Overdrive (music)
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Distortion and overdrive are forms of
audio signal processing Audio signal processing is a subfield of signal processing that is concerned with the electronic manipulation of audio signals. Audio signals are electronic representations of sound waves—longitudinal waves which travel through air, consisting ...
used to alter the sound of amplified electric musical instruments, usually by increasing their
gain Gain or GAIN may refer to: Science and technology * Gain (electronics), an electronics and signal processing term * Antenna gain * Gain (laser), the amplification involved in laser emission * Gain (projection screens) * Information gain in de ...
, producing a "fuzzy", "growling", or "gritty" tone. Distortion is most commonly used with the
electric guitar An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar (however combinations of the two - a semi-acoustic guitar and an electric acoustic gui ...
, but may also be used with other electric instruments such as
electric bass The bass guitar, electric bass or simply bass (), is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck The ...
,
electric piano An electric piano is a musical instrument which produces sounds when a performer presses the keys of a piano-style musical keyboard. Pressing keys causes mechanical hammers to strike metal strings, metal reeds or wire tines, leading to vibrations ...
,
synthesizer A synthesizer (also spelled synthesiser) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and ...
and
Hammond organ The Hammond organ is an electric organ invented by Laurens Hammond and John M. Hanert and first manufactured in 1935. Multiple models have been produced, most of which use sliding drawbars to vary sounds. Until 1975, Hammond organs generated s ...
. Guitarists playing
electric blues Electric blues refers to any type of blues music distinguished by the use of electric amplifier, amplification for musical instruments. The guitar was the first instrument to be popularly amplified and used by early pioneers T-Bone Walker in the ...
originally obtained an overdriven sound by turning up their
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...
-powered
guitar amplifier 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 a ...
s to high volumes, which caused the signal to
distort 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 ...
. While overdriven tube amps are still used to obtain overdrive, especially in genres like blues and
rockabilly Rockabilly is one of the earliest styles of rock and roll music. It dates back to the early 1950s in the United States, especially the Southern United States, South. As a genre it blends the sound of Western music (North America), Western music ...
, a number of 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 Rock music is a broad genre of popular music that originated as " rock and roll" in the United States in the late 1940s and early 1950s, developing into a range of different styles in the mid-1960s and later, particularly in the United States an ...
genres, notably
hard rock Hard rock or heavy rock is a loosely defined subgenre of rock music typified by aggressive vocals and distorted electric guitars. Hard rock began in the mid-1960s with the garage, psychedelic and blues rock movements. Some of the earliest hard ...
, punk rock,
hardcore punk Hardcore punk (also known as simply hardcore) is a punk rock music genre and subculture that originated in the late 1970s. It is generally faster, harder, and more aggressive than other forms of punk rock. Its roots can be traced to earlier punk ...
,
acid rock Acid rock is a loosely defined type of rock music that evolved out of the mid-1960s garage punk movement and helped launch the psychedelic subculture. Named after lysergic acid diethylamide (LSD), the style is generally defined by heavy, di ...
, and
heavy metal music 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 ...
, while the use of distorted bass has been essential in a genre of hip hop music and
alternative hip hop Alternative hip hop (also known as alternative rap) is a subgenre of hip hop music that encompasses a wide range of styles that are not typically identified as mainstream. AllMusic defines it as comprising " hip hop groups that refuse to confor ...
known as " SoundCloud rap". The effects alter the instrument sound by
clipping Clipping may refer to: Words * Clipping (morphology), the formation of a new word by shortening it, e.g. "ad" from "advertisement" * Clipping (phonetics), shortening the articulation of a speech sound, usually a vowel * Clipping (publications) ...
the signal (pushing it past its maximum, which shears off the peaks and troughs of the signal waves), adding sustain and harmonic and inharmonic
overtone An overtone is any resonant frequency above the fundamental frequency of a sound. (An overtone may or may not be a harmonic) In other words, overtones are all pitches higher than the lowest pitch within an individual sound; the fundamental i ...
s 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. Distortion, overdrive, and fuzz can be produced by
effects pedals An effects unit or effects pedal is an electronic device that alters the sound of a musical instrument or other audio source through audio signal processing. Common effects include distortion/overdrive, often used with electric guitar in ele ...
