Once upon a time there was an analog recording
Until at least the early 1980s, most recordings were made with analog material, and more specifically with magnetic tapes.
With these bands, it was necessary to maximize the signal / noise ratio. For this, recordings were often made as high as possible, close to “the red zone”.
This limit, specifically, corresponds to the 0 VU measurement that can be read on analog level meters.
If the signal exceeded this value and entered the red zone, a fairly hot saturation appeared and, in any case, progressive intensity. Undoubtedly, this contributed to giving the side that today we describe as “vintage” to the recordings of the time.
Cutout
Today, the situation is no longer the same because the operation of digital recording is quite different.
First, the digital signal is measured in dBFS, a unit that actually corresponds to the difference between the signal level and the highest signal that can exist. It has nothing to do with the 0 VU measurements we discussed earlier.
In other words :
As long as your signal remains below 0 dBFS, there will be no problem or coloration except for that of your preamp / processing chain
If the signal exceeds 0 dBFS, it cannot be played when listening (for example, with headphones or speakers, after digital> analog conversion has been performed).
Specifically, what will happen?
Well the sound will be trimmed.
The clipping phenomenon
That is, any signal that exceeds the 0 dBFS threshold will be truncated purely and simply. The consequence is a strong distortion devoid of any musicality, unlike the distortion that would be found in analog material.
Suddenly, if you record a sound whose signal exceeds this limit, it will be distorted by distortion and generally unusable.
An example will be clearer: an acoustic guitar recorded too loudly.
It sounds distorted and cropped. It’s horrible, isn’t it? 🙁
Furthermore, we can see that the shape of the signal is truncated at the peaks due to the phenomenon of What level to record then?
Perhaps while thinking about imitating analog recording, many people record their voice or guitar aiming at a level of 0 dBFS.
The problem is that doing this makes it very difficult to make sure that the signal is not clipped.
In fact, even if you don’t hear it during follow-up, it is highly likely that a peak or two will exceed the fatal threshold of 0 dBFS. And when you notice it during mixing, it will be too late …
Also, by trying to reach this level, you can overload your preamps a bit. If you are using entry-level or mid-range equipment, it will probably affect the sound quality.
In fact, if you record in 24-bit (which you should), the available dynamic range is wide. Therefore, it is not necessary to take sound at high volume.
Rather, it is much better practice than aligning yourself with an average RMS level between -15 and -22 dBFS.
When it comes to peaks, it is okay if some peaks drop to -12 or -10 dBFS. The main objective is to keep enough space to apply its effects during mixing.
On the other hand, once the mix is finished, it is during mastering that it will raise the general level of your mix to reach, at will, the volume that can be found on commercial CDs. And it is only then that the maximum level will be close to 0 dBFS.
