Understanding the ITU 1770 Loudness Standard
If you are passionate about audio and work to create audio content, you must have heard of ITU 1770, or you may already know it very well. This standard is an important parameter of product quality and consistency, so it is important to fully understand it.
What is ITU 1770? It is a parameter developed by the International Telecommunication Union, which defines an accurate method for measuring and standardizing the volume of various audio materials. In other words, it gives us a solid basis for balancing volume levels across platforms and devices, from radio and TV to broadcasting and gaming.
In this post, we’ll look at this standard to learn how it’s used in the industry and how you can use it in your sound design projects, and the first thing to understand here is the concept of “loudness”. Talking about “length” in meters is a precise and well-defined physical term, but when talking about “loudness” things are much more complicated. Loudness refers to how we, as humans, perceive sound level and is a variable that is not limited to physics but involves aspects of perception that vary from person to person. Thus any loudness measurement attempts to use reasonable and practical criteria, usually based on statistical studies of how large groups of people hear and evaluate sound levels.
Over time, several proposals have emerged to define loudness measurement procedures. The classical VU meter is a basic experiment that has been used for many years, but today we have much more ambitious and useful international standards, such as EBU R 128, which is based on ITU-R BS.1770. There are other similar standards such as ATSC A/85, OP-59, ARIB TR-B32, AGCOM 219/09/CSP, and ASWG-R001 that are used in different industries or specific regions of the world.
EBU R-128 was established as a uniform volume standard to avoid sudden changes in sound level between different audio content. EBU R-128, developed by the European Broadcasting Union, is considered one of the most comprehensive and influenced by the original version of BS.1770. These standards define common measures of loudness, dynamic range, and maximum level to ensure comfortable coexistence between different types of content. Although originally used for television and radio, they have expanded to other areas and are also used by online platforms such as iTunes or Apple Music. Before these rules came into effect, there were no clear standards and many artists were looking for a strong sound through overly compressed mixing and mastering. At this time there are still very high-quality records that make suggestions to keep more vibrancy in the music. For example, it is recommended to aim for -14 dBFS for low dynamic styles and -20 dBFS for more “natural” styles such as classical or jazz.
Before the introduction of standards such as EBU R-128, there was no clear, universal standard for the volume of audio content. As a result, much music is now mixed and mastered with heavy compression that destroys the initial dynamics. Records can still be found with an average level of -6dBFS, leaving little room for peaks compared to the average. To address this, volume targets such as -14 dBFS for low dynamic music and -20 dBFS for more “natural” styles such as classical or jazz are suggested. The EBU R-128 standard defines loudness metrics such as instantaneous, short-term, and integrated loudness, as well as loudness range (LRA) and peak measures. These standards and metrics help maintain dynamic operation and set the benchmark for audio content production.
The ITU 1770 standard, which specifically uses the EBU R-128 standard, is widely used in the audio industry to ensure quality and consistency in audio production. It is used in television, radio, music, online video platforms, and other fields. Radio and television stations use these standards to ensure consistent sound levels and avoid sudden changes in volume; that is why online music and video platforms such as YouTube or Spotify, in addition to those already mentioned, are also implementing these standards to ensure a uniform listening experience for users.
OK, how to use ITU 1770 to your advantage?
To implement it in your sound design projects, first of all, use a compatible volume meter, meet your set volume target, avoid overcompression, test and adjust it on all devices and keep up with the latest standards. To achieve a balanced mix, accurate editing, and a high-quality listening experience you must consider the dynamics of the music, have accurate editing, use effects creatively, monitor and control the mix on different playback systems, and, of course: consider volume and balance. Sound quality and the listening experience are fundamental, and implementing the right standards, such as ITU 1770, is, therefore, a useful tool to achieve these goals.
If you want to learn about this and other topics on sound design, mixing, and audio editing, don’t miss our content; and, if you need professional advice for your audiovisual projects, please contact us: at Enhanced Media Sound Studio, we will be happy to take your works to the next level of quality.
