidden control signal that determines when the amplitude of
the input program suddenly falls to a reduced level. It then adjusts the side chain gain in order to quickly "fill in"
the softer program passages so that the average level is increased. This allows the AGC function to operate with
slower overall time constants, while significantly increasing the average audio level. Slower "average" time
constants yield lower intermodulation distortion, contributing to Omnia's trademark sound.
Using Classical music for an example, the orchestra often plays forte, and then enters abruptly into a quiet passage.
Conventional AGC algorithms would hold the softer passage down until it was able to slowly recover at the static
release time setting, making such passages nearly inaudible at normal listening levels. Omnia-6's makeup gain
function allows a hidden, faster time constant to provide quick recovery, but only during the softer passage. As soon
as the orchestra starts to play louder, the "makeup" time constant yields control back to the primary AGC circuit,
returning gain to the previous platform level. This sophistication preserves the dynamic integrity of the signal while
greatly enhancing the listenability of the program.
A built-in, multi-stage phase rotator ensures symmetrical clipping of positive and negative peaks, making better use
of the symmetrical limitations of the FM medium. (This feature may be defeated for a more musically transparent
sound at the expense of possibly increased distortion on certain voice material.)
Phase Linear, Time Aligned Crossovers: Most multiband audio processors make a compromise in the crossover
area in order to provide a flat dynamic frequency response. This is done to avoid audible peaks or dips in the
recombined frequency response as the individual band gains change during processing. In an effort to minimize this
problem, most processors use a fixed phase-offset in the crossovers. While such treatment helps to minimize
frequency response peaks and dips, it also results in a loss of phase linearity, increasing "smearing', and reducing
musical clarity.
In Omnia-6's DSP implementation, the crossover networks are 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: that truer, more natural, and more
musical "Omnia sound".
Additionally, Omnia-6EX features separate crossovers for the multiband AGC sections. The AGC crossover section
features user adjustable crossover frequencies (exclusive to Omnia), while the limiter section contains its own six-
way crossover with factory optimized non-adjustable crossover frequencies and slopes.
Five-Band AGC: Similar in character to the wideband AGC described above, but expanded to five bands, this
section has the ability to add significant power and loudness to the audio while tailoring and pre-processing it for
delivery to the enhancement and multiband limiter sections. Each of the four crossover frequencies has five user-
adjustable settings.
Enhance: This section contains the Bass EQ and Stereo Enhancement controls. In the Omnia-6EX's unique signal
processing architecture, these controls are placed in their optimal position — between the multi-band AGC and
Limiter sections.
Omnia-6ex Use and Operation Manual – V: 1.20
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