Saturation vs Distortion
Both are nonlinear, yet saturation keeps the shape of a transient while distortion rewrites it.
Related
Drive a saturator to where a distortion pedal lives and a vocal does not get thicker; it hardens sooner. Both are nonlinear. The difference is how abruptly the curve bends and how hard the input is pushed.
The curve sets the tone
Saturation uses a soft knee: past a point, gain falls gradually, peaks round off, and low-order harmonics appear first. Distortion approaches a hard knee, flattening everything above the threshold so square edges add many high harmonics. Push one plugin harder and saturation becomes distortion. The border is a working point, not a label. A stage that stays clean in soft playing and hardens under a heavy attack is already close to a hard knee.
A side-by-side view
| Dimension | Saturation | Distortion |
|---|---|---|
| Transfer curve | Soft knee, gradual | Hard knee, abrupt |
| Drive | Little; peaks round | Much; waveform squares |
| Dynamics | Attack survives | Attack flattened |
| Harmonics | Mostly low order, level-dependent | Many high orders, fixed tone |
| Usual place | Bus, vocal, bass | Guitar, synth, sound design |
Level comes before the knob
A nonlinear stage sees input level. If the EQ before it adds 3 dB, the amount of saturation changes with it. Match input loudness before comparing two kinds of drive, or you only hear which one is louder. A 2 dB difference at the input moves the harmonic balance to another step; comparing two plugins at fixed settings then measures level, not character. Blend a little dry signal to keep the attack, starting around ten percent mix.
Where it goes wrong
A distortion stage without oversampling folds high frequencies, and cymbals and sibilance turn gritty first. Bass that loses its pitch outline usually has too many low harmonics packed together. Stack several gentle stages and the result is compression, not weight. On material that is already dense, more saturation only costs separation.
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Along the same line
Sources
- Zölzer, DAFX.
- FabFilter, Saturn 2 user manual, drive, mix and oversampling controls.
- Sound On Sound, saturation and harmonic distortion explained.