Saturation

Saturation in mixing and mastering refers to a type of distortion that adds harmonics to an audio signal. It can be used to enhance the warmth, character, and perceived loudness of a track. This article is about to explain the guts of saturation in answering 5 questions.

  • What is Saturation?
  • Why do we use Saturation in mix and mastering?
  • How does Cassiopeia create Saturation?
  • Why is Cassiopeia so transparent sounding?
  • How can I use Saturation in my mix?

What is Saturation?

Analog equipment such as tape machines and tube amplifiers naturally introduce harmonic distortion when processing audio signals, which can add a pleasant warmth and richness to the sound. Saturation plugins or hardware processors attempt to emulate this effect by adding controlled amounts of harmonic distortion to the audio signal.

In other words the fact that analog audio equipment is mostly non linear crates distortion by any means. So saturation is nothing else then distortion but in a more gentle/subtle way. During the last years more and more producers/mix engineers tried to get back to a more characterful and dense mixes while introducing/allowing saturation in their mixes since digital audio processing is by default pure linear.

Why do we use Saturation in mix and mastering?

Saturation is used in mixing and mastering to add warmth, richness, and character to audio recordings. Saturation is a type of distortion that adds harmonic content to a signal, giving it a fuller and more lively sound.

It can be used to emulate the sound of vintage analog equipment or to add grit and texture to a digital recording. Saturation can also be used to control dynamic range and prevent digital clipping. When a signal is saturated, the peaks are compressed, which can help to prevent clipping and allow for a higher overall level without distortion.In mastering, saturation can be used to glue together multiple tracks and create a cohesive sound. It can also be used to add a sense of depth and dimension to a mix. Overall, saturation is a powerful tool that can be used to enhance the sound of audio recordings and bring out their full potential.

How does Cassiopeia and Lyra create Saturation?

The answer might be quite simple but its implementation might be different. First of all cassiopeia uses vacuum tubes. To be more specific triodes. Vacuum tubes tend to gently fade into saturation way before they really clip. Better said compared to transistor or digital clipping a tube does a soft – clipping.

The graphic below shows that the black line clips right when the ceiling is reached. Compared to the purple line we can see that the clipping is introduced “earlier” so the harsh edge limited and formed as a much smoother/softer curve.

 

 

hard vs. soft clipping

The graphic below shows different levels of clipping. And this is actually how cassiopeia and lyra work. The ceiling (maximum headroom) is lowered when the saturation knob is turned counter clock wise. This is quite similar to a limiter. The resulting effect is a transformed waveform from a sine wave towards a more rectangle shaped waveform with smooth edges.

 

The result of bending the wave form is a harmonics frequency spectrum which is qualitative illustrated below according to the wave forms.

Why does Cassiopeia and Lyra sound so transparent?

To answer this question we first need to take a look at the block diagram of cassiopeia & lyra.

The saturation is not performed on the entire freq. spectrum as shown in the signal flow. Before the Saturation (Tube) there is a Tilt Filter with a center freq. of 500 Hz. This filter is lowering the low mids about – 6 dB and lifting mids and highs + 6dB. After the saturation there is another tilt filter in reverse. Which makes the response nearly flat.


block diagram cassiopeia/lyra

This has mainly two reasons:

1. The Bass freq. are not touched/destroyed/mudded to much by the Saturation but higher freq. are more enhanced and make the tube react more on them.
2. The Saturation is taking more care of the transient to “fatten” these while leaving low freq. intact.


original vs. saturated signal

The overall result is that cassiopeia & lyra sound quite transparent unless you are not going to intense with the saturation and intensity (dry/wet). In the plugin (color knob) the center freq is adjustable/sweep-able and it was initially created to find the sweet spot for the hardware of 500 Hz which works in most scenarios very well and is fixed in the HW. We did not wanted to build a stomp box rather more a subtle saturator which keeps the quality of the incoming signal intact. – So you just hear it when you turn it off.

 

how can I use saturation in my mix?

There are several ways to use saturation in your mixes. Here are some common techniques:

  • Saturation on individual tracks: You can use saturation plugins on individual tracks, such as drums, vocals, or guitars, to add warmth and character. Try experimenting with different saturation settings and levels to find the right balance.
  • Saturation on buses: You can also apply saturation to buses, such as a drum bus or a vocal bus, to glue together the elements and create a more cohesive sound. This can also help to control dynamic range and prevent clipping.
  • Saturation on the master bus: You can use saturation plugins on the master bus to add a sense of warmth and richness to the entire mix. However, be careful not to overdo it, as this can result in a muddy or distorted sound.
  • Parallel saturation: You can use parallel processing to add saturation to a mix without affecting the original signal. Simply duplicate the track or bus, apply saturation to the duplicate, and blend it with the original using a send or mix knob.

When using saturation, it’s important to use your ears and listen critically to the results. Don’t be afraid to experiment and try different settings to find what works best for your mix.