Loudness standards define how to measure audio levels in a way more similar to how our ear works. Among other things, the Loudness considers an extended period of the material in order to calculate an average level.
Oliver Baumann*
Although most Latin American countries have not implemented laws that define volume levels or "Loudness", it is an issue that begins to have increasing importance. Especially if you produce content for streaming, whether over the air, cable or streaming, it's time to familiarize yourself with the subject.
Loudness standards attempt to equalize sound levels from different sources. For example, in a radio station that plays music from different styles and eras. Typically older recordings have a lower volume. Another example would be a TV channel in which you feel a difference in volume between movie and batch of commercials. Due to recurring complaints from the public, it was decided to match the levels and create the Loudness standards.
Loudness vs. Volume
"Volume" is a colloquial way of talking about how loud a sound is heard. More technical would be to use the term "sound pressure level" or SPL. The problem is that SPL only considers an instantaneous measurement and does not take into account how we hear sound.
Two main phenomena make SPL not ideal for representing our acoustic perception:
- The human ear attenuates sound impulses of very short duration. (e.g. the beating of a drum)
- our auditory system is more sensitive in the middle frequencies (3 to 4kHz, where the voice is located) and less sensitive in high and low frequencies.
Loudness standards define how to measure audio levels in a way more similar to how our ear works. Among other things, the Loudness considers an extended period of the material in order to calculate an average level.
LUFS and LKFS
The Loudness scale does not use dB as we know in many teams, but speaks of "Loudness Unit - LU). LUFS and LKFS are synonymous and represent identical values. One Loudness Unit or LU equals one dB.
Why is it important?
Even if the legislation in your country has not defined which standard is to be adopted, there are different reasons to monitor the levels of Loudness in your company:
- a consistent level of Loudness offers a more pleasant experience to your audience, without the hassle of volume jumps between varied content.
- Different work areas such as production, post-production, etc. adhere to a standard and will be able to work with the material without degradation of sound quality
- if the material produced is transmitted by any streaming platform (Netflix, Spotify, YouTube, podcast, etc.) these companies require a certain level of Loudness.
- if the production is to be sold abroad, it will be necessary to observe the Loudness rules in force in the country of destination.
How to monitor the level of Loudness?
There are a number of software and plugins that display Loudness bars in graphical form on a computer screen. The disadvantage is that they require processing from the same PC that is processing the audio and also occupy an area on the screen (possibly in competition with editing software).
A more professional solution is an external meter such as the TM3 from the German brand RTW. Such a solution can be placed on the artboard and allows various audio parameters to be displayed at any time, including Loudness, phase, frequency response and more.
*Oliver Baumann is the president of Clear Cut, Inc.
