Omnia 6 Use and Installation Guide – Version 1.00a
52
52
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-6fm '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 applied program material. For program material that is already processed or lacking
dynamic range, the bargraphs will indicate differently than with material that possesses a high degree of
dynamic range. This is because audio signals that lack dynamic range, naturally or by previous processing,
will possess a lower peak to average ratio. Conversely, audio signals with a wide dynamic range possess a
higher peak to average ratio. The Omnia6-fm adapts differently to each case.
For program material that has low dynamic range (or high RMS and low peak levels), there will be more
activity in the AGC sections and less activity in the Limiters. This behavior is due to the AGC sections
response to high RMS energy, while the Limiters are reacting to lower peak energy. Sometimes the Limiter
section may not indicate any action at all, especially on the top three bands. For Omnia6-fm, 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 limiting. Once adjusted, the Wideband-
AGC section will stay deep in gain reduction, although with little movement, and action within the limiters
will be minimal.
When the programming has wide dynamic range (low RMS and high peak levels), the opposite will occur.
The Limiter section becomes active, while the AGC section will appear not to respond as much. During
these events, the Limiter sections could be working aggressively, while the AGC sections indicate 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 AGC sections are designed to operate much more slowly than the Limiter
sections, primarily because of the nature of each function. Remember that the AGC sections operate on the
