Manual

LM2 (optional)
Loudness Pilot English Manual (2014-10-07) 102
Long-term measurements
Universal descriptors may be used to make pro-
gram-duration measurements, or you may “spot-
check” regular dialog or individual scenes as re-
quired. It is recommended not to measure pro-
grams of a shorter duration than approximately
10 seconds, while the maximum duration may be
24 hours or longer.
Reset button
Before a new measurement, click the Reset but-
ton. This will reset the descriptors, the radar and
the true-peak meters.
Run the audio, and watch the Radar and the de-
scriptor fields update accordingly.
While the Radar will update instantly, the de-
scriptors will wait five seconds into the program
before showing the first readings. This is normal.
Even though the first five seconds of a program
are not shown instantly, they are included in the
descriptor calculations.
LM2 incorporates an intelligent gate which dis-
criminates between foreground and background
material of a program. Consequently, measuring
won’t start before audio has been identified. The
intelligent gate also pauses measurements dur-
ing periods that only contain background noise,
and during fade-outs of music tracks.
Universal Descriptors
and Dolby LM100
Unlike methods that measure dialog only, LM2
may be used with any type of audio, including
dialog.
If you wish to measure dialog, it is recommended
to do a manual spot check of a program or a film.
Find 10-30 seconds of regular dialog and mea-
sure it with LM2. Where dialog may be soft, regu-
lar or loud, and shift by more than 15dB inside
a film, regular dialog tends to be less ambiguous
and more consistent across a program.
For compatibility with a proprietary measure
such as Dolby LM100, only some of these meters
are updated to use ITU-R BS.1770 and Leq(K)
while others are locked at Leq(A). The software
version of LM100 should be 1.3.1.5 or higher in
order for it to comply with BS.1770, and to have
its average loudness reading be compatible with
Program Loudness in LM2.
Even used just on speech, Leq(A) is not a precise
approximation to perceived loudness, so please
update the unit to BS.1770 to obtain similar read-
ings and predictable results.