Streaming platforms and loudness normalising
Streaming platforms are the future. However, freedom to compile playlists of anything you like comes with a problem: the industry’s failure to standardise over the years means that music from different eras or genres could end up with dramatically different loudness levels.
Streaming platforms therefore use loudness normalising, so playback levels for each file are adjusted to match a target. Unfortunately, they all use different methods to analyse loudness – only Tidal currently uses BS.1770 standards.
Fortunately, there’s now an easy way to check what will happen to your master on each platform: mastering engineer Ian Shepherd has teamed up with Meterplugs in order to create www.loudnesspenalty.com.
Simply drag in your mastered file in any format, and the site will then calculate the ‘loudness penalty’ for each platform. This is the amount by which your file will be adjusted in level on playback.
If your ‘optimum loudness’ version gets all negative values, you’re golden: this means it’s already louder than the target, so is being adjusted downwards to compensate, and there’s no point making it any louder.
If you see positive values, however, this means your master is quieter than the target. Most platforms will turn these files up, but only until they clip: if your file is really dynamic, there might not be enough headroom for it to reach the target. Notable exceptions are YouTube and Tidal, which only turn down loud songs, and Spotify, which we’ll come to in a moment.
So far, none of this has changed the sound of the audio at all. The normalisation simply adjusts the overall playback level of your song, with no dynamic compression or limiting.
Spotify is different: it will turn up your audio to match its target, and will limit peaks if necessary. This, of course, has the potential to significantly change the sound of your master.
With Spotify being the biggest music streaming platform, this is the one that’s most likely to need its own specific master. This means you can judge and hone the extra limiting required, rather then leaving it to Spotify’s generic limiter algorithm.
However, bear in mind that, until recently, this problem was much worse. Spotify used to have the highest target loudness of all the platforms – around -11 LUFS – but this has now dropped to -14 LUFS instead. A song mastered specifically to match their old specs would now be playing back with 3dB of headroom that could have been used for extra transient punch.
The most recent change gave premium users a choice of three target loudness settings. Most users will probably leave this set to ‘normal’; however, audiophiles who know the difference will hopefully change it to ‘quiet’, so it’s probably best to just make your master sound as good as possible, and don’t compromise quality to meet a target loudness.