Distortion (music) in the context of "Hardcore punk"

A definition of music endeavors to give an accurate and concise explanation of music's basic attributes or essential nature and it involves a process of defining what is meant by the term music. Many authorities have suggested definitions, but defining music turns out to be more difficult than might first be imagined, and there is ongoing debate. A number of explanations start with the notion of music as organized sound, but they also highlight that this is perhaps too broad a definition and cite examples of organized sound that are not defined as music, such as human speech and sounds found in both natural and industrial environments. The problem of defining music is further complicated by the influence of culture in music cognition.

The Concise Oxford Dictionary defines music as "the art of combining vocal or instrumental sounds (or both) to produce beauty of form, harmony, and expression of emotion". However, some music genres, such as noise music and musique concrète, challenge these ideas by using sounds not widely considered as musical, beautiful or harmonious, like randomly produced electronic distortion, feedback, static, cacophony, and sounds produced using compositional processes which utilize indeterminacy.

In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio signal representing sound or a video signal representing images, in an electronic device or communication channel.

Distortion is usually unwanted, and so engineers strive to eliminate or minimize it. In some situations, however, distortion may be desirable. For example, in noise reduction systems like the Dolby system, an audio signal is deliberately distorted in ways that emphasize aspects of the signal that are subject to electrical noise, then it is symmetrically "undistorted" after passing through a noisy communication channel, reducing the noise in the received signal. Distortion is also used as a musical effect, particularly with electric guitars.

Heavy metal (or simply metal) is a genre of rock music that developed in the late 1960s and early 1970s, largely in the United Kingdom and United States. With roots in blues rock, psychedelic rock and acid rock, heavy metal bands developed a thick, monumental sound characterized by distorted guitars, extended guitar solos, emphatic beats and loudness.

In 1968, three of the genre's most famous pioneers – British bands Led Zeppelin, Black Sabbath and Deep Purple – were founded. Though they came to attract wide audiences, they were often derided by critics. Several American bands modified heavy metal into more accessible forms during the 1970s: the raw, sleazy sound and shock rock of Alice Cooper and Kiss; the blues-rooted rock of Aerosmith; and the flashy guitar leads and party rock of Van Halen. During the mid-1970s, Judas Priest helped spur the genre's evolution by discarding much of its blues influence, while Motörhead introduced a punk rock sensibility and an increasing emphasis on speed. Beginning in the late 1970s, bands in the new wave of British heavy metal such as Iron Maiden and Saxon followed in a similar vein. By the end of the decade, heavy metal fans became known as "metalheads" or "headbangers". The lyrics of some metal genres became associated with aggression and machismo, an issue that has at times led to accusations of misogyny.

Garage rock (sometimes called garage punk or '60s punk) is a raw and energetic style of rock music that was mainly successful in the mid-1960s, most commonly in the United States and Canada, and has experienced a series of subsequent revivals. The style is characterized by basic chord structures played on electric guitars and other instruments, sometimes distorted through a fuzzbox, as well as often unsophisticated and occasionally aggressive lyrics and delivery. Its name derives from the perception that groups were often made up of young amateurs who rehearsed in the family garage, although many were professional.

In the US and Canada, surf rock—and later the Beatles and other beat groups of the British Invasion—motivated thousands of young people to form bands between 1963 and 1968. Hundreds of grass-roots acts produced regional hits, some of which gained national popularity, usually played on AM radio stations. With the advent of psychedelia, numerous garage bands incorporated exotic elements into the genre's primitive stylistic framework. After 1968, as more sophisticated forms of rock music came to dominate the marketplace, garage rock records largely disappeared from national and regional charts, and the movement faded. Other countries in the 1960s experienced similar rock movements that have sometimes been characterized as variants of garage rock.

An instrument amplifier is an electronic amplifier that converts the often barely audible or purely electronic signal of a musical instrument into a larger electronic signal to feed to a loudspeaker. An instrument amplifier is used with musical instruments such as an electric guitar, an electric bass, electric organ, electric piano, synthesizers and drum machine to convert the signal from the pickup (with guitars and other string instruments and some keyboards) or other sound source (e.g, a synthesizer's signal) into an electronic signal that has enough power, produced by a power amplifier, to drive one or more loudspeaker that can be heard by the performers and audience.

Combination (combo) amplifiers include a preamplifier, a power amplifier, tone controls, and one or more speakers in a cabinet, a housing or box usually made of wood. Instrument amplifiers for some instruments are also available without an internal speaker; these amplifiers, called heads, must plug into one or more separate speaker cabinets. Instrument amplifiers also have features that let the performer modify the signal's tone, such as changing the equalization (adjusting bass and treble tone) or adding electronic effects such as intentional distortion or overdrive, reverb or chorus effect.

Psychedelia usually refers to a style or aesthetic that is resembled in the psychedelic subculture of the 1960s and the psychedelic experience produced by certain psychoactive substances. This includes psychedelic art, psychedelic music and style of dress during that era. This was primarily generated by people who used psychedelic drugs such as LSD, mescaline (found in peyote) and psilocybin (found in magic mushrooms) and also non-users who were participants and aficionados of this subculture. Psychedelic art and music typically recreate or reflect the experience of altered consciousness. Psychedelic art uses highly distorted, surreal visuals, bright colors and full spectrums and animation (including cartoons) to evoke, convey, or enhance the psychedelic experience.

Psychedelic music uses distorted electric guitar, Indian music elements such as the sitar and tabla, electronic effects, sound effects and reverb, and elaborate studio effects, such as playing tapes backwards or panning the music from one side to another.

A guitar amplifier (or amp) is an electronic device or system that strengthens the electrical signal from a pickup on an electric guitar, bass guitar, or acoustic guitar so that it can produce sound through one or more loudspeakers, which are typically housed in a wooden cabinet. A guitar amplifier may be a standalone wood or metal cabinet that contains only the power amplifier (and preamplifier) circuits, requiring the use of a separate speaker cabinet–or it may be a combo amplifier, which contains both the amplifier and one or more speakers in a wooden cabinet. There is a wide range of sizes and power ratings for guitar amplifiers, from small, lightweight practice amplifiers with a single 6-inch speaker and a 10-watt amp to heavy combo amps with four 10-inch or four 12-inch speakers and a 100-watt amplifier, which are loud enough to use in a nightclub or bar performance.

Guitar amplifiers can also modify an instrument's tone by emphasizing or de-emphasizing certain frequencies, using equalizer controls, which function the same way as the bass and treble knobs on a home stereo, and by adding electronic effects; distortion (also called overdrive) and reverb are commonly available as built-in features. The input of modern guitar amplifiers is a 1/4" jack, which is fed a signal from an electro-magnetic pickup (from an electric guitar) or a piezoelectric pickup (usually from an acoustic guitar) using a patch cord, or a wireless transmitter. For electric guitar players, their choice of amp and the settings they use on the amplifier are a key part of their signature tone or sound. Some guitar players are longtime users of a specific amp brand or model. Guitarists may also use external effects pedals to alter the sound of their tone before the signal reaches the amplifier.