, rackmounts,
pre-amplifier A preamplifier, also known as a preamp, is an electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier an ...
s,
power amplifier An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspea ...
s (a potentially speaker-blowing approach),
speaker Speaker may refer to: Society and politics * Speaker (politics), the presiding officer in a legislative assembly * Public speaker, one who gives a speech or lecture * A person producing speech: the producer of a given utterance, especially: ** I ...
s and (since the 2000s) by digital
amplifier modeling Amplifier modeling (also known as amp modeling or amp emulation) is the process of emulating a physical amplifier such as a guitar amplifier. Amplifier modeling often seeks to recreate the sound of one or more specific models of vacuum tube ampl ...
devices and
audio software Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to: Sound * Audio signal, an electrical representation of sound *Audio frequency, a frequency in the audio spectrum *Digital audio, representation of soun ...
.Aikin, Jim (2004)
''Power Tools for Synthesizer Programming''
Hal Leonard. p. 171.
These effects are used with
electric guitar An electric guitar is a guitar that requires external amplification in order to be heard at typical performance volumes, unlike a standard acoustic guitar (however combinations of the two - a semi-acoustic guitar and an electric acoustic gui ...
s,
electric bass The bass guitar, electric bass or simply bass (), is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck The ...
es (
fuzz bass Fuzz bass is a style of playing the electric bass or modifying its signal that produces a buzzy, distorted, overdriven sound, as the name implies. Overdriving a bass signal significantly changes the timbre, adds higher overtones (harmonics) ...
),
electronic keyboard An electronic keyboard, portable keyboard, or digital keyboard is an electronic musical instrument, an electronic derivative of keyboard instruments. Electronic keyboards include synthesizers, digital pianos, stage pianos, electronic organs an ...
s, and more rarely as a special effect with vocals. While distortion is often created intentionally as a musical effect, musicians and sound engineers sometimes take steps to avoid distortion, particularly when using
PA system A public address system (or PA system) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound sou ...
s to amplify vocals or when playing back prerecorded music.


History


Early uses of amplified distortion

The first guitar amplifiers were relatively low-fidelity, and would often produce distortion when their volume (
gain Gain or GAIN may refer to: Science and technology * Gain (electronics), an electronics and signal processing term * Antenna gain * Gain (laser), the amplification involved in laser emission * Gain (projection screens) * Information gain in de ...
) was increased beyond their design limit or if they sustained minor damage. Around 1945, Western-swing guitarist
Junior Barnard Lester Robert Barnard (December 17, 1920 – April 15, 1951), known as Junior Barnard, was an American Western swing guitarist who was a member of Bob Wills and his Texas Playboys. He was among the first electric guitarists to create a guitar ef ...
began experimenting with a rudimentary humbucker pick-up and a small amplifier to obtain his signature "low-down and dirty" bluesy sound. Many
electric blues Electric blues refers to any type of blues music distinguished by the use of electric amplifier, amplification for musical instruments. The guitar was the first instrument to be popularly amplified and used by early pioneers T-Bone Walker in the ...
guitarists, including
Chicago blues Chicago blues is a form of blues music developed in Chicago, Illinois. It is based on earlier blues idioms, such as Delta blues, but performed in an urban style. It developed alongside the Great Migration of the first half of the twentieth cent ...
men such as
Elmore James Elmore James ( Brooks; January 27, 1918 – May 24, 1963) was an American blues guitarist, singer, songwriter, and bandleader. Noted for his use of loud amplification and his stirring voice, James was inducted into the Rock and Roll Hall of Fam ...
and
Buddy Guy George "Buddy" Guy (born July 30, 1936) is an American blues guitarist and singer. He is an exponent of Chicago blues who has influenced generations of guitarists including Eric Clapton, Jimi Hendrix, Jimmy Page, Keith Richards, Stevie Ray V ...
, experimented in order to get a guitar sound that paralleled the rawness of
blues Blues is a music genre and musical form which originated in the Deep South of the United States around the 1860s. Blues incorporated spirituals, work songs, field hollers, shouts, chants, and rhymed simple narrative ballads from the Afr ...
singers such as
Muddy Waters McKinley Morganfield (April 4, 1913 April 30, 1983), known professionally as Muddy Waters, was an American blues singer and musician who was an important figure in the post-war blues scene, and is often cited as the "father of modern Chicago b ...
and
Howlin' Wolf Chester Arthur Burnett (June 10, 1910January 10, 1976), better known by his stage name Howlin' Wolf, was an American blues singer and guitarist. He is regarded as one of the most influential blues musicians of all time. Over a four-decade care ...
, replacing often their originals with the powerful Valco "Chicagoan" pick-ups, originally created for lap-steel, to obtain a louder and fatter tone. In early
rock music Rock music is a broad genre of popular music that originated as " rock and roll" in the United States in the late 1940s and early 1950s, developing into a range of different styles in the mid-1960s and later, particularly in the United States an ...
