When saturating your signal, keep in mind how the harmonic formation created by the saturator will impact the tone and timbre of the signal. By knowing these different formations and how to achieve them, you can accomplish saturation that also equalizes, and even stereo expands your signal.
Saturation is typically just a combination of harmonic distortion and soft-knee compression; however, some saturation plugins have extra functionality - one, in particular, the FabFilter Saturn 2 really opens up a lot of possibilities.
One of the main ways it does this is with modulation - the main parameters you’ll use when modulating your signal with this saturator are the envelope generator and envelope follower. These can be linked with specific functions, in turn modulating the amount of distortion that occurs.
To be honest, this section is complex to the point where even after a few years of using this plugin, I’m still finding new ways that it can be utilized.
For a quick start, try one of the presets and observe how each modulation function interacts with other parameters of the saturator.
Harmonics are a somewhat simpler topic than the last one we covered - in short, we have even and odd harmonics. Even harmonics are the 2nd, 4th, 6th, and so on harmonics, as it relates to the fundamental frequency.
Odd harmonics are the odd intervals. The more you use various saturators, the more you’ll begin to memorize the harmonic formations that they create and in turn the tone.
For example, higher-order harmonics will add clarity, so if the saturator you use introduces these, you know you can use it to brighten a sound source.
Run a sine wave through a saturator and observe the harmonics if you’re curious what the saturator will create.
Following the last concept in which particular saturators can be used to accomplish specific tones, we can use saturation as a form of equalization.
Say we want our vocal to have a warmer low end - we could use an equalizer to boost this low-frequency range, or I could use a warm tube setting to create a strong second-order harmonic.
If we look at a frequency analyzer we can see that by simply enabling a saturation plugin, we, in turn, change the frequency response. Additionally, we can observe a warm tube setting and how it affects the low end.
As you can imagine, these curves will change given the various settings you use, so try to keep in mind how you can use your go-to saturator to more or less equalize your signal.
Mid-side saturation gives you the opportunity to expand or narrow your stereo image. In short, you can distort the side or mid, or a combination of the two to create a particular balance.
The more you saturate the sides the wider the image will be; the more you saturate the mids, the more centered it’ll be.
If we look at the image of 2 sine waves that have been separated into mid and side and then distorted, we can observe the effect that saturation is having on our image.
We can see how the signal expands when we distort the side over the mid and vice versa.
If we want dynamic stereo expansion, we can use some of the modulations that we discussed earlier, and link it to the drive function, in turn causing input-dependent expansion.
If you have 2 competing signals, say your kick and bass tracks, you can use specific forms of distortion to separate the 2.
Let’s say both have a fundamental at 60Hz, and you use odd harmonic distortion on the kick and even harmonic distortion on the bass.
The kick will still have its fundamental, but will also have harmonics at 180Hz, 300Hz, and maybe 420Hz.
The bass will still have its 60Hz fundamental as well, but will also have harmonics at 120Hz, 240Hz, and maybe 360Hz.
In both instances, our fundamentals are becoming easier to hear due to a psychoacoustic effect, but the harmonics of each instrument is occupying a different space in the spectrum.
Although this may be a subtle effect - when paired with some other methods, it can definitely help separate competing instruments.