Why Loudness Meters Are Useful

It has been described as ‘a true audio levelling revolution’. Recommended because of its simplicity and potential quality gains, loudness-levelling standards are now being introduced around the globe. These standards for loudness correction have been introduced as a consequence of “The Loudness War”, a debate that has been going on in the audio industry for decades. In the quest for fidelity over volume, Loudness Meters are now an integral addition to the arsenal of audio professionals submitting content to streaming and broadcasting platforms - but why?

The Loudness War

It all started in the 1960s. Loudness became a competitive weapon in the sonic arms race to get songs aired on the radio. Vinyl 45s were the medium of the time. Labels and producers would request cutters to create deeper grooves resulting in louder recordings so that when label or radio bosses were sifting through mountains of demos, theirs would stand out from the crowd. This transcended into adverts that were created louder to get marketing messages across. Of course, with producers constantly trying to one-up each other, recordings got louder and louder.

This trend continued well into the 1990s and 2000s when CDs came around. Digital presented even more options for producers to rinse loudness levels through a process called “dynamic compression”. This process applies varying levels of gain over a recording to fit the level within a minimum and maximum range often via digital brick wall limiters. It makes music sound more “compact”, squeezing every ounce of loudness out of a piece of audio whilst keeping it within a reasonable volume range. Many, but not all, audio professionals argue that the pursuit of loudness has had a deleterious impact on audio, making it sound less natural and spoiling potentially great music – hence the “loudness war”. This is illustrated well in this video.

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This infograph from Twitter user @iamreddave illustrates the increasing levels of loudness over the decades using data from the http://dr.loudness-war.info/ 

Loudness Issues in Broadcasting

Issues with loudness and audio are ranked amongst the most pervasive problems in the broadcasting industry. We are all too familiar with the situation where you are watching a programme, only to have to grab the remote and adjust the volume when adverts or a new programme comes on. It’s down to variations in how different producers perceive loudness.

Fortunately, those days are almost behind us. National TV and radio broadcasters, like the BBC and Channel 4, were the first to take note of viewer complaints about noise variations between programmes and adopt loudness standards such as Europe’s EBU-R128 and America’s ATSC A85. Initiatives such as the CALM act regulating advertisement volume have also helped enforced loudness regulations. However, it wasn’t until digital services like Netflix, YouTube, Apple, and Spotify voluntarily implemented their own loudness standards that acceptance of loudness standards has become ubiquitous (This conversation can be traced back through a reddit thread by Bob Katz + co back in 2016). Nowadays, if the audio you produce doesn’t meet the loudness delivery spec of the platform you’re delivering to, then it is rejected or automatically altered by the platforms normalisation algorithm.

The Power of Dynamics

The penchant for “louder is better” was generally a decision based on commercial competitiveness rather than one of artistic sensibility. Compressing audio to make it sound louder sacrifices dynamics which many listeners find more harmonised, defined and of better quality. Funnily enough, the more dynamic audio is, the louder it is also perceived. Like a classical music composition building a crescendo or a firework ascending to its big moment, quiet moments give rise to loud moments and both work in tandem to create interesting audio that gives off emotion and takes the listener through a journey. 

New Standards & Measurement of Loudness: LUFS

All loudness standards, such as EBU-R128 and ATSC A/85 are based on ITU BS.1770. This is an algorithm formulated by ITU to measure audio programme loudness and true-peak audio level in a way that agrees more closely with how humans’ subjective sense of loudness. In other words, BS.1770 is a well-researched attempt to correlate our subjective perceptions of loudness with objective physical changes in amplitude.

 In addition, for these new standards, a new common measurement of loudness was required. Enter LUFS, which stands for Loudness Units Relative to Full Scale. LUFS are exactly the same thing a LKFS. This measurement was introduced by ITU in EBU-R128. The concept of a Loudness Unit (LU) is the same a Decibel. However, LUs differ to Decibels in that decibels are a measurement of the level of air pressure generated by sound, whereas LUs are weighted to the real perception of audio and allow the measurement of loudness without a reference. LUFS closely resemble the way that human ears perceive loudness.

Introducing LUFS, the measurement and loudness standards has helped strengthen and spread the loudness-levelling concept and eliminate the competition for loudness, returning audio back to an artistic process. Dynamic compression is once again an artistic tool and not a loudness weapon. What is more, once basic loudness levels are set for audio signals in the foreground, like narration and opening music, then it comes back down to mixing by ear, allowing the producer the liberation to show his craft. Everybody wins.

What is True-Peak?