,
Goree Carter Goree Chester Carter or Christer Carter (December 31, 1930 – December 29, 1990), was an American singer, guitarist, drummer, and songwriter. He was also credited with the stage names Little T-Bone, Rocky Thompson and Gory Carter, and record ...
's "Rock Awhile" (1949) featured an over-driven electric guitar style similar to that of Chuck Berry several years later, Robert Palmer, "Church of the Sonic Guitar", pp. 13-38 in Anthony DeCurtis, ''Present Tense'',
Duke University Press Duke University Press is an academic publisher and university press affiliated with Duke University. It was founded in 1921 by William T. Laprade as The Trinity College Press. (Duke University was initially called Trinity College). In 1926 Du ...
, 1992, p. 19. .
as well as
Joe Hill Louis Joe Hill Louis (September 23, 1921 – August 5, 1957), born Lester Hill, was an American singer, guitarist, harmonica player and one-man band. He was one of a small number of one-man blues bands (along with fellow Memphis bluesman Doctor Ross) ...
' " Boogie in the Park" (1950). In the early 1950s, guitar distortion sounds started to evolve based on sounds created earlier in the decade by accidental damage to amps, such as in the popular early recording of the 1951 Ike Turner and the Kings of Rhythm song "
Rocket 88 "Rocket 88" (originally stylized as Rocket "88") is a song that was first recorded in Memphis, Tennessee, in March 1951. The recording was credited to " Jackie Brenston and his Delta Cats", who were actually Ike Turner and his Kings of Rhythm. T ...
", where guitarist
Willie Kizart Willie Kizart (January 4, 1932 – September 2, 1998) was an American electric blues guitarist best known for being a member of Ike Turner's Kings of Rhythm in the 1950s. Kizart played guitar on "Rocket 88" in 1951, which is considered by some acc ...
used a vacuum tube amplifier that had a speaker cone slightly damaged in transport. Electric guitarists began intentionally "doctoring" amplifiers and speakers in order to emulate this form of distortion. Electric blues guitarist Willie Johnson of
Howlin' Wolf Chester Arthur Burnett (June 10, 1910January 10, 1976), better known by his stage name Howlin' Wolf, was an American blues singer and guitarist. He is regarded as one of the most influential blues musicians of all time. Over a four-decade care ...
′s band began deliberately increasing gain beyond its intended levels to produce "warm" distorted sounds.
Guitar Slim Eddie Jones (December 10, 1926 – February 7, 1959), better known as Guitar Slim, was an American guitarist in the 1940s and 1950s, best known for the million-selling song " The Things That I Used to Do", for Specialty Records. It is listed in t ...
also experimented with distorted overtones, which can be heard in his hit
electric blues Electric blues refers to any type of blues music distinguished by the use of electric amplifier, amplification for musical instruments. The guitar was the first instrument to be popularly amplified and used by early pioneers T-Bone Walker in the ...
song "
The Things That I Used to Do "The Things That I Used to Do" is a blues standard written by Guitar Slim. He recorded it in New Orleans, where the young Ray Charles arranged and produced the session. Specialty Records released the song as a single in 1953 and it became a bests ...
" (1953).
Chuck Berry Charles Edward Anderson Berry (October 18, 1926 – March 18, 2017) was an American singer, songwriter and guitarist who pioneered rock and roll. Nicknamed the " Father of Rock and Roll", he refined and developed rhythm and blues into th ...
's 1955 classic "
Maybellene "Maybellene" is a rock and roll song. It was written and recorded in 1955 by Chuck Berry, adapted in part from the Western swing fiddle tune "Ida Red". Berry's song told the story of a hot rod race and a broken romance, the lyrics describing ...
" features a guitar solo with warm
overtone An overtone is any resonant frequency above the fundamental frequency of a sound. (An overtone may or may not be a harmonic) In other words, overtones are all pitches higher than the lowest pitch within an individual sound; the fundamental i ...
s created by his small
valve amplifier A valve amplifier or tube amplifier is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a signal. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by sol ...
.
Pat Hare Auburn "Pat" Hare was a Memphis electric blues guitarist and singer. His heavily distortion (music), distorted, power chord–driven electric guitar performances in the early 1950s is considered an important precursor of heavy metal music.Robert P ...
produced heavily distorted
power chord A power chord (also fifth chord) is a colloquial name for a chord in guitar music, especially electric guitar, that consists of the root note and the fifth, as well as possibly octaves of those notes. Power chords are commonly played on am ...
s on his electric guitar for records such as
James Cotton James Henry Cotton (July 1, 1935 – March 16, 2017) was an American blues harmonica player, singer and songwriter, who performed and recorded with many fellow blues artists and with his own band. He also played drums early in his career. ...
