TC Electronic LM2 Plug-in - Manual (Page 21)

LM6 - Radar Loudness Meter / 21
EN
Display
LM6/LM2 may use either the measurement unit of LU (Loudness Units) or LUFS
(Loudness Units Full Scale). LU and LUFS are measurements in dB, reflecting the
estimated gain offset to arrive at a certain Reference Loudness (LU) or Maximum
Loudness (LUFS) as defined in BS.1770. Since a common reference point for LU has
not been agreed on at the time of writing, LUFS (or “LKFS”, pointing specifically to
the Leq(R2LB) weighting of BS.1770), might be favored initially to avoid ambiguous
use of the term LU.
The effectiveness of any loudness meter depends on both the graphical appearance
and dynamic behavior of its display, as well as on its underlying measurement
algorithms. A short-term loudness meter also relies on the measurement algorithm’s
ability to output pertinent loudness information using different analysis windows,
for instance, 200-800 ms for running realtime updates. It should be noted how
the optimum size of this window varies from study to study, possibly because the
objective of a running display hasn’t been fully agreed upon.
Formal evaluation of a visualization system is challenging: First of all, one or
more metrics must be defined by which the display should be evaluated. The
correspondence between the sound heard and the picture seen is one aspect to be
evaluated. Another metric could characterize the speed of reading the meter reliably.
In TC Electronic LM2, LM5 and LM6, short-term, mid-term and long-term of loudness
measurements are tied together coherently, and displayed in novel ways (angular
reading and radar) that were preferred in its development and test phases. However,
we remain open to suggestions for further improvement of the visualization of
loudness.