Ian Shepherd On Loudness & Dynamics

Ian Shepherd, mastering engineer.Photo: Mike Banks

It’s nearly a decade since the LUFS standard for loudness measurement was defined, yet many still seem confused about what it means for music production.

Back in SOS February 2014, we devoted 12 pages to explaining the then‑new ITU‑R BS.1770 audio loudness measurement/normalisation standards. At the time, it was clear they’d have a huge impact on broadcast audio, yet questions remained about what they would mean for music production. Since then, YouTube and most music streaming services have implemented loudness normalisation, and software tools to measure loudness have become readily available, even been built into our DAWs. Plenty of confusion remains, though, about what loudness normalisation algorithms do, how loud is loud enough for music, and how and when to make good, practical use of LUFS meters. Furthermore, there remain plenty of sceptical engineers and some, for various reasons, who continue to use clipping and heavy limiting to master loud.

With these thoughts in mind, I figured it was time SOS revisited the topic. We’ve written about the theory a number of times, but I wanted to find out how things have been evolving in practice, and to tease out some good, practical tips and advice for our readers. To that end, I enjoyed a long, detailed chat over Zoom with UK‑based professional mastering engineer Ian Shepherd. Ian has long been a fierce and (since his critique of Metallica’s Death Magnetic back in 2008) prominent critic of over‑limiting in pursuit of loudness, campaigning for people always to aim for musicality first. If you’re sceptical about these ideas, I’d urge you to hold your fire and approach Ian’s words with an open mind. It soon became abundantly clear to me that he’s not opposed to creating loud masters per se; his message is more nuanced. And whatever your view on the question of ‘how loud is too loud’, one thing’s certain: Ian knows a hell of a lot about how best to use those loudness meters, and how your mixes will fare when played over the various streaming services!

Hearts, Minds & Language

I wanted to know, with loudness normalisation now enabled on YouTube and so many streaming services, whether Ian believes that the ‘loudness war’ has genuinely been ‘won’, as we suggested it might have been back in 2014. “The funny answer,” he joked, “is to say yes, I think the war has been won but someone needs to tell the generals!” Setting humour aside, though, he struck a less triumphant tone: “The reality is that no, it hasn’t been won. It’s basically a done deal as far as the technology, the standards and the best practice are concerned — but it’s now a battle for the hearts and minds of artists and engineers. That’s definitely not been won.

“With hindsight, I used lots of language in the early days of the loudness wars debate and Dynamic Range Day [see box] that I’ve now come to regret. People felt I was blaming them, and they felt criticised, which was never my intention. While it achieved what I wanted in terms of raising the profile of the issue, there are more positive ways that I could have presented the information.”

It’s perhaps no surprise, then, that he takes a different tack today. “What I’ve found most effective is the plug‑ins and the Loudness Penalty site [see box]: rather than just present people with facts, or even try to win over their hearts and minds, I’m just giving them the tools. It’s much, much more impactful if people can hear for themselves the difference between their master at ‑4 and ‑10 LUFS when they preview it at ‑14 in Loudness Penalty. That’s the ‘Aha!’ lightbulb moment.”

Ian also offered an insight as to why people might feel the need to compete on loudness. “By my estimation, somewhere between 80 and 90 percent of people who are listening online or on devices are listening to normalised music. But when I surveyed engineers and musicians on social media, 75 percent said they turned normalisation off because they want to hear the music exactly as it was mastered. So there’s this really cruel irony that the people who care most about the audio are listening in a way that almost nobody else hears it, and because of that they feel they need to match [the loudness of] all the other stuff that’s out there — but nobody else cares!”

Meter M’aide!

Do you know what to make of the different readings on a loudness meter? Ian suggests that Short Term LUFS might be the most useful when mixing and mastering.While we were on the subject of tools and communication, we discussed loudness meters. I’ve long thought that with so many readings, loudness meters can seem a bit confusing. The True Peak function might seem obvious, and most of us appreciate that Integrated LUFS indicates a track’s loudness and is used by streaming services to normalise playback loudness; but what of Momentary and Short Term LUFS? I asked Ian how he uses these, and whether either could be seen as a substitute for VU or RMS meters.

“LUFS is a remarkably effective measurement. It agrees with my ears a lot of the time and works well with something like 90 percent of material. But yes, it can also seem very confusing. They’re not intuitive names. I think lots of people understand RMS, though, and LUFS is basically a more sophisticated version of RMS. Short Term LUFS and RMS are often virtually identical, which I think is helpful to know. I still use a VU meter, too, because there are important things about them that aren’t replicated in most loudness meters. The scale goes from, what, ‑30 to +3 dB and it’s vastly more sensitive around the zero point. So if you push even slightly too high it pegs, and if you go 3‑4 dB lower than zero the needle really drops. It’s not a target (I don’t want people to aim for targets!) but in terms of using it as a reference you can see really easily where you are, whereas a lot of loudness meters aren’t so easy to read. If you’re happy with RMS and happy with VU, keep them, and just look at the Integrated loudness when you’re done. The biggest problem with VU meters is that they’re overly sensitive to bass, so if you’re working on anything that’s got huge bass in it... the meter will peg whenever you get to the drop. That’s a situation where you might find it more helpful to use LUFS Short Term.”

Having said all that, Ian was keen to clarify that: “I don’t watch the loudness meter when I work; I just check it afterwards. My simple advice to everyone when mastering is to make the loudest sections of your music consistent in terms of Short Term LUFS. Decide how loud you want the loudest bits to be, and get those to a consistent loudness. I would recommend no higher than ‑10 LUFS Short Term, and then simply balance everything else musically by ear. I’m talking about mastering, but it’s just a reference point — you can do the same thing when you’re mixing, making the loudest sections, say, ‑16 or ‑18, so you have plenty of peak...