Music Technology — EBU R128, the most important audio breakthrough you’ve never heard of
If you are of a certain age you will remember how it used to be when you were watching a movie on TV and the commercials would come in and suddenly they were screechingly loud in comparison. And how annoying that was… That’s because up until recently broadcast TV and radio measured how loud things were by the loudest peak in the material, and made sure nothing went above the maximum level by the simple expedient of sticking a limiter at the end of their signal chain. This solution sort-of worked for radio stations that were mainly playing pop music, but was dreadful for TV. Big-budget movies need to have a high dynamic range because they have many quiet parts (e.g. conversations between characters) and many loud parts (explosions, engines revving, gunfights etc.). So tightly compressing them would seriously mess up the sound. This had the effective end result that movies on average sounded much quieter than everything else, especially much quieter than the commercials in between.
So although absolute loudness may have been the same, perceived loudness as experienced by the listeners was very different — and very annoying in many cases.
It took a long time to figure out a solution to this problem, but the European Broadcasting Union found one a few years ago, which was named the R128 standard.
R128 is quite simple in concept: instead of measuring the peak level of a piece of content, we measure the average level over time instead. So a commercial or pop song mastered with a very highly compressed sound, and thus a high average level of volume, will register as very loud, whereas a movie or a piece of classical music mastered without strong compression will have more variation in its loudness and thus register as a lower average level of loudness.
This means, in effect, that any broadcast system using the EBU R128 standard will have movies seem properly loud, and highly compressed modern music will be played back quieter instead of louder! This also means that modern pop and rock music that has been massively “maximised” will be broadcast at a quieter level than classic hits of the 70s that have a high dynamic range.
Major British, French, and German broadcasters adopted the R128 standard in 2013 and since then most of the other broadcasters have followed suit, including streaming services such as Spotify and YouTube.
So if you are mastering music for any of these platforms a good understanding of how EBU R128 works is essential. So let’s get into the nitty gritty of it a bit. What’s the level we need to be aiming at, and how do we measure it?
R128 is measured in Loudness Units Full Scale or LUFS. That’s actually more or less the same as what we used to call db, except instead of aiming for a maximum level of 0db, EBU standards aim for a much, much lower average level.
For TV applications the recommended level is -23 LUFS, with a 1 LUFS headroom for error. That’s more or less the same as -24 db. This means that pop music mastered in the last 5 years and designed to be at maximum peak volume at an average level of about -6 db could end up being played back on TV at -18 db quieter! That’s a huge level reduction.
Luckily most music-based systems and Internet streaming systems have adopted a more relaxed attitude. Apple Music and iTunes Soundcheck expects a level of -16 LUFS, and YouTube and Spotify aim for -14 LUFS. That means that even on Spotify a lot of heavily compressed music will be getting automatically reduced by as much as 10 db.
OK, so that’s what we have to aim for, how do we measure that? Luckily many mastering programs now have a tool or plugin that is R128-compatible, for example PreSonus Studio One Pro includes a very useful tool for analysing your mixes and showing the dynamic range in LUFS. If your DAW software has such a built-in tool, use it!
If not, there are several plugins you can choose from. My favourite is TB EBULoudness from ToneBoosters which is very inexpensive, but other free alternatives include dpMeter from TB Pro Audio, MLoudness Analyzer from Melda, and Steinberg’s SLM 128.
Once you have installed one of the above analysers, make sure that any mixes you master for final release fit into the levels shown above. If in doubt, if you are doing music aim for a target level of -14 LUFS and you should be fine.
If you aren’t mastering your own music but are creating mixes to go to be mastered, it is more important than ever that you leave a fair amount headroom for your mastering engineer to play with, so it’s still useful to check the levels of your final mix. Try to aim for your mixes to be a little bit lower than the levels recommended above— an average of -24 LUFS should be safe. You might be surprised at how much lower that is than what you normally use, but it’s a safe choice in case you ever need to supply something for a movie or TV soundtrack.
Good luck with your mastering!