What the heck is dBFS, true peak, RMS, integrated loudness and LUFS? Why do I need to know these strange appellations? Well, the studio is closed due to Covid-19 and we figured we would try and tell you a bit about what we strive towards with Audio Levels.
As a professional Mastering Engineer I thought I would share insights in to technical terms referring to audio levels and loudness. A customer might tell me: “we need a track with an integrated loudness of -23 LUFS, a dynamic range of ≤15 LU and a true peak of max -1 dBTP”. Even if you’ve been mastering audio for a few years you might be thinking: “huuuuuh…?”
By now you’ve probably heard about the loudness war, and we all know what it sounds like when audio “peaks”, “clips” or hits the “red zone”. So far so good. But in order to make your audio sound pleasant and meet industry requirements, you need to know a thing or two about setting your audio levels right, and how to approach loudness when creating audio. Here’s a fun video explaining what the loudness war does to audio in practice
All you need is LUFS?
Audio produced for a specific medium should always sound pleasant, dynamic and more or less “equal” in terms of perceived loudness. Unfortunately your basic DAW meters aren’t giving you the whole truth about your audio. These meters display audio in dBFS (decibels relative to full scale) and only tell you whether your audio signal is clipping or not. To judge actual loudness, our ears respond to average levels, not peak levels.
The new standard for measuring audio loudness is LUFS (loudness units relative to full scale). It was developed to enable normalisation of audio levels, and matches how our ears actually perceive sound. LUFS meters will also tell you the integrated loudness of your audio, which is similar to RMS (root mean square) but more truthful in terms of our hearing. RMS tells you the the average power of the signal, but LUFS integrated loudness is more accurate in terms of our perception of loudness.
The integrated loudness can be understood as the “overall” level of your audio. It’s also good to keep in mind that different meters serve different purposes. You will still need to use your dBFS meters to make sure your signals aren’t clipping.
How loud is loud enough when it comes to Mastering?
Your audio should always be loud enough. What this means varies depending on how noisy the environment is (imagine in-flight entertainment), what device you are using (e.g. an iPad with headphones on the bus), and what the intended end medium is (e.g. your home TV set or a movie theatre). Especially in broadcast media (TV, radio, etc.) there are standards that require the audio to have a strictly defined integrated loudness level, most commonly -23 LUFS. This is to ensure healthy sounding audio and to avoid those annoying dynamic bumps between commercials and programme audio.
Summing it up
When mixing to LUFS values, your mixes will sound more consistent. The dBFS scale only measures the electrical level of the sound. If you try mixing to a level of e.g. -15dBFS, your results will likely hit different LUFS levels every time and might end up sounding different.
If you don’t yet own a LUFS meter, remember to pay attention to your RMS readings. If your dBFS peak levels go higher than -3dB, you might be in trouble. As a rule of thumb when sending your music to us – when we open again – aim for RMS readings around -18dBFS and -14dBFS. You should be OK then.