Sound Distortion

Distortion in the context of music is a word that is often tossed around by people who do not have a sufficiently clear or deep understanding of what it actually is. Fundamentally, distortion describes a change in a sound's waveform that occurs as the sound is being transmitted electronically or digitally. Viewing a wave form digitally can illustrate distortion quite well. The following image shows an audio signal and then the same signal after being distorted:

(Source)

Given the focus on sound, we also want to be able to hear and recognize distortion. The guitar in the following video presents a clearly audible difference between a more pure sound and a distorted sound:

An interesting takeaway from this video is that distortion is not something that is intrinsically bad; many guitar and bass amps have a distortion knob as a feature. Moderate and proper usage of distortion can often be used to enhance the sound of an instrument in the right musical context, but what causes this change in a sound's waveform?

There are two main categories of distortion: linear and nonlinear (commonly harmonic distortion). In linear distortion, the amplitude of different parts of the sound wave are changed, and in nonlinear distortion, different frequencies or harmonics are added to the sound. This explains why distortion can be utilized in a beneficial way - adding appropriate harmonics can add complexity to a sound while adding clashing harmonics can make something sound inharmonious. To add a bit of information about how electronics pertain to distortion, "Harmonic distortion in amplifiers is usually caused by the amplifier needing more voltage than its power supply can provide. It can also be caused by some part of the internal circuit (usually the output transistors) exceeding its output capacity"(Source).

The two main branches of distortion, linear and nonlinear, can be broken down into many different types of distortion. Harmonic distortion is often the type of distortion that people refer to when speaking about distortion, and I have addressed it already, but other types include bandwidth distortion, intermodulation distortion, dynamic distortion, temporal distortion, noise distortion, and acoustic distortion. If you are interested in more information about these specifics types of distortion, this source provides descriptions with good depth about all of them.

Works Cited:

 Butterworth, Brent. "What Is Distortion?" Gizmodo. 01 Aug. 11. Web. 22 Jan. 2016.

"Types of Audio Distortion." Parallel Audio. Web. 22 Jan. 2016.