Loudness then & Loudness Now - What is Loudness Normalization in the 2020s?
Dynamic range is an important part of music, and compositions come with their loud bits and also their quiet bits. We like the power of a dynamic rock anthem, or something that drives you to dance! Some loudness history ('…don't mention the war…' John Cleese in Fawltey Towers) As the decades went on, this dynamic range became more and more squashed sadly. This was not necessarily for any technical deficiency, but because sonic tastes required it and something called the Loudness War became something entrenched in audio and music society. The origins of the loudness war can be traced as far back as jukeboxes and 45rpm 7"singles. Engineers such as Joe Meek, then working for IBC in London would engage equipment he'd built and techniques he'd invented to ensure that his records were louder than his contemporaries. It worked. More clients came asking for him to make their records. In the analogue world this worked, as far as the reproduction system (amp, speakers etc.) could handle it. Even a touch of analogue distortion is argued to be a wonderful thing. Harmonic distortion can give crunch, bite and a lovely feel. Think about how many plugins there are on sale offering tape saturation for example (an expected necessity to record levels at high signal to noise ratios to rid ourselves of the noise floor inherent on an analogue tape based recorder for example). However it all changed when digital became the norm. No longer was 0dBu the guide level we sort of worked to and the analogue system could be pushed and pushed until something (the tape, or player, amp, or speakers) broke rank and produced unpleasant distortion. No, in the digital world, 0dB became a bulls eye - a target! Each record that was put out was expected to be louder and louder. In essence, compression and limiting techniques were employed over several decades to reduce the difference in level between the loud and the soft moments, so what we'd call the average loudness (VU) would be raised eventually to be as close to the peak (loudest) level as possible. The Loudness War pinnacle sort of happened with Death Magnetic from Metallica. The associated game's audio was not subject to the mastering compression sought by the band. So much so that fans asked for the game version of the audio to be released. However it is not as simple as making things ‘one louder’ (Nigel Tuffnell in Spinal Tap, 1980) anymore! The digital world is changing away from a CD based diet to a streaming one. And at the same time, work by industry (especially broadcast) has started to pick up long-lasting conversations about loudness and have moved standards to what we call
What is loudness normalization?
Loudness normalization has been in circulation for a long time, but has ,relatively recently, been adopted by the streaming services. Essentially, instead of everything aiming for the loudest VU and Peak level as described above, the level of the average loudness would be measured across the duration of the track. For this to work as intended, the playback system (the streaming services) would adjust their level upon playback to compensate for differences in level between two adjacent songs - often delivered over a playlist from two different artists from different studios, different countries and possibly different decades also. So for broadcast they work to -23dB loudness normalisation across their output. This is quite low. In music we're not quite decided yet (I wish the AES would be able to enforce the great work undertaken by Katz et al in 2015). For us at the moment the level is around -14dB… The loudness unit used is called LUFS - Loudness Unit Full Scale, actually loudness levels relative to full scale. Essentially this tells us what the average loudness of the music is across the whole of the song. It's not the peak level (what we used to work to in our old peak meters on Cubase and Logic or whatever), but the bit in the middle. This allows us to insist on a dynamic range (the distance between the average loudness and those peaks). A dynamic range potential of 13dB! Why is it 13dB and not 14? Well it's because we ought to be aiming for a true peak (TP) maximum of -1dB! How do you test for your track's loudness? Well there are some good tools from MeterPlugs and also MusicTester you can check your music in and consider the levels. They express the levels of your music based on the loudness level (LUFS) and also the 'penalty' of placing a loud track onto a streaming site. What's the ideal level? Technically we ought to be mastering your music to -14LUFS and -1dB True Peak, and if this were always possible then your music would be approximately perform best on all platforms. However, there is considerable debate around this with many mastering engineers supplying louder than -14LUFS masters. What does MOTTOsound do? We provide both loud masters (akin to CD) masters (not as loud as Death Magnetic we hasten to add), but we also provide Streaming optimised versions as well. However, if the music does not warrant or perform best as a loud version, then perhaps a happy compromise level is produced and supplied. More… There's so much one could read about this topic, and the sands are slowly shifting all the time (so much come back and update). http://www.aes.org/technical/documents/AESTD1004_1_15_10.pdf