It is becoming widely accepted practice to standardize the true-peak levels of all audio.  When digital audio is converted to an analogue signal that can be played through speakers, part of this conversion involves applying a reconstruction filter to round off stepped digital signals. Rather than just relying on the maximum level of digital samples, True Peak level is a measure of how far an analog signal gets considering the maximum level of the underlying analog signal. A true peak meter displays the absolute peak of an audio’s waveform as it will be heard once the digital audio has been converted to an analogue signal that can be played through speakers. Without this insight, it is likely that the audio you master be clipped once the signal is converted from digital to analogue (unless you have very well trained ears). In any case, meters with true-peak readings offer some peace of mind. True Peak Limiters, such as the one that comes with the Bute Loundess Suite, offer a solution to meet true peak targets and avoid unnecessary clipping, distorion and the need for re-editing.

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Are Loudness Standards For Everyone?

Not necessarily. In the music industry, loudness standards are recommendations rather then regulation (however, as discussed earlier platforms like Spotify and Apple do have their own guidelines and normalisation algorithms). It is worth remembering that there has been shown by Earl Vickers at the Audio Engineering Society convention that there is no measurable impact of loudness on record sales (http://www.sfxmachine.com/docs/loudnesswar/). If you want to be a professional and see dynamic and consistent audio, loudness standards are something that you should consider. In some contexts, such as playing dance music in a club or if you want a distorted sound, then dynamic compression can be a favourable technique. There is a trade-off here between quality and loudness. If you are a music producer, the thing to remember is that if you submit mastered tracks to streaming platforms and you haven’t used a loudness tool to check and correct your audio hits the delivery spec, then there’s a good chance your hard work will be altered and the finished track won’t be heard like you intended it to.

In the case of producers working in game audio, loudness delivery specs help keep things consistent. There is so much dialogue and SFX going on in games, that working to a loudness spec becomes a useful code of practice to optimise the experience for gamers. For example, you don’t want background music to clout dialogue, or gun shots to deafen gamers. When you are working with dialogue and localisation, you also have to considered ranges in the volume of different voice actors - the BUTE Batch Processor is a good solution for ensuring vast databases of dialogue are consistent in loudness.

In broadcasting, film, radio and TV, loudness solutions are an absolute must. Broadcasters will reject a program if it doesn’t strictly adhere to the loudness delivery spec of the country they are broadcasting in. Like in gaming, tools like our Bute Loudness Analyser are great for giving you the information you need to mix all the different elements of a TV show, film or documentary whilst adhering to spec. Our BUTE Loudness Normaliser is great for a final check, and Limiters, like the one included in the BUTE Loudness Suite, are useful for catching any true peak overshoots giving you confidence that you won’t have to go back and re-master your audio. 

So why do I need a loudness meter?

It is important to remember that the concept of loudness can be deceptive because loudness is not a discrete physical property of sound, but rather how we humans perceive the strength of sound. It’s psychological as much as it is physical. Here are a few reasons that loudness meters are a useful aid for professional mixing and mastering engineers.

Firstly, meters are an invaluable aid.

Whilst many experienced engineers will prefer to mix by ear, loudness meters are a valuable aid and take out some guesswork during production. Over-reliance on numerical insights can be detrimental to creativeness, but when you are required to meet regulations a loudness meter can mean the difference in having to re-edit your work. Graphical meters, such as our Bute Loudness Analyser, are a very useful aid for all you budding professionals looking to train your ears and experienced producers needing the information at hand to ensure they are complying to loudness standards.

Secondly, meeting standards is often about preserving quality and ensuring your audio is heard as intended.

For major publications like the BBC or Netflix, complying with loudness standards is a strict regulation because viewers expect the best. Good loudness meters will allow you to export a log of the loudness levels of your audio to submit with your work to prove adherence. In the case of online publications, loudness regulations are more guidelines than subject to strict adherence in this case. It is about being aware of loudness algorithms within platforms. The likes of Spotify, YouTube, Apple automatically normalize your audio to fit in with their standards, so audio that is louder than a platform allows will be trimmed and reduced in volume. If you want your audio to be heard as you intend it, then a good meter with the right pre-sets will ensure this. The Bute Loudness Analyser offers all the necessary presets to help you fit in with the range of loudness recommendations you’ll come across.

Thirdly, if you are a broadcaster or post-production engineer dealing with a high demand for output, then you want the tools to help you speed up your output.

Whilst mixing and mastering by ear allows you to add finesse to your audio, not every piece of content require a lot of time to be spent at this stage of the production process. Bute’s interface has been cleverly designed to be intuitive and in tune with your workflow so you spend less time meeting loudness standards.

Russell McMahon