While many people were relaxing and celebrating over the Christmas and New Year's period, various Members of the EBU Loudness Group 'P/LOUD' spent their colleagues' and own time performing subjective evaluations of loudness gating methods. The resulting data were presented last week, at the sixth P/LOUD meeting in Vienna.
| Adding a gate to the ITU BS.1770 metering specification is meant to leave out the quiet parts of a programme that would otherwise lead to too low a measurement. At the P/LOUD meeting Japanes broadcaster NHK confirmed with new test results that it is necessary to take into account the effect of the gating function on the measured loudness when determining the reference loudness level. As a rough guideline the EBU Group had already been considering relative gating to increase the loudness measurement by typically 1 Loudness Unit (LU). This was confirmed in NHK's tests. Another question was if adding a gate which is relative to the loudness level significantly improves the loudness measurement compared to the use of an absolute or iterative gate. The P/LOUD Groups' subjective tests indicate this is indeed the case for higher gating thresholds. The Group will now look at what gating level to specify. |  Richard van Everdingen (DBLC), presenting the results of the P/LOUD subgroup on distribution. |
Manufacturers support 'EBU mode'
Other good news came from the meter manufacturers in the group which held a dedicated subgroup meeting to discuss common requirements for loudness meters. The main result of that work (besides a detailed list of important meter specifications) was the commitment of the manufacturers to support a so called 'EBU mode' in their products. This means audio engineers can be confident that when they switch their meter to EBU mode, they will be measuring the same way as any colleague with another EBU-mode-enabled meter. There will of course be enough freedom left for the industry to compete on other features, such as on how to display the measurements.
The coming weeks P/LOUD will focus on creating Practical Guidelines, taking into account the mixing experiences of several P/LOUD Members who are already mixing to the draft specification. Such as Germany's NDR, which has shifted to loudness metering and normalisation with much success. Others plan to follow later this year, when the complete specs are ready. The next P/LOUD meeting (mid March) may become the last one. In which case a thorny topic has been addressed in record time. But let's not shout too loud about that yet ....