A version of this article originally appeared on Motherboard Brazil.
At the end of May, Spotify made a change to its music files that went unnoticed by almost all of the service’s listeners. What was apparent, however, to sound engineers and studio wizards was that the volume had been reduced on every Spotify-hosted track.
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Using software called Dynameter, this collection of audiophiles took measurements of popular playlists like the Global Top 50 and albums of genres ranging from soul to metal, and discovered that the Spotify catalog had become quieter.
We consider “loudness” to describe the human perception of a rich sound. When you listen to something, therefore, what really counts is the perception of that sound, not the values that are registered on a decibel meter.
It was only in 2011 that the European Broadcasting Union, one of the main broadcasting organizations in the world, established a measurement unit of loudness with the EBU-R128 standard, called LUFS (acronym for Loudness Units relative to Full Scale). It is, in fact, a smarter unit of measure than decibels for understanding human perception of volume.
Unlike RMS, another measure used to determine the average volume of audiovisual productions, LUFS ignores low frequencies, instead focusing on average and high measures above 2 kHz—the most sensitive region for our ears. A scream, for example, carries more volume sensation than a double bass might, although RMS indicates higher numbers for the instrument (and basses weigh heavily with the old measure). This is because the human voice is in the middle region.
LUFS was created to approximate how our hearing works.
What sound engineers have come to realize is that Spotify has reduced the LUFS index of everything on its platform from -11 LUFS to -14 LUFS, a number in line with that of competing musical platforms like YouTube (- 13 LUFS), Tidal (-14 LUFS), and Apple Music (-16 LUFS). In practice, the volume for human ears will be more controlled, and you may not even notice the change.
We reached out to Spotify for comment about the LUFS reduction: “Spotify is always testing new features to benefit its users. Recent changes in the playback experience are part of the aspects we are evaluating.”
So why is this important?
A better sound
Initially, the approval of the EBU-R128 standard was not aimed at streaming platforms and the music world. The intention was to normalize the sound patterns of televised content. You know how some commercials are way louder than others? Or the difference in the volume between a TV program and an ad? The goal of the EBU-R128 standard was to streamline those differences and standardize the volume of TV channels.
One of the main techniques for boosting the volume perception of a song is through compression. It can be performed with specific hardware or programs during the mastering process. As the name implies, the technique compresses the sound wave. This places a ceiling on the waves’ peaks while promoting the gain in the lower parts. Imagine taking an electrocardiogram and tightening those gauges so that the higher and lower parts are more level.
“While trying to boost the sound, they ended up sacrificing its quality.”
“If you compress an orchestra, and the violinist is playing a smooth violin by himself, you’re going to hear it loudly,” explains Pedro Luce, a Brazilian music producer. “When the rest of the musicians come in with their instruments, you’ll hear everything with the same intensity.” The compression intensifies the calmest, emptiest moments of the song.
You see the problem, right? A song is made of quieter and more agitated moments. In real life, a guitar alone doesn’t have the same intensity as when the drums join in. When compression occurs in an exaggerated way, it makes everything louder, which ends up stealing the dynamics away from the music itself. It’s like listening to that one loud friend of yours who always yells when they’re drunk. In addition to being bothersome, it also becomes monotonous after awhile.
“In national (Brazilian) production, there are [musical styles] that abuse the use of compression,” producer Nando Costa told me. “In country music, which includes mainstream artists, there’s many productions and mixes that are thoroughly distorted. You hear the sound of the muffled voice. The drums seem like the performer is playing with a toothpick. This is all a result of very compressed and limited audio. While trying to boost the sound, they end up sacrificing its quality.”
Even with this knowledge, producers, artists, and record companies prefer to bet on loud sound that’s full of compression. Among other concerns, there’s the thought that a sound stands out more in comparison with the work of other artists when it’s louder. Sadly, for most untrained ears, loudness is mistaken for a sign of quality. The dispute to see which artists created the loudest songs initiated the “Loudness Wars.”
The race for the highest volume started in tandem with the emergence of the digital age of music, back when CDs became the main form of sound distribution. Prior to that, when vinyl reigned, there were physical limitations that ensured the compression wouldn’t become muddy; a record that produced loud enough sounds could make the needle jump, which would ruin the entire musical experience. Those limits ended with the dawn of the CD. It was as if a road with no speed limits had been paved, and compression gained even more traction.
