What is Saturation?
Saturation is a mild, musical form of distortion that adds harmonics to a sound by gently overdriving it — emulating analogue tape, tubes or transistors — making elements sound warmer, denser and more audible on small speakers.
In techno production, saturation is everywhere: on kicks to add mid-range presence, on rumble buses to glue reverb into a bassline, on percussion for grit, and on the master bus for density. The added harmonics let low-frequency content be perceived on speakers that can't reproduce the fundamental. The practical rule: saturate in stages with small amounts at several points in the chain, rather than one heavy dose — and always A/B at matched volume, because saturation makes things louder, and louder always sounds better at first.