TC Electronic LM2 Plug-in - Manual (Page 15)

LM6 - Radar Loudness Meter / 15
EN
Loudness Unit
LUFS/LKFS
All measurements of program loudness and sliding loudness are shown in units of
LUFS/LKFS, that is, in Loudness Units on the absolute scale. This is the normal
setting for the Loudness Unit parameter, that we recommend for most applications.
Loudness Range is always shown in units of LU, because it is basically a
measurement of ‘range’ or of the distance between a high and a low loudness level.
LU
In this setting, measurements of program loudness and sliding loudness are shown
in units of LU, that is, in Loudness Units on a relative scale. The 0 LU is by definition
the target loudness level, such as -23.0 LUFS. So by selecting ‘LU’, one can
immediately see if a loudness level is above the target level (e.g. +1.2 LU) or below
(e.g. -3.4 LU).