What is Audio Saturation
Audio Saturation is an internal error or let say a flaw that occurred when a magnetic tape machine to the hot level. Saturation is a type of distortion as it adds extra harmonic tones or in simple words adds the analog warmth to the original source.
In good old analog days, the mix engineers needed to push the tape beyond 0 dB to achieve soft clipping as the audio signal clips but opposite to digital clipping this type of analog clipping is somehow appealing to the people and it sounds very musical.
Why Use Audio Saturation
In digital audio workstations (DAW) that we use for creating, mixing and mustering our audio tracks, whenever the audio signal goes beyond 0dB, the DAW engine considers it as hard clipping, creates an unwanted bad type of distortion.
Most important reason to use saturation plugins when mixing inside DAW is to get that analog magical sound and bring back the life to the mixes.
Types of Audio Saturation
You will find various types of saturation plugins available on web stores, but the tape saturation and tube saturation plugins are the most popular ones.
When a signal is being sent to a tape recorder to be recorded, now the plastic film that you know to be the tape has a surface which is made of iron oxide powder to record a signal onto the tape the recording head of the recorder magnetizes each of the iron oxide particles on the tape by varying amounts over time this becomes a linear representation of the original alternating current this is where saturation comes in a tape recorder. See Understanding Tape Saturation free tutorial for more details.
The tube saturation gives the certain type of analog warmth to the audio signal. Vacuum tubes are used in popular hardware units and their software VST emulations to create color into the incoming audio signal. To be able to work successfully of the tube saturation you need minimum three elements, cathode, anode and the control grid. See Understanding The Tube Saturation a free tutorial for more details.
Other saturation plugin types like tube or valve based saturation, transistor-based saturation, etc are also available, these various types of saturation plugins have various usage and create different types of analog character to the audio.