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DSP Audio Effects: Distortion & Saturation

This library guide offers a comprehensive introduction to audio effects (FX) processing—also known as audio signal processing—which can occur in either analog or digital form. Given the widespread use and affordability of digital technologies, the focus h

Definition

Harmonic distortion in audio production refers to the alteration of an audio signal that adds additional harmonics, enriching the sound and creating a fuller, warmer audio experience. While it can enhance certain elements like vocals and instruments, excessive distortion may lead to a loss of clarity and detail in the mix. The terms distortion, harmonic distortion, and saturation are often used interchangeably, though their meanings can vary depending on context and perspective.

Distortion & Saturation (Audio University)

Harmonic Distortion Explanations

Harmonic Distortion (Wikipedia)
Harmonic distortion adds overtones that are whole number multiples of a sound wave's frequencies. Nonlinearities that give rise to amplitude distortion in audio systems are most often measured in terms of the harmonics (overtones) added to a pure sinewave fed to the system. Harmonic distortion may be expressed in terms of the relative strength of individual components, in decibels, or the root mean square of all harmonic components: Total harmonic distortion (THD), as a percentage. The level at which harmonic distortion becomes audible depends on the exact nature of the distortion. Different types of distortion (like crossover distortion) are more audible than others (like soft clipping) even if the THD measurements are identical. Harmonic distortion in radio frequency applications is rarely expressed as THD.
Total harmonic distortion (Wikipedia)
The total harmonic distortion (THD or THDi) is a measurement of the harmonic distortion present in a signal and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency. Distortion factor, a closely related term, is sometimes used as a synonym.

Distortion & Saturation Plugins (Free & Paid)