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Linear Acoustic LA-5180 Metadata Frame Sync/Generator Operation Manual
A Simple Rule:
31 + (dialogue level value) = Shift applied
Example:
31 + (-21) = 10 dB
The most important point to remember is that in setting the dialogue level parameter, you
are providing your listener with an essential service. For your listeners, setting this level
properly means:
•
The volume level is consistent with other programs.
•
The DRC profiles you make available to them work as you intend.
Note that when calibrating a system, if the dialogue level parameter is set to anything other
than -31, the system is not unity gain. For proper alignment, remember to set the dialogue
level parameter to -31 (no attenuation decoder) during calibration. In modern digital sys-
tems where levels are usually unity, this will not be much of an issue but when adjusting
analog to digital converters it could cause quite a bit of confusion.
7.3.2
Dynamic Range Control (DRC)
Different home listening environments present a wide range of requirements regarding dy-
namic range. Rather than simply compressing the audio program to work well in the poor-
est listening environments, Dolby Digital encoders can calculate Dynamic Range Control
(DRC) information and send it via the Line Mode and RF Mode metadata parameters to
the consumer decoder. This metadata can then be applied to the audio signal by the de-
coder to reduce its dynamic range.
Through the proper setting of DRC profiles during content creation, the producer can
provide the best possible presentation of program content in virtually any listening envi-
ronment, regardless of the quality of the equipment, number of channels, or ambient noise
level in the consumer's home.
Many decoders offer the consumer the option of defeating the Dynamic Range Control
metadata, but some do not. Decoders with six discrete channel outputs (full 5.1-channel
capability) typically offer this option. Decoders with stereo, mono, or RF-remodulated
outputs, such as those found on DVD players and set-top boxes, often do not. In these
cases the decoder automatically applies the DRC metadata associated with the decoder's
selected operating mode.
There is separate DRC metadata for the two possible operating modes of the decoder. The
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Metadata
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