Moreover, in the vinyl era, it was normal to listen to an entire album by the same artist. The immediate comparison between works from different records and different artists did not exist, so there was no need to make one track stand out from the other by volume. This practice began to fade with the introduction of the CD, which made it easier to change the disc on the stereo, and went even further with MP3 players, which introduced the option to play songs on shuffle. Nowadays, in the era of playlists, it’s difficult to find people who listen to two songs by the same artist back to back. As a result, produced music has become compressed and louder. Check out a chart generated by the site Sample Magic.
To make matters worse, lack of momentum isn’t the only side effect of excessive compression. When you enforce boundaries on a sound wave, you create distortions in the actual waves, which can create distortions in the music. “The more the compressor works, the more it will cause distortion in the music,” explains Costa.
One of the records that symbolizes just how far a band will go to boost compression in order to gain volume is Metallica’s Death Magnetic. At the time of its release in 2008, many fans complained about the sound madness found on the disc: There were no auditory dynamics and many moments of pure distortion. Months later, the band released the game Guitar Hero: Metallica, which featured remastered, quieter versions of the same songs which, within the game, had to compete with other Metallica songs from other albums.
Researchers at the University Hospital of Copenhagen, the Technical University of Denmark, and the University of Aalborg published a study comparing the two versions of the album. Below, you can see the comparison of a 30-second stretch of the song “My Apocalypse.” Notice how the band managed to achieve the so-called “brick wall compression,” a track of sound with no dynamics whatsoever.
By reducing the LUFS index, Spotify is telling the music industry that there’s no use in trying to sound louder than everyone else. Everything that comes into the platform will sound and be on the same level. Even if something is mastered very loudly, the volume will be automatically reduced. Of course, this serves to standardize the streaming service as TV channels previously had done with their commercials, but apart from benefiting the service itself, Spotify will force the industry to work differently. The songs will have to draw attention to other aspects that go beyond the volume. The door to more dynamic sounds is wide open.
“If you have a very compressed audio, it will get smaller because of the lack of dynamics,” explains Costa. “When you lower the loudness of that sound, you have the feeling that it plays much lower.”
In other words, the songs with loudness above -14 LUFS sounds lower on Spotify compared to those that have been compressed below the magic number. Nando Costa makes this comparison in the video below: A national artist mastered around -13 LUFS and a Metallica song from Death Magnetic (watch from 40:30). At the time of the video, Spotify’s standardization standard was still -11 LUFS and the music had not been mastered specifically for the platform, however, the result of the national artist was much better than that of the elderly metalheads.
On this site, you can graphically see what happens when a very loud song has its volume reduced when entering Spotify.
“Sometimes the music is not bad just because of the composition, but by the way it is presented,” says Costa. Thus, Spotify may help bring an end to Loudness Wars, which should generate better quality music in general, with more dynamics and cleaner audio.
But that’s not the only result of Spotify’s new volume regulation.
Protect Your Ears
Are you familiar with the sense of relief that sometimes comes when we stop listening to music and indulge in peace and silence? It happens even to people who can’t get enough of their music, and it’s associated with a phenomenon called “listener fatigue” (or ear fatigue).
“The effects of [listener] fatigue are well known, although people do not always link these effects with the term fatigue,” said Dr. Tanit Ganz Sanchez, an associate professor at the School of Medicine at the University of São Paulo (FMUSP) and founder of the Ganz Sanches Institute, a facility that specializes in hearing treatment.
Symptoms include actual fatigue, irritability, and insomnia.
Sanchez explains that we have a small muscle whose function is to protect our hearing, called the stapedius. The function of this organ is to bar the entrance of very aggressive sounds in our ears. It tightens the eardrum and functions as a filter so that the sounds get softer before they’re perceived by the middle ear, a portion of the auditory system that leads the sound to the inner ear, where we actually hear. The problem is that prolonged exposures to intense volumes can cause fatigue in this muscle.
“I’m comparing the stapedius muscle with the arm muscle,” she explains. “Let’s say you spend half an hour pumping iron in the gym. At some point, that muscle will say ‘ Enough, no more.’ The ear muscle also has this contraction, but we have no power over it. It’s involuntary and happens whenever you hear a louder sound. If you listen to loud music often, that muscle will become wearier.”
The only difference between the stapedius and the bicep is that we rarely actually feel any pain in the ear, like the pain caused by a day of over-lifting in the gym.
In this way, by putting a ceiling on the LUFS, Spotify is contributing to the health of its customers’ ears. It’s worth remembering that Apple has already been sued by people who lost their hearing after excessive listening on the iPod.
“From a medical point of view, the loudness reduction is wonderful,” says Sanchez.
