Non-linear

Overview

The term "non-linear" is used to describe a process where the output is not directly proportional to the input. Clipping is an example of a non-linear process.

Basics

A non-linear process in audio is usually characterized as a form of “distortion.” Some examples are clipping, analog tape saturation, "hard limiting" with very fast attack and release times, or distortion caused by transformers or tubes. Another example is a bad galvanic connection (between metal contacts), which can sometimes act in a manner similar to a diode and only allow signals above a certain level to "pass" normally.

Non-linear processes can also take the form of digital emulation of analog circuitry such as emulation of tubes, transformers, or analog tape.