Two supports for music with two different evolutions.
Let’s start with the oldest of the two, the CD.
CDs have arrived in December 1982 (March 1983 in France) with as argument a better dynamic (90 dB), no surface noise compared to the vinyl. The CD ended up dominating the market from 1988. The loudnesswar starts in the 1990’s and have explosed since the 2000’s on the new releases and the remastered album.
The loudness war started by setting the albums to the maximum level of the CD, that is 0 dB (in digital, 0 dB is the maximum level that cannot be exceeded, the lower level is indicated by a negative value), and it is not possible to go higher. To give more the notion of volume, the compression is used. Compression allowed the average level to be raised by several dB.
Fortunately, music styles such as jazz and classical will be a little or not impacted. Today, the argument of the dynamics of the CD compared to vinyl has been reversed with the compression of the CD. Vinyl is more dynamic than compressed CD.
In the mid-2000s the first audio streaming offers have appeared. The sound was compressed in MP3 and then in AAC. This offer has developed and exploded from the 2010s, to exceed CD sales since 2015.
Streaming has also evolved in quality with lossless offers (Flac format for example) to offer the same quality than the CD. These offers have been followed by high resolution offers up to 24 bits 192 kHz ( vs 16 bits 44.1kHz CD).
Then, streaming services have also be affected by loudnesswar, but the services reacted and imposed a standard with average reference level of a track. If a track is above this level, it has be automatically lowered, it is the “Loudness normalization“.
For this, they relied on LUFS (Loudness Unit Full Scale, ref : EBU R128) or LKFS (Loudness, K-weighted, relative to full scale, ref ITU 1770 R2LB) is a standard to mesure the integrated loudness of a track.
We also use the Max True Peak value which indicates the maximum level of the real recording after conversion by the DAC. In fact the Max True Peak can be higher than 0 dB, unlike the Max Peak which is the maximum level of the digital file values.
How is this possible? During the conversion, the converter interpolates between 2 samples to generate the analog signal. So even if a sample does not exceed 0dB, the conversion can exceed 0 dB and creates distortion.
The diagram below shows an example of interpolation.
The Sample Peak is at -4 dB, and the Max True Peak is at -2 dB, i.e. 2 dB above.
For this reason, the Max True Peak is now used, this is the most exact measurement.
Concerning the level alignment, a song with integrated loudness at -14 LUFS stays at -14 LUFS.
If a song has a level at -8 LUFS, it is reduced by 6 dB to -14 LUFS. In the example, the song with a starting level at -8 LUFS is rendered with the same perceptual loudness, but it is less dynamic.
The sound engineers have adapted and now they make a mastering dedicated to streaming. It is different for the CD which doesn’t apply this standard.
And if the level is below at -14 LUFS, it depends on the streaming services, some increase the level, others like Amazon Music do not change the level, which allows to have a very dynamic recording. The lowest accepted by Amazon Music level is -19 LUFS.
Below there are some value indications from the Streaming Services:
|Max Integrated||Max True Peak||Ref|
|Amazon Music||–14 LUFS||-2dB||Link|
|Apple Music||-17 to -15 LUFS||-1 dB||Link|
|Spotify||–14 LUFS||-1 dB||Link|
|Deezer||–15 LUFS||-1 dB|
In addition to the tested formats, 2 reviews have been updated with the streaming version of the album :
For the first two, the CD is much less dynamic than the Streaming version (Album of 2021, 2020, 2011), Streaming gives a more enjoyable version to listen, but only for Dolby Atmos ou 360RA releases. For Dolby Atmos, the standard imposes an integrated LUFS level of -18 dB (+- 2 dB).
- Taylor Swift – RED (Taylor’s Version) (2021) for the streaming Dolby Atmos only, link
- Alicia Keys – Alicia (2020) for the streaming 360RA only link
For Brother In Arms by Dire Straits, the Streaming has a similar dynamic than the original 1985 CD, but does better than the remastered 2000 CD.
- Dire Straits – Brothers In Arms (1995), link
We cannot generalize with 2 examples, but one thing is certain, the masters of the new albums take into consideration the streaming and allow to have a better result than the CD which always remains in the loudness war and stays inferior to the listening. Streaming has succeeded in setting up a standard to stop loudness war, but only for spatial sound.