Steinberg WAVELAB 8.5 RETAIL SOFTWARE 45370 数据表

This measures the dynamics of the audio signal. It reports the ratio between the 
loudest and the quietest (but non-silent) sections. The audio is divided into small 
blocks. There is one audio block every second and each block lasts 3 seconds 
(analyzed blocks overlap).

The top 10 % of the quiet blocks and the top 5 % of the loud blocks are excluded 
from the final analysis. The calculated loudness range is the ratio between the 
loudest and quietest remaining audio blocks. This measurement helps to decide if 
and how much compression or expansion can or should be applied to the audio.

When a digital signal is converted to an analog signal, the EBU R-128 recommends 
measuring an estimation of the real peaks, rather than relying on digital peaks, to 
avoid clipping and distortion. This is accomplished by over-sampling the signal 4 
times and retaining the peak values.

The EBU R-128 proposes naming and units conventions:

•

A relative measurement, such as a value relative to a reference level: “LU” as 
“Loudness Unit” (1 LU is 1 dB).

•

An absolute measurement, LUFS as “Loudness Unit Full Scale”. 1 LUFS can 
be understood as 1 dB in the AES-17 scaling.

When WaveLab relates to the EBU R-128 loudness, these units are used rather 
than dB.