's " Cotton Crop Blues" (1954) as well as his own "I'm Gonna Murder My Baby" (1954), creating "a grittier, nastier, more ferocious electric guitar sound," Robert Palmer, "Church of the Sonic Guitar", pp. 13-38 in Anthony DeCurtis, ''Present Tense'',
Duke University Press Duke University Press is an academic publisher and university press affiliated with Duke University. It was founded in 1921 by William T. Laprade as The Trinity College Press. (Duke University was initially called Trinity College). In 1926 Du ...
, 1992, pp. 24-27. .
accomplished by turning the volume knob on his amplifier "all the way to the right until the speaker was screaming." In 1956, guitarist Paul Burlison of the
Johnny Burnette Trio John Joseph Burnette (March 25, 1934 – August 14, 1964) was an American singer and songwriter of rockabilly and pop music. In 1952, Johnny and his brother, Dorsey Burnette, and their mutual friend Paul Burlison formed the band that became k ...
deliberately dislodged a
vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...
in his amplifier to record " The Train Kept A-Rollin" after a reviewer raved about the sound Burlison's damaged amplifier produced during a live performance. According to other sources Burlison's amp had a partially broken loudspeaker cone. Pop-oriented producers were horrified by that eerie "two-tone" sound, quite clean on trebles but strongly distorted on basses, but Burnette insisted to publish the sessions, arguing that "that guitar sounds like a nice horn section". In the late 1950s, Guitarist Link Wray began intentionally manipulating his amplifiers' vacuum tubes to create a "noisy" and "dirty" sound for his solos after a similarly accidental discovery. Wray also poked holes in his speaker cones with pencils to further distort his tone, used electronic echo chambers (then usually employed by singers), the recent powerful and "fat" Gibson humbucker pickups, and controlled "feedback" (
Larsen effect Audio feedback (also known as acoustic feedback, simply as feedback) is a positive feedback situation which may occur when an acoustic path exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for examp ...
). The resultant sound can be heard on his highly influential 1958
instrumental An instrumental is a recording normally without any vocals, although it might include some inarticulate vocals, such as shouted backup vocals in a big band setting. Through semantic widening, a broader sense of the word song may refer to instru ...
, " Rumble" and Rawhide.


1960s: fuzz, distortion, and introduction of commercial devices

In 1961,
Grady Martin Thomas Grady Martin (January 17, 1929 – December 3, 2001) was an American session guitarist in country music and rockabilly. A member of The Nashville A-Team, he played guitar on hits such as Marty Robbins' " El Paso", Loretta Lynn's " Co ...
scored a hit with a fuzzy tone caused by a faulty
preamplifier A preamplifier, also known as a preamp, is an electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier an ...
that distorted his guitar playing on the
Marty Robbins Martin David Robinson (September 26, 1925 – December 8, 1982), known professionally as Marty Robbins, was an American singer, songwriter, actor, multi-instrumentalist, and NASCAR racing driver. Robbins was one of the most popular and suc ...
song " Don't Worry". Later that year Martin recorded an instrumental tune under his own name, using the same faulty preamp. The song, on the Decca label, was called "The Fuzz." Martin is generally credited as the discoverer of the "fuzz effect." The
recording engineer 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, ...
from Martin's sessions, Glenn Snoddy, partnered with fellow WSM
radio engineer Broadcast engineering is the field of electrical engineering, and now to some extent computer engineering and information technology, which deals with radio and television broadcasting. Audio engineering and RF engineering are also essential ...
Revis V. Hobbs to design and build a stand-alone device that would intentionally create the fuzzy effect. The two engineers sold their circuit to
Gibson Gibson may refer to: People * Gibson (surname) Businesses * Gibson Brands, Inc., an American manufacturer of guitars, other musical instruments, and audio equipment * Gibson Technology, and English automotive and motorsport company based * Gi ...
