Distortion and Overdrive

How three degrees of clipping rewrite harmonics and dynamics rather than merely adding dirt.

Related

HarmonicsClippingElectric guitar

The question

Distortion, overdrive and fuzz are three degrees of the same nonlinear family. They change harmonic structure, dynamics and frequency response, not just how dirty the sound seems.

How it works

Once a signal exceeds the linear range, it is clipped, and clipping creates new harmonics. Symmetrical clipping favours odd harmonics and sounds hard; asymmetrical clipping adds even harmonics and sounds warmer. Overdrive has a softer knee, distortion is harder, and fuzz pushes gain toward a square wave. Input level sets the amount of clipping, so pre-gain matters more than the drive control alone. Clipping also compresses dynamics, and low-frequency intermodulation turns chords muddy.

Settings and what you hear

Start with about 3 dB of drive, use tone to shape the clipped high end, and keep mix at 30 to 50 percent to retain the original transient. Before distorting a bass, high-pass it below 100 Hz to avoid low intermodulation. A little distortion on a voice adds presence; too much grabs the sibilants.

What to listen for

On a sustained organ chord, hear how clipping flattens the attack. On a distorted guitar, listen for a new hum under fifth chords. Pull mix from 100 to 40 percent and the grain of the original pick returns.

Common misconceptions

That distortion only makes a sound dirty; that digital distortion must sound worse than analog; that more drive is always better.

Sources

• Udo Zölzer, DAFX — Digital Audio Effects, nonlinear processing chapter — background checked, not quoted
• Julius O. Smith, Physical Audio Signal Processing, nonlinear distortion sections — background checked, not quoted

Used for fact-checking only; all prose is original.