Effects unit in the context of "Boss DS-1"

Distortion and overdrive are forms of audio signal processing used to alter the sound of amplified electric musical instruments, usually by increasing their gain, producing a "fuzzy", "growling", or "gritty" tone. Distortion is most commonly used with the electric guitar, but may be used with other instruments, such as electric bass, electric piano, synthesizer, and Hammond organ. Guitarists playing electric blues originally obtained an overdriven sound by turning up their vacuum tube-powered guitar amplifiers to high volumes, which caused the signal to distort. Other ways to produce distortion have been developed since the 1960s, such as distortion effect pedals. The growling tone of a distorted electric guitar is a key part of many genres, including blues and many rock music genres, notably hard rock, punk rock, hardcore punk, acid rock, grunge and heavy metal music, while the use of distorted bass has been essential in a genre of hip hop music and alternative hip hop known as "SoundCloud rap".

The effects alter the instrument sound by clipping the signal (pushing it past its maximum, which shears off the peaks and troughs of the signal waves), adding sustain and harmonic and inharmonic overtones and leading to a compressed sound that is often described as "warm" and "dirty", depending on the type and intensity of distortion used. The terms distortion and overdrive are often used interchangeably; where a distinction is made, distortion is a more extreme version of the effect than overdrive. Fuzz is a particular form of extreme distortion originally created by guitarists using faulty equipment (such as a misaligned valve (tube); see below), which has been emulated since the 1960s by a number of "fuzzbox" effects pedals.

A recording studio is a specialized facility for recording and mixing of instrumental or vocal musical performances, spoken words, and other sounds. They range in size from a small in-home project studio large enough to record a single singer-guitarist, to a large building with space for a full orchestra of 100 or more musicians. Ideally, both the recording and monitoring (listening and mixing) spaces are specially designed by an acoustician or audio engineer to achieve optimum acoustic properties (acoustic isolation or diffusion or absorption of reflected sound reverberation that could otherwise interfere with the sound heard by the listener).

Recording studios may be used to record singers, instrumental musicians (e.g., electric guitar, piano, saxophone, or ensembles such as orchestras), voice-over artists for advertisements or dialogue replacement in film, television, or animation, Foley, or to record their accompanying musical soundtracks. The typical recording studio consists of a room called the "studio" or "live room" equipped with microphones and mic stands, where instrumentalists and vocalists perform; and the "control room", where audio engineers, sometimes with record producers, as well, operate professional audio mixing consoles, effects units, or computers with specialized software suites to mix, manipulate (e.g., by adjusting the equalization and adding effects) and route the sound for analog or digital recording. The engineers and producers listen to the live music and the recorded "tracks" on high-quality monitor speakers or headphones.

An audio engineer (also known as a sound engineer or recording engineer) helps to produce a recording or a live performance, balancing and adjusting sound sources using equalization, dynamics processing and audio effects, mixing, reproduction, and reinforcement of sound. Audio engineers work on the "technical aspect of recording—the placing of microphones, pre-amp knobs, the setting of levels. The physical recording of any project is done by an engineer…"

Sound engineering is increasingly viewed as a creative profession and art form, where musical instruments and technology are used to produce sound for film, radio, television, music and video games. Audio engineers also set up, sound check, and do live sound mixing using a mixing console and a sound reinforcement system for music concerts, theatre, sports games, and corporate events.

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 disc jockey, more commonly abbreviated as DJ, is a person who plays recorded music for an audience. Types of DJs include radio DJs (who host programs on music radio stations), club DJs (who work at nightclubs or music festivals), mobile DJs (who are hired to work at public and private events such as weddings, parties, or festivals), and turntablists (who use record players, usually turntables, to manipulate sounds on phonograph records). Originally, the "disc" in "disc jockey" referred to shellac and later vinyl records, but nowadays DJ is used as an all-encompassing term to also describe persons who mix music from other recording media such as cassettes, CDs or digital audio files on a CDJ, controller, or even a laptop. DJs may adopt the title "DJ" in front of their real names, adopted pseudonyms, or stage names.

DJs commonly use audio equipment that can play at least two sources of recorded music simultaneously. This enables them to blend tracks together to create transitions between recordings and develop unique mixes of songs. This can involve aligning the beats of the music sources so their rhythms and tempos do not clash when played together and enable a smooth transition from one song to another. DJs often use specialized DJ mixers, small audio mixers with crossfader and cue functions to blend or transition from one song to another. Mixers are also used to pre-listen to sources of recorded music in headphones and adjust upcoming tracks to mix with currently playing music. DJ software can be used with a DJ controller device to mix audio files on a computer instead of a console mixer. DJs may also use a microphone to speak to the audience; effects units such as reverb to create sound effects and electronic musical instruments such as drum machines and synthesizers.

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.

U2 are an Irish rock band formed in Dublin in 1976. The group comprises Bono (lead vocals), the Edge (lead guitar, keyboards, and vocals), Adam Clayton (bass guitar), and Larry Mullen Jr. (drums and percussion). Initially rooted in post-punk, U2's musical style has evolved throughout their career, yet has maintained an anthemic quality built on Bono's expressive vocals and the Edge's chiming, effects-based guitar sounds. Bono's lyrics, often embellished with spiritual imagery, focus on personal and sociopolitical themes. Popular for their live performances, the group have staged several elaborate tours over their career.

