Loudness Meters: Absolute/Relative Scales …

Professional audio Loudness Meters display Program (Integrated) Loudness using an Absolute scale measured in LUFS. For example the EBU R128 Program Loudness target is -23.0 LUFS (Loudness Units Relative to Full Scale).

In 2006 when the ITU defined new audio loudness measurement guidelines, the general consensus was that many audio engineers would prefer to mix/normalize to the familiar “0” level as the compliance target on a loudness meter. A Relative scale option was implemented that displays Loudness Units(LU), where 0 LU equals the corresponding LUFS compliance target.

So for EBU R128 … 0 LU = -23.0 LUFS. (By the way 1 LU = 1 dB).

In the snapshot below you can see my Nugen VisLM Loudness Meter set to display Absolute scale (left) and Relative scale (right).


Of course in most cases this scale and corresponding target is customizable. For example I advocate -16.0 LUFS as the loudness target for audio distributed on the internet. By defining -16.0 LUFS as my compliance target in a meter’s setup options, 0 LU on the Relative scale would then equal -16.0 LUFS on the Absolute scale.

Below is a basic side by side comparison of EBU R128 Absolute and Relative scales:



Loudness Meters: Absolute/Relative Scales …