Level-gated loudness measurement ignores quiet passages so it tracks foreground loudness

Programme Loudness in EBU R 128 is not a simple average of the whole signal: it uses the level-gating method of ITU-R BS.1770 Eq.(7), which excludes passages below a relative threshold before averaging. Because near-silent and very quiet sections are gated out, the resulting integrated value reflects the loudness of the foreground content (speech, dominant music) rather than being dragged down by pauses. This gating is what lets programmes with a wide loudness range be matched consistently: two items with very different amounts of silence still integrate to comparable loudness values. The measurement is otherwise made on the signal in its entirety, without emphasising any specific foreground element.

Examples

A drama with long silent pauses and a wall-to-wall pop track can both read -23 LUFS integrated because gating removes the drama’s silences before averaging. Without gating, the drama would measure much quieter and be turned up too far.

Assessment

Why does EBU R 128 gate out low-level passages before computing integrated loudness? What problem would an ungated long-term average cause for a programme with a wide loudness range?