The band was formed when the members were teenaged pupils of Mount Temple Comprehensive School and had limited musical proficiency. Within four years, they signed with Island Records and released their debut album, Boy (1980). Works such as their first UK number-one album, War (1983), and singles "Sunday Bloody Sunday" and "Pride (In the Name of Love)" helped establish U2's reputation as a politically and socially conscious group. Their fourth album, The Unforgettable Fire (1984), was their first collaboration with producers Brian Eno and Daniel Lanois, whose influence resulted in a more abstract, ambient sound for the band. By the mid-1980s, U2 had become renowned globally for their live act, highlighted by their performance at Live Aid in 1985. Their fifth album, The Joshua Tree (1987), made them international stars and was their greatest critical and commercial success. One of the world's best-selling albums with 25 million copies sold, it yielded the group's only number-one singles in the US: "With or Without You" and "I Still Haven't Found What I'm Looking For".

An electric guitar is a guitar that requires external electric sound amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar. It uses one or more pickups to convert the vibration of its strings into electrical signals, which ultimately are reproduced as sound by loudspeakers. The sound is sometimes shaped or electronically altered to achieve different timbres or tonal qualities via amplifier settings or knobs on the guitar. Often, this is done through the use of effects such as reverb, distortion and "overdrive"; the latter is considered to be a key element of electric blues guitar music and jazz, rock and heavy metal guitar playing. Designs also exist combining attributes of electric and acoustic guitars: the semi-acoustic and acoustic-electric guitars.

Invented in 1932, the electric guitar was adopted by jazz guitar players, who wanted to play single-note guitar solos in large big band ensembles. Early proponents of the electric guitar on record include Les Paul, Eddie Durham, George Barnes, Lonnie Johnson, Sister Rosetta Tharpe, T-Bone Walker, and Charlie Christian. During the 1950s and 1960s, the electric guitar became the most important instrument in popular music. It has evolved into an instrument that is capable of a multitude of sounds and styles in genres ranging from pop and rock to folk to country music, blues and jazz. It served as a major component in the development of electric blues, rock and roll, rock music, heavy metal music and many other genres of music.

Flanging /ˈflændʒɪŋ/ is an audio effect produced by mixing two identical signals together, one signal delayed by a small and (usually) gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and notches are produced in the resulting frequency spectrum, related to each other in a linear harmonic series. Varying the time delay causes these to sweep up and down the frequency spectrum. A flanger is an effects unit that creates this effect.

Part of the output signal is usually fed back to the input (a re-circulating delay line), producing a resonance effect that further enhances the intensity of the peaks and troughs. The phase of the fed-back signal is sometimes inverted, producing another variation on the flanger sound.

A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers in enclosures all controlled by a mixing console that makes live or pre-recorded sounds louder and may also distribute those sounds to a larger or more distant audience. In many situations, a sound reinforcement system is also used to enhance or alter the sound of the sources on the stage, typically by using electronic effects, such as reverb, as opposed to simply amplifying the sources unaltered.

A sound reinforcement system for a rock concert in a stadium may be very complex, including hundreds of microphones, complex live sound mixing and signal processing systems, tens of thousands of watts of amplifier power, and multiple loudspeaker arrays, all overseen by a team of audio engineers and technicians. On the other hand, a sound reinforcement system can be as simple as a small public address (PA) system, consisting of, for example, a single microphone connected to a 100-watt amplified loudspeaker for a singer-guitarist playing in a small coffeehouse. In both cases, these systems reinforce sound to make it louder or distribute it to a wider audience.

Chillwave is a music microgenre that emerged in the late 2000s. It is characterized by evoking the popular music of the late 1970s and early 1980s while engaging with notions of memory and nostalgia. Common features include a faded or dreamy retro pop sound, escapist lyrics (frequent topics include the beach or summer), psychedelic or lo-fi aesthetics, mellow vocals, slow-to-moderate tempos, effects processing (especially reverb), and vintage synthesizers.

Chillwave was one of the first music genres to develop primarily through the Internet. The term was coined in 2009 by the satirical blog Hipster Runoff to lampoon microgenres and indie acts whose sounds resembled incidental music from 1980s VHS tapes. Prior to this, the music would have been labelled as shoegaze, dream pop, ambient, or indietronica. Leading acts included Neon Indian, Washed Out, and Toro y Moi, who gained attention during 2009's "Summer of Chillwave". Washed Out's 2009 track "Feel It All Around" remains the best-known chillwave song.

Arena rock (also known as stadium rock, pomp rock or corporate rock) is a style of rock music that became mainstream in the 1970s. It typically involves radio-friendly rock music that was designed to be played for large audiences.

As hard rock and pop rock became increasingly popular, groups began creating material inherently designed for performance to crowds and major concerts. Arena rock also developed from their use of more commercially oriented sounds that were intended for radio play. The highly produced music, including both upbeat, dramatic songs and slower power ballads, features strong emphasis on melody and frequently employs anthemic choruses. Other major characteristics include prominent guitar effects and the use of keyboard instruments. Typical themes of arena rock lyrics include love, heartbreak, angst, and sentimentality.