Cobalt Digital COMPASS 9086 Embedded Audio Loudness Processor - Manual (Page 57)

9086-OM (V4.3) 9086-SD PRODUCT MANUAL 3-29
Operating Instructions
9086 Function Submenu List and Descriptions
Audio Loudness Processing
Provides active loudness processing of selected stereo
channels sent by the card.
• Channel Selection Separate drop-down lists for applying any combination of card audio
outputs (Embed Out Ch1 thru Embed Out Ch 16 to each of the loudness
processor inputs.
Note: Set any unused channel inputs to Silence.
• Processing Profile Preset Selection
Turns loudness processing on and off, and allows selection of preset
loudness profile best suited for the program material and/or model of
processing desired as follows:
• TV 5B General – This is the general, recommended preset for all types
of content. It provides moderate dynamic range compression and is
calibrated to produce audio having an average dialog loudness of
-27 LKFS with no additional output level trim. Use of this preset as an
initial setting is recommended.
• TV 5B Light – Similar to TV 5B General, this preset varies in that
multi-band compression is reduced closer to 2:1, thereby providing a
more gentle action.
Note: This preset sacrifices agility in loudness control in favor of a more
gentle compression profile; this preset may not be suitable for
some material.
• TV 5B Heavy – Similar to TV 5B General, this preset varies in that
multi-band compression is increased for greater level density/adherence
to target at the expense of dynamic range.
• TV 5B Loud – Similar to TV 5B Heavy, but with a louder, more punchy
perception.
• ITU Loud Limit – Utilizes a specially tuned input AGC plus multi-band
and a final limiter to gradually adjust the average program loudness to
an internally set AGC value, with the multi-band and final limiters acting
until the AGC gains control of the level. This preset is most appropriate
for ingest or live program material.
Note: This preset bypasses the multi-band AGC. As such, it has less
ability to manage spectral balance.
• Protection Limit – Bypasses all processing except for final output
limiter, which is set only to prevent overload.
Note: Unless the audio received has already been loudness processed,
this setting is typically not recommended.
• Master Output Gain Control Allows fine adjustment of the overall output gain.
(-20.0 dB to 11 dB range in 0.1 dB steps; default = 0.0 dB)
Note: This control is primarily useful in matching the output level to an
alternate LKFS target level if required. Also, it is useful (where
desired) in matching various Processing Profile presets to have
similar output levels. The loudness processor has a default target
loudness of -24 LKFS.
Note: (USA) ATSC A/85 and the CALM Act (H.R. 1084/S. 2847) requires that when real-time loudness processing is
applied using a fixed target loudness of -24 LKFS, downstream AC-3 encoding must correspondingly use a
fixed dialnorm value of -24. The default target loudness (as set by the loudness processor Master Output Gain
Control) is -24 LKFS. When loudness processing is engaged, make certain AC-3 dialnorm is set as
described here.
Table 3-2 9086 Function Submenu List — continued