The short (and maybe somewhat mysterious) answer to this question is: You should aim for -14dB Integrated LUFS and with a maximum -1dB TP (True Peak).
If you understood all that, then off you go. If not, just keep calm and carry on reading…
What is LUFS?
LUFS stands for Loudness Units relative to Full Scale - but don’t let that scare you! It is basically a measurement of volume that takes into account both human perception and the electrical intensity of an audio signal.
What we call Loudness is really how our brain perceives sound pressure. The more energy a sound has the louder it seems. The Loudness Unit (LU) is used to describe the amount of this perceived loudness.
Full Scale (FS) is the level in an audio system, or piece of audio equipment, at which the signal starts clipping or distorting. This level is marked as ‘0’, with everything below this level being measured in the negative e.g. -18dBFS, which is 18 decibels (dB) below the Full Scale point (FS).
So LUFS is simply a combination of LU and FS.
What then is Integrated LUFS?
When measuring LUFS in your DAW you might be presented with two different measurements: Short-term LUFS and Integrated LUFS. Short-term LUFS measures only a short part of the track and can be used to measure the loudness of a specific section. (How much of the track is being measured is different for different plugins.)
Integrated LUFS on the other hand continues to measure the loudness of the track for as long as the track is playing, showing you the average level of what has been played so far. You usually need to play the whole track from start to finish in order to get a measurement for the whole track.
Integrated LUFS is the measurement that streaming platforms use when they make recommendations for tracks to be submitted at a particular level. As mentioned at the start of the article, level they recommend is -14dB Integrated LUFS - which means that the average level of your track should be 14dB of Loudness below the Full Scale point.
What is TP (True Peak)?
True Peak (TP) is the maximum level that a signal reaches. So in this case, it is the loudest moment in your track. For streaming services, it is recommended to keep your track’s TP at -1dBFS, which means 1dB below the point at which your track would reach the Full Scale point and then clip or distort. Using this setting prevents any extra distortions that might occur when your track is transcoded into the streaming services system.
Furthermore, if your track’s LUFS level is louder than -14dB (so closer to 0dB), it is best to ensure that the True Peak level stays below -2dB (so more than 2dB below the point at which your track would reach the Full Scale point). The reason for this is that for louder tracks there is a greater risk of distortion during the transcoding process.