Not sure what all this loudness stuff is about and how it affects you? Confused about the difference between LKFS and LUFS? In this six-part series, loudness expert Mike Thornton answers all these questions and many more in his premium tutorial series, which is now available for free.

Why Is It Now Available For Free?

This series, originally released in 2016, was on our premium tutorial channel, and since the platform they were hosted on closed down, this much-loved resource has not been available. Rather than find another platform, Mike has decided to make the entire course available completely free. We will be releasing the complete series over the coming weeks, all of which you can access completely free.

In just over 1 hour, Mike Thornton helps you understand how the new loudness standards affect you and the clients you work for. Mike has been delivering loudness training courses to broadcasters in the UK, Europe and further afield, and with this tutorial series, you too can benefit from his expertise.

Who is this course for? 
Although it is aimed at people working in broadcast and OTT environments, they need to produce content to comply with the loudness delivery specifications like ATSC A/85 for the US and Canada and EBU R128 for Europe, including live audio mixers, audio post-production editors and mixers, compliance teams, as well as video editors, and others working in the delivery of broadcast content, the first three tutorials in the course will be very helpful for people working in music production, who need to deliver loudness compliant mixes to any service using loudness normalisation.

What does the course cover?
In this series, we start by answering the question, ‘Why do we need loudness?’ We go on to cover the difference between peak level normalisation and loudness normalisation. We look at the history of audio metering and how the loudness standard has been developed and learn that the different delivery specifications around the world are, in fact, all based on that one standard. We show how to calibrate your monitor speakers, which is an essential part of mixing to loudness, before moving on to some tips and tricks on how to mix to comply with the new loudness standard and delivery specifications. 

How Much Does This Tutorial Series Cost?
This course was available for rent on our premium tutorial channel and cost $49.99 for one year. It is now available completely free at no cost.

Why Do We Need Loudness?

Whether it’s music production or audio post-production, many people have asked why they cannot carry on doing what they have always done. Surely everything is fine?

Well, perhaps not.

In music production, we have experienced the loudness wars, as producers and engineers tried to make their music track louder than any other track, with the resulting annihilation of dynamic range.

When it came to broadcasting, loudness-related issues represented a significant number of complaints received by broadcasters. For example, looking at one 40 day period here in the UK, BBC TV received 100 complaints relating to loudness issues.

• 61 related to the background sound was too high, which is an issue of intelligibility.

• 20 were about volume jumps between content, where program trailers or announcements were louder than the content around them. On commercial TV channels, the biggest issue was with adverts and trailers being much louder than the programs around them.

• 19 were about the volume range within programs being too high, which often relates to the dialogue being quiet and indistinct, and then the music kicks in, and suddenly, everything gets much louder.

In addition, when viewers change the channel the volume could often change. All of this means that overall loudness has become a serious issue for consumers.

With the introduction of music streaming services, most decided to normalise their catalogues to loudness rather than peak level, but unlike broadcast services, there is a significant range of delivery specifications across the different streaming providers.

Before we go any further, we need to start by looking at what loudness is and how we perceive loudness.

What Is Loudness?

Loudness is the perceived strength of a piece of audio, how loud we perceive it to be and this can depend on level, frequency, content and duration. It’s not just about level.

Level is an electrical measurement of the audio signal, whether it’s analogue or digital.

To understand loudness we need to take a look at how our ear works.

Firstly, the ear-brain combination does not register all frequencies in the audible spectrum equally. For example, lower-pitched sounds require more energy into the eardrum if it is to be perceived as being equally loud as mid-range speech frequencies.

This is not news, back in the 1930s research was undertaken by Fletcher and Munson from listening tests and these curves were drawn up from the results…

Secondly, although our ears react to changes in level pretty quickly, our brain does not register a change in “loudness” unless the level change persists for at least 400ms.

The History Of Audio Metering

The earliest way we measured loudness was to measure the RMS value of an audio signal, mainly using an analogue VU meter. The dynamics of the VU (Volume Unit) meter proved to be a remarkably close approximation to the perceived loudness of the audio being measured.

So, why did we ever choose to measure Peak Level rather than RMS in broadcasting?

In the late 1930s, as radio broadcasting was being established worldwide, there was a real need for a reliable meter to display the signal being sent to the transmitter. The BBC developed their peak program meter (PPM) in the UK. At around the same time, the German broadcasters were undertaking similar research, but because of the timing, they could not collaborate with the BBC, they, too, developed a similar peak reading meter.

When we moved to a hybrid analogue-digital world, we set our reference so that we had around 10dB of headroom above our maximum peak audio level.

Because of all the history since the very early days of radio, the delivery specifications from broadcasters were built around peak level. This resulted in everyone matching (or normalising) programmes to a matching peak level, usually around -9 or -10dBFS.

To help make things sound louder but remain in spec, audio compression techniques, similar to what happened in music production, were developed to make content louder without increasing the maximum peak level, with the end result that we experienced loudness wars in broadcasting with producers and directors each wanting their content to be louder than everyone else’s, whilst not breaking the rules by going over the maximum peak level.

The Solution - Loudness To The Rescue

What we needed was a system that could measure loudness in the same way our hearing perceives loudness, provide a definite measurement for the loudness of a program and then normalise our content to a standard loudness measurement rather than normalising to peak level.

To achieve this, we needed a meter that could measure and display loudness in the same way our ears hear loudness. To achieve this, the standard loudness measurement BS1770 was developed and has become a single universal standard for measuring loudness and all delivery specs are based on this BS1770 standard.

Some governments and broadcasters across the world have chosen to address this problem with legislation. In the USA, the law is called the CALM Act, supported by the ATSC A/85 standard. France and Spain have also passed laws for the control of all their broadcast channels’ loudness, using the EBU R128 standard.

Whereas other countries like Germany, Switzerland, Austria, Norway and the UK have voluntarily implemented EBU R128 recommendations across all their TV broadcast channels. Austria has even made the bold claim that they have reduced their loudness complaints to…ZERO.

What Next?

In part 2, The Development Of One Loudness Standard, we will cover the development of one loudness standard. We explore how we arrived at a loudness measurement algorithm that works just like our ears and the various criteria we use to define and guide us when working to the new loudness delivery specifications, including K Weighting, the differences between Momentary, Short-term and Integrated loudness as well as the importance of True Peak and Loudness Range.

In Part 3, Calibrating Your Monitors, we will cover a key part of delivering loudness-compliant content - how to calibrate your monitors.  We will look at how our monitoring should be configured and provide an explanation of bass management and what your sub should be doing before moving on to a practical demonstration of how to calibrate your monitoring with a sound pressure meter.

In part 4, Creating Loudness-Compliant Mixes For Broadcast And Netflix, we will share some tips and tricks for mixing to the broadcast loudness standards for a wide variety of genres. We will include examples and demonstrations as well as explain the importance of what Mike describes as ‘loudness planning’ before ending with some specific tips and tricks for mixing short-form content like adverts, trailers and promos. 

In part 5, Preparing Content For Music Streaming Services, we will cover loudness online content and music streaming services, including the various standards for online content, loudness normalisation, album normalisation, and how to prepare music tracks for music streaming services with three free video tutorials.

In part 6, Using Loudness Meters For Music And Post Production, we will end the series by listing our selection of loudness meters in alphabetical order, and as we mentioned at the start, please note that this isn’t an exhaustive list. Where we have them, we will include tutorials and reviews of each of the meters.