Cobalt Digital FUSION 3G 9985 3G_HD_SD Loudness Processor - Manual (Page 131)

9985-OM (V1.18) 9985 PRODUCT MANUAL A-3
Appendix A
User-Adjustable Parameters
Parametric Eq(ualization)
Three bands of parametric equalization are provided for fine tuning if
necessary. None of the factory-supplied presets use the parametric equalizers,
but they are provided to create notch filters or other effects if necessary. Each
filter has a gain control with a ±12dB range, a center frequency control that
varies from 20 Hz to 22.050 kHz, and a bandwidth or “Q” control that varies
between 0 and 10. Normal default settings for all bands are Gain = 0dB (i.e.,
bypassed).
Input AGC
The input AGC is a very slow acting front-end gain control with a 36dB gain
range whose only purpose is to make sure that the following processing stages
are fed with the correct average audio levels. It is basically the automatic
equivalent of an operator slowly riding a gain control on a console to keep the
audio close to reference level. Wideband in nature, the AGC is not meant to
perform rapid gain reduction or expansion as its actions will be more audible,
as with all wideband gain processors. As a slow gain rider, its actions are
nearly inaudible thanks to the multiband processing that follows it. The AGC
has two stages of gating where the gain expansion is slowed or stopped to
prevent background noise increasing.
Adjustable parameters are:
• Gating Thresh(old): 0 dBFS to -90 dBFS (default: -21 dBFS)
Gating sets the point at which the AGC release time is made extremely slow
to prevent increasing background noise and allow the AGC to return to
unity gain.
• Freeze Thresh(old): 0 dBFS to -90 dBFS (default: -31 dBFS)
Freeze stops all gain change (i.e. when the audio drops to silence), and
remains frozen at its current gain value until the threshold is exceeded.
Note: Very quiet audio (such as a golf match) benefits from having processing
frozen when input audio drops below a given level to prevent “boosting the
cricket” sounds.
• Ratio: 1:1 to Inf:1 (default: 12.0:1)
• Range: 0 dB to 36 dB (default: 24dB)
Range sets how much gain expansion above unity is performed, and this
amount is subtracted from the total AGC gain range of 36dB, so the default
value allows for 24dB of expansion and 12dB of compression. This
adjustment
is reflected in real time by changing the AGC meter scale.
• Threshold: -18 dBFS to 0 dBFS (default: -16dBFS)
• Attack: 0 - 150, slowest - fastest (default: 21)
• Release: 0 - 150, slowest - fastest (default: 47)