Loudness Radar accuracy

[Richard Knight]

Loudness metering is a lot more complicated than VU or PPM, all the loudness meters have psychoacoustic algorithms to try and duplicate what the ear/brain combination perceives as ‘loudness’
Here in the UK broadcast loudness has been standardised at -23db as read on a loudness meter. Even with this setting depending on how it is broadcast the levels of even the same programme can be different at home. A programme broadcast on SD will have a PCM soundtrack with no dianorm meta data, but the same soundtrack on HD will have a Dolby Digital soundtrack and will have the -23 dianorm setting and will be 10db quieter at home if the home receiver can read this metadata. It seems until the home receivers are standardised there will always be variations of levels.
If you import a Dolby Digital file into Premiere it will change its level depending on the dianorm setting, it will appear quieter than you exported it.