Historically, with analogue recording, it was often necessary to set input levels as high as possible to the point that the signal is just below (or sometimes exceeding, for effect) the maximum level that the recording medium (e.g. tape) can handle. This is done to try to offset the fact that tape has a fairly low signal to noise ratio, so quiet recordings can lose some detail as it gets buried in ‘tape hiss’.
For example, good quality tape machines tend to have a signal to noise ratio of somewhere between 60-70dB. In contrast, a Scarlett 2i2 2nd Generation interface has a dynamic range of 106dB (A-weighted), with an Equivalent Input Noise measurement of -128dB (A-weighted).
In practice, with digital recording (particularly at 24-bit) trying to record as ‘hot’ as possible is not particularly necessary and it can make things more difficult to balance later on. Digital clipping is almost always undesirable and if multiple tracks are recorded very loud close to the maximum digital level (0dBFS) then the sum of these tracks will likely exceed this, causing unwanted distortion.
What is gain staging?
The common misconception is that we should record all tracks as loud as possible and, when mixing, try to get the peak level on our master buss as close to 0dBFS (without actually hitting that point) as we can to end up with a ‘loud’ mix.
This tends to make mixing quite tedious – if the mix is pushing 0dBFS already and you decide you’d like to raise the volume of one track slightly, this single mix move can send your master into the red and, instead, you would need to lower the volume of all other tracks to compensate for this.
Gain staging is the act of ensuring 'healthy' levels throughout each stage of the recording and mixing process - too low and you're not utilising the full resolution of the recording medium and you might run into noise issues, too high and you run the risk of causing overloads.
Providing each track is recorded well, with a sensible microphone for the application running through a good quality microphone preamp, there is no reason to try to push 0dFBS at the recording or mixing stages. Instead, when recording, aiming for a more conservative level (e.g. peaking around -10dBFS) means that there is some headroom still available should the musician play a really loud note.
When mixing, aiming for a similar peak level at your master buss makes it far easier should you decide later on that something needs to be turned up since you’ve left headroom available to do that.
How do commercially produced mixes sound louder than mine?
The step that tends to add the greatest increase in ‘loudness’ comes after the final mixdown, during the mastering stage. Typically this is achieved by the use of compressors/limiters to reduce the dynamic range of the track, meaning that the difference between the peak level and the lowest level is decreased, resulting in a higher ‘average’ volume.