Loudness

In August 2010, the EBU published the first version of its Loudness Recommendation EBU R128 (now in version 3.0). It tells how broadcasters can measure and normalise audio using Loudness meters instead of Peak Meters (PPMs) only, as has been common practice.

Set of Loudness specs

EBU R 128 is the result of several years of intense work by the audio experts in the EBU PLOUD Group, led by Florian Camerer (ORF). The Recommendation is accompanied by specific guidance for short-form content (EBU R 128s1), a Loudness Metering specification (EBU Tech 3341), a Loudness Range descriptor (EBU Tech 3342), Production Guidelines (EBU Tech 3343) and Distribution & Reproduction Guidelines (EBU Tech 3344). An EBU Technical Review Article describing the fundamental change in audio in broadcasting is available: On the way to Loudness Nirvana, as is an article on distribution aspects: Loudness in Distribution.

Test signals

The EBU Loudness test set v5.0 offers various sequences to test loudness meters for (minimal) compliance. It also includes a pink noise signal to help set a correct reference listening level as per EBU Tech 3343 (paragraph 8.2). The reference listening level signal is available as a separate download as well: 500-2000 Hz monophonic pink noise @ -23 LUFS.

-23 LUFS

Basically EBU R 128 recommends to normalize audio at -23 LUFS ±0.5 LU (±1 LU for live programmes), measured with a relative gate at -10 LU. The metering approach can be used with virtually all material. To make sure meters from different manufacturers provide the same reading, EBU Tech 3341 specifies the 'EBU Mode', which includes a Momentary (400 ms), Short term (3s) and Integrated (from start to stop) meter. Already more than 70 vendors have reported to support 'EBU Mode' in their products.

Implementations

Implementers of 'EBU Mode' can use the EBU R 128 logo. You can download the logo here - these rules of use apply. Many tens of products already support EBU R 128, see the list of implementers supporting EBU R 128 .

Questions

If you have any further questions on EBU R 128 or related topics, which are not listed in our FAQ section, or if you intend to implement EBU R 128 Loudness normalisation in your distribution chain, then please send us an e-mail via: tech@ebu.ch.