What is saturation? Saturation is an audio effect fusing soft-knee/program-dependent compression with harmonic generation/distortion. With so many saturation plugins on the market, 11 stand out as being top performers. Saturation is an essential tool in the audio engineer’s toolbox when dealing with digital audio, which is sterile and clean relative to analog. Plugins are, therefore, invaluable assets for the modern audio engineer. We’re currently living in the age of digital audio, and in-the-box mixing within a digital audio workstation is commonplace.