Omnia Audio Omnia 8x - Manual (Page 27)

Interpreting the Gain Reduction Meter Displays
Through careful observation of the processing bargraphs, significant information can be acquired and analyzed
about the audio signal on a moment-by-moment basis. The yellow bar shows the average value of the gain
reduction, while the floating ball indicates the peak value of gain reduction.
Average value of gain reduction
Gain Reduction scale Peak value of gain reduction
Gain reduction meter (typical)
Since the processing algorithms in Omnia 8x 'adapt' to the audio, it is capable of performing many different
processing functions at different times. The processing display bargraphs may appear to indicate different kinds of
operation with different program material. This behavior is primarily based on dynamic range differences in the
program material. For program material that is already processed (like most modern popular music CD’s) and
lacking dynamic range, the bargraphs will indicate differently than they will with material that has a high degree of
dynamic range. This is because audio signals that lack dynamic range will possess a lower peak to average ratio.
Conversely, audio signals with a wide dynamic range possess a higher peak to average ratio. The Omnia 8x adapts
differently to each case.
For program material that has low dynamic range (high RMS and low peak levels), there will be more activity in the
WB-AGC section and less activity in the Multiband Processors. The WB-AGC will respond to high RMS energy,
while the Multiband section receives lower peak energy so will not show as much activity. Sometimes the
Multiband section may not indicate any action at all. For Omnia 8x, this is completely normal! Examples of this
behavior might be seen with heavily processed commercials or music, or with music passages of sustained level. A
good example is the Aerosmith CD “Pump.” This recording has very little dynamic range. Try any up-tempo
selection from this disk and you will see the Wideband-AGC section make initial adjustments along with small
amounts of multiband limiting. Once adjusted, the Wideband-AGC section will stay deep in gain reduction,
although with little movement, and action within the multiband limiters will be minimal.
When the programming has wide dynamic range (low RMS and high peak levels), the opposite will occur. The
Multiband section becomes more active, while the WB-AGC section will appear to have less activity. During these
events, the Multiband sections may be working aggressively, while the WB-AGC section indicates little activity.
Good examples of programming able to cause this behavior: vocal passages, live voice, classical music, and
passages with high transient levels. Good test examples: almost anything classical, as well as almost anything by
Steely Dan!
Also keep in mind that the WB-AGC section is designed to operate much more slowly than the Multiband sections,
primarily because of the nature of each function. Remember that the WB-AGC section operates on the program's
RMS (average) energy. During gain calculations, the incoming program's “average” level is established, and gain
adjustments, if needed, are made based on those calculations. This is why the WB-AGC section will appear to move
slower as it makes changes over relatively long time periods.
The intent of the Multiband section is to normalize the spectral balance and provide control of the peak levels. Peak
energy must be detected and adjusted in a quick and accurate manner while, at the same time, not interfering with
the sonic integrity of the audio signal. For this reason, the Multiband sections operate faster, with special
background instructions to govern their behavior, and strictly on an as-needed basis.
Since the processing displays are capable of providing a wide range of information, we do not recommend setting
up the system based on any specified meter indications. Instead, we recommend setting up the processing by using
your ears to judge the sound. We've provided the meters only to analyze the signals and aid you in adjusting the
specific parameters needed to achieve your desired sonic results. Like a speedometer, the meters are a guide, not the
road!
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