Music Technology — EBU R128, the most important audio breakthrough you’ve never heard of

The problem with loudness

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 they would be screechingly loud in comparison to the show you had been watching. 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 everything would seriously mess up the sound. And it 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.

The R128 solution

It took a long time to come to a solution for this problem, but a few years ago the European Broadcasting Union figured it out, and called it 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 make movies seem properly loud, and highly compressed modern music will be played back quieter instead of louder! It 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.

The new measurement standard: LUFS

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. 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 -17 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. See Spotify’s official loudness recommendations for more detail on this.

Measuring your mix

OK, now we know what to aim for, how do we achieve 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 masters and showing the dynamic range in LUFS. If your DAW software has such a built-in tool, use it! Or do a quick online search for one of the many free R128 measurement plugins available, such as the YouLean Loudness Meter.

Once you have installed an R128 analyser, make sure that any mixes you prepare for final release fit into the levels shown above. If in doubt, aim for a target level of -14 LUFS for your music masters and you should be fine.

If you aren’t mastering your own music but are creating mixes to go to be professionally mastered, it is more important than ever that you leave a fair amount of headroom for your mastering engineer to play with, so it’s still useful to check the levels of your final mix. Note: do not use compression on the output bus of your final stereo mix! Also try to aim for your mixes to be a bit lower than the levels recommended above— an average of around -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!