I imagine you’ve heard a million times that analog sounds warm and organic compared to digital. But why is that? Part of the magic is how the physical components saturate the sound in a way that we would describe as musical, generating new, upper harmonics from an audio signal. Generating a similar sound scenario in the digital realm is as easy as adding a saturation plugin. EQ plugins are also tools which boost frequencies in order to enhance a digital signal – but why are people increasingly turning to saturation plugins over EQs to enhance their mixes and how does a producer utilise this audio phenomenon in replacement of EQ in the best possible way? This is the question we aim to answer in this article, and at the same time, we want to give you five ways to utilise saturation where it can be better used over EQ.
Saturation is the natural phenomenon that occurs in the analog world when an input signal comes in really hot and pushes the analog hardware to the limits of its design. The equipment cannot deliver any more voltage even if you increase the gain, becoming over-saturated (hence the name, saturation). The best example of saturation would be how you could hear a sound getting crunchier as you increase the drive knob on the first tube amps. This knob was initially designed only as a volume control. Later, driving an amp too hard would be used as a creative effect called overdrive. What is really happening inside the circuitry is that the output signal is said to be clipping, because it cannot cross a certain voltage ceiling. This results in a rounded waveform around the maximum and/or minimum values. In the frequency domain, it creates some new harmonics whose frequencies are related to the spectrum of the input signal as well as a boosted signal. We call this alteration harmonic distortion, which is a similar process used also by bass enhancement.
In terms of code, saturation is quite a simple effect to implement. The most basic kind of saturation can be obtained just by clipping the amplitude of the signal to 1. In the digital world, signals are usually constrained between minus 1 and 1. Those numbers represent the maximum amplitude of the signal that will later be converted to the min and max voltages of your hardware. This kind of clipping, usually called hard clipping, will generally sound harsh and digital, just as the clipping that occurs in your DAW when your master bus is crossing those thresholds. To obtain a more subtle and musical effect, we will generally apply a knee to have a gradual effect, reducing the amplitude as it is going higher. This type of effect is usually called wave shaping.
Those two types of saturation, generic hard and soft clipping, can be found in a lot of saturation plugins and can do the job in a variety of situations. However, if we want to mimic a particular type of saturation, we often need to model the electronic components, such as diodes, tubes and transistors, but also the physical behaviour of the whole schematics. One goal can then be to find the characteristic curve that we will use for the wave shaping.
Unfortunately, sometimes we need to go deeper to properly model a circuit, as we cannot treat such complex schematics as memory-less systems. In particular, hysteresis is a phenomenon that has a very characteristic sound. It occurs in magnetic devices and such (transformers or tapes for example) and is caused by their fast and alternating magnetization and demagnetization. Also, part of the sound of legendary saturation units is due to processing happening around the saturation itself. Tone stacks especially have been known to matter a great deal in the popularity of guitar pedals, such as the typical mid scoop of Marshall distortion or the high shelf of a Klon Centaur.
Using saturation in the place of an EQ is becoming an increasingly more utilised way of boosting and enhancing frequency content, with some engineers like “Alex Meyerson” saying that they’re rarely using any EQ in their mixes at all. The advantage of using a saturation over EQ in some situations is clear: because a saturator essentially clips a signal to boost harmonic content, you create a boost at targeted, harmonic frequencies above the signal’s fundamental frequency, enhancing the frequency content in a similar way an EQ does. The big advantage here is that you create a boost in frequency content as you clip the signal, so you achieve the outcome of boosting a desired frequency range without boosting the signal and overall level of your mix. Another advantage is that you don’t boost unwanted, muddy frequencies, which can be easily done with an EQ plugin when not used correctly. There are of course downsides to this, as some saturators don’t allow you to target frequencies unlike with an EQ, but some do, including the denise audio God Mode plugin and the Soundtoys Decapitator using the tone dial.
Saturation on the master channel is a trick nowadays, but it was literally the standard of music production. Tape would be the recording medium par excellence and its specific harmonic distortion is responsible for the mojo that we hear on all the classics. Its soft clipping generates odd harmonics, responsible for the punchy sound when driven hard, so we get extra loudness and bite. We can use the push pull graph of god mode to tilt the frequency response to drive the hi-s faster and get extra tape warmth. Bonus: Use God Mode on every track to emulate an analog tape mixing session before hitting the master bus if you want to go for a heftier vintage sound! You can use different tilt curves to enunciate the various groups of instruments and make them glue together. Let denise audio’s nrec show you how to do that, as well as two other tricks, below.
If there is one instrument that screams “SATURATE ME” more than anything, it’s drums. You can really exaggerate the parallel distortion on every single mic track and get a stark and bold sound without ruining the phase coherence. If you’re making DNB or Blues, or Jazz even, you can use saturation to darken the cymbals, or to give bite to the kick, make the toms pop out of speakers. Alternatively, you can put in on the whole bus, as described by Venus Theory, below.
Vocal saturation is another classic. From Aretha Franklin up to contemporary electronic production, some nice and crunchy distortion is a great way to get your vocals upfront, and to enhance clarity and brightness without creating phase artifacts typical of EQ boosts that can quickly make a vocal track sound unnatural and harsh. Let Czar explain how he does it on vocal tracks.
A great way to give consistency to a bassline is saturation for sure – it makes it pop even on small speakers without using EQ, which results in easier gain staging and stabilizing the dynamics as a bonus. Depending on the colour of the distortion device in use, you can give a bassline more growl or more grit, which will help the bass stand out in specific areas of the spectrum where there is more room for it. This technique instantly gives more presence to the sub, as explained by Fabio from Noise London, below.
An old trick is saturating the fx returns. It helps the reverbs glue better with the rest of the music by making them thick and dark, getting rid of the digital harshness/graininess, which has the reputation of being the most responsible of sterile digital in-the-box mixes. Let Marlon from White Noise Studio explain how he uses saturation on a reverb send, below.
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