The prevailing wisdom of “mix with your ears” is that way for a reason. Music production and Mixing is not about what the song looks like, after all.
Still, there is a benefit to using visual examples as a metaphor when we speak about audio. So using this perspective, let’s take a brief look today at what Saturation is and why we would want it in our music.
This is a picture of a Neve 5088 console with no saturation applied to the picture.
Here is the same picture, but with only a bit of saturation. Notice how the colors seem more vivid?
This is a picture with too much saturation applied.
Notice how the colors are overblown and look cartoony? Audio signals, when overblown like this, have added harmonic distortion and reduced dynamics. Although saturation in color does not directly trade for saturation in audio, the general principle applies. We are, after all, dealing with waves propagating through an air medium.
This visual metaphor is the essence of what saturation does to an audio signal. While the result can feel a bit like compression, and indeed there is always a bit of compression involved in saturation, it is distinctive and different. Also, though distortion is one of the most perceived artifacts of saturation, it is not strictly a “distortion” effect. So what exactly is Saturation?
What is Saturation?
In any studio, before the advent of digital “in the box” mixing, engineers would record on two-inch multichannel tape machines, or at the very least they would mix down to half inch reels. Tape is based on magnetism and can only hold so much of the audio signal before becoming saturated.
Like supersaturated salt, there is just nowhere for the leftover signal to go.
The end result is that the tap machine and tape would begin to respond in non-linear ways to the signal being fed to it. This results in complex even and odd order harmonics becoming more resonant and hence more emphasized. As the tape head would soft clip, the total harmonic distortion would increase. Additionally, a natural compression happens as the signal fills out the space left to it as it becomes too saturated. There are a variety of factors that lead to different subtle results with saturation. The number of saturation plugins should indicate how many flavors of saturation there are. As with all things audio, practice with your ears to learn more about the effects of saturation on your music. Also, remember that if you arbitrarily add saturation to everything your tracks will get spongy. They will lose definition as the distortion and resonant frequencies gain dominance. If used correctly, and always to address a need in the music, you can use saturation to provide more life to the over-precise and sometimes sterile music that comes from the digital domain. Saturation represents the errors inherent in early audio technology. We raced away from this as digital took hold, only to realize we had lost some vital mojo from those early errors in signal transfer. It turns out that it is as true here in the audio world as it is in life.
It is our Errors, not our Perfection, that gives us character and defines us.
-NiX – Trackhammer Studios