Spotify uses a loudness reference for normalising the loudness of a track. This way the tracks played in Spotify will sound more or less even in loudness.
According to their website:
Negative gain is applied to louder masters so the loudness level is at ca – 14 dB LUFS. This process only decreases the volume in comparison to the master; no additional distortion occurs.
Positive gain is applied to softer masters so that the loudness level is at ca – 14 dB LUFS. A limiter is also applied, set to engage at -1 dB (sample values), with a 5 ms attack time and a 100 ms decay time. This will prevent any distortion or clipping from soft but dynamic tracks.What is loudness normalization and why is it used?
Errr!!! You either use dB’s for measurements or LUFS, but combining the two like Spotify does ‘- 14 dB LUFS’ is not right!
Three loudness norms
This -14 LUFS norm is just one part of the story because Spotify uses not one but three (!) settings for loudness: Quiet, Normal and Loud. You can change this under Settings > Volume level:
You can also disable Normalize volume. No loudness normalisation is applied to the music when using this setting.
Loud – equalling ca -11 dB LUFS (+6 dB gain multiplied to ReplayGain)
Normal (default) – equalling ca -14 dB LUFS (+3 dB gain multiplied to ReplayGain)
Quiet – equalling ca – 23 dB LUFS (-5 dB gain multiplied to ReplayGain)Can users adjust the levels of my music?
Notice that under Loud and Normal gain is added. Under these settings tracks will be set to a higher level when they are too soft.
Spotify will use a limiter on soft tracks
Anything lower than -11 LUFS or -14 LUFS will be pushed in volume depending on the settings (Loud or Normal). Only when the end-user uses the Quiet setting the music will only be lowered in volume but never be raised.
When tracks are raised in volume a limiter is applied. And this limiter, I found out, sounds shitty.
Listen to this:
Let’s listen to this piece of Mahler:
Using the Normal setting you hear the limiter kick in which makes the violins to sound “nervous”.
I decided to sample this fragment using the four possible settings. First fragment: Normalize OFF. Second: Quiet. Third: Normal. Forth: Loud.
Notice how terrible Normal and Loud sounds?
Is there a solution to this? Not really because the problem in this case is caused by Spotify. Offering the end-user these Normal and Loud settings which sound like shit was not a bright idea.
It might be a better idea for Spotify to stop using a limiter and only lower the volume when needed but never raise it. Tidal and YouTube are two examples I know who will not increase the volume. Spotify should follow this norm, simply as that.
Most mastering engineers ignore these target loudness norms. Some streaming service might change the volume level of your track and might even apply a bad sounding limiter to it. Hate it. But well… so what?