TC Electronic DB6, Manual

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LM6
56 DB6 Single / Multi / AES – Firmware version 1.30
With Dolby AC3 and with low bit rate codecs,
-3 dBFS should be considered the limit, while
legacy platforms requiring emphasis may need
even further restriction. As described in EBU
R128, it is recommended to make full use of the
headroom with true-peaks going to -1 dBFS in
production, and to only restrict peak level further
during distribution/transmission.
LM6 – Main page
LM6 Main page
Descriptors section
Descriptor 1 / Descriptor 2 parameters
Range setting
Loudness Range (standardized in EBU R128 and
abbreviated “LRA”) displays the loudness range
of a program, a film or a music track. The unit is
LU, which can be thought of as “dB on the av-
erage”.
The Loudness Range descriptor quantifies the
variation of the loudness measurement of a pro-
gram. It is based on the statistical distribution
of loudness within a program, thereby excluding
the extremes. Thus, for example, a single gun-
shot is not able to bias the LRA number.
EBU R128 does not specify a maximum permit-
ted LRA. R128 does, however, strongly encour-
age the use of LRA to determine if dynamic treat-
ment of an audio signal is needed and to match
the signal with the requirements of a particular
transmission channel or platform.
Consequently, if a program has LRA measured
at 10 LU, you would need to move the master
fader ±5 dB to make loudness stay generally the
same over the duration of the program (mot that
you would want that).
In production, Loudness Range may serve as
a guide to how well balancing has been per-
formed, and if too much or too little compres-
sion has been applied. If a journalist or video
editor isn’t capable of arriving at a suitable LRA,
he could be instructed to call an audio expert
for help.
The following may be regarded as initial produc-
tion guidelines:
– HDTV and digital radio:
Stay below LRA of 20 LU.
– SDTV:
Stay below LRA of 12 LU.
– Mobile TV and car radio:
Stay below LRA of 8 LU.
Remember to use LRA the other way around,
too: If there is an ideal for a certain genre, check
its LRA measure, and don’t try go below it. LRA
should not be used for Limbo.
Allow programs or music tracks the loudness
range they need, but not more than they need.
Loudness Range may also be measured on a
broadcast server to predict if a program is suit-
able for broadcast without further processing.
LRA is even a fingerprint of a program and stays
the same downstream of production if no dy-
namics processing has been applied. You may
even check the number out of a consumer’s set-
top box to verify that distribution processing and
Dolby DRC has been disabled.
As with Program Loudness and Loudness Max,
the meter should be reset before measuring
LRA.
Prog. Loudn. setting
Program Loudness returns one loudness num-
ber for an entire program, film or music track. Its
unit is LUFS. Some vendors and countries use
the unit “LKFS” or “LUFS”, but all three desig-
nate the same: An absolute measure of loudness
in the digital domain, where the region around
“0” is overly loud and not relevant for measur-
ing anything but test signals. Expect readings of
broadcast programs in the range between -28
and -20 LUFS.
Program Loudness is used as a production
guideline, for transparent normalizing of pro-