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).

scale-blog

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:

figg-scale

-paul.

Loudness Meters: Absolute/Relative Scales …