, who introduced it as the Maestro FZ-1 Fuzz-Tone in 1962, one of the first commercially-successful mass-produced guitar pedals. Shortly thereafter, the American instrumental rock band
The Ventures The Ventures are an American instrumental rock band formed in Tacoma, Washington, in 1958, by Don Wilson and Bob Bogle. The band, which was a quartet for most of its existence, helped to popularize the electric guitar across the world during the ...
asked their friend, session musician and electronics enthusiast Orville "Red" Rhodes for help recreating the Grady Martin "fuzz" sound. Rhodes offered The Ventures a fuzzbox he had made, which they used to record "2000 Pound Bee" in 1962. In 1964, a fuzzy and somewhat distorted sound gained widespread popularity after guitarist
Dave Davies David Russell Gordon Davies (born 3 February 1947) is an English guitarist, singer and songwriter. He was the lead guitarist and backing vocalist for the English rock band the Kinks, which also featured his elder brother Ray Davies. He was in ...
of
The Kinks The Kinks were an English rock band formed in Muswell Hill, north London, in 1963 by brothers Ray and Dave Davies. They are regarded as one of the most influential rock bands of the 1960s. The band emerged during the height of British rhythm ...
used a razor blade to slash his speaker cones for the band's single "
You Really Got Me "You Really Got Me" is a song written by Ray Davies for English rock band the Kinks. The song, originally performed in a more blues-oriented style, was inspired by artists such as Lead Belly and Big Bill Broonzy. Two versions of the song were ...
". In May 1965
Keith Richards Keith Richards (born 18 December 1943), often referred to during the 1960s and 1970s as "Keith Richard", is an English musician and songwriter who has achieved international fame as the co-founder, guitarist, secondary vocalist, and co-princi ...
used a Maestro FZ-1 Fuzz-Tone to record "
(I Can't Get No) Satisfaction "(I Can't Get No) Satisfaction" is a song recorded by the English rock band the Rolling Stones. A product of Mick Jagger and Keith Richards' songwriting partnership, it features a guitar riff by Richards that opens and drives the song. The riff ...
". The song's success greatly boosted sales of the device, and all available stock sold out by the end of 1965. Other early fuzzboxes include the
Mosrite Mosrite is an American guitar manufacturing company, based in Bakersfield, California, from the late 1950s to the early 1990s. Founded by Semie Moseley, Mosrite guitars were played by many rock and roll and country artists. Mosrite guitars wer ...
FuzzRITE and Arbiter Group
Fuzz Face The Fuzz Face is an effects pedal for electric guitar, used also by some electric bass players. It is designed to produce a distorted sound referred to as "fuzz", originally achieved through accident such as broken electrical components or damaged ...
used by
Jimi Hendrix James Marshall "Jimi" Hendrix (born Johnny Allen Hendrix; November 27, 1942September 18, 1970) was an American guitarist, singer and songwriter. Although his mainstream career spanned only four years, he is widely regarded as one of the most ...
, the
Electro-Harmonix Electro-Harmonix (also commonly referred to as EHX) is a New York City-based company that makes electronic audio processors and sells rebranded vacuum tubes. The company was founded by Mike Matthews in 1968. It is best known for a series of gu ...
Big Muff Pi The Big Muff Pi (π), often known simply as the Big Muff, is a fuzzbox produced in New York City by the Electro-Harmonix company, along with their Russian sister company Sovtek, primarily for use with the electric guitar. It is used by bassists ...
used by Hendrix and
Carlos Santana Carlos Humberto Santana Barragán (; born July 20, 1947) is an American guitarist who rose to fame in the late 1960s and early 1970s with his band Santana, which pioneered a fusion of Rock and roll and Latin American jazz. Its sound featured ...
, and the Vox Tone Bender used by
Paul McCartney Sir James Paul McCartney (born 18 June 1942) is an English singer, songwriter and musician who gained worldwide fame with the Beatles, for whom he played bass guitar and shared primary songwriting and lead vocal duties with John Lennon. One ...
to play
fuzz bass Fuzz bass is a style of playing the electric bass or modifying its signal that produces a buzzy, distorted, overdriven sound, as the name implies. Overdriving a bass signal significantly changes the timbre, adds higher overtones (harmonics) ...
on "
Think for Yourself "Think for Yourself" is a song by the English rock band the Beatles from their 1965 album ''Rubber Soul''. It was written by George Harrison, the band's lead guitarist, and, together with "If I Needed Someone", marked the start of his emergenc ...
" and other Beatles recordings. In 1966, Jim Marshall of the British company
Marshall Amplification Marshall is a British company that designs and manufactures music amplifiers, speaker cabinets, brands personal headphones and earphones, drums and bongos. The company also owns a record label called Marshall Records. It was founded in London ...
began modifying the electronic circuitry of his amplifiers so as to achieve a "brighter, louder" sound and fuller distortion capabilities. Also in 1966,
Syd Barrett Roger Keith "Syd" Barrett (6 January 1946 – 7 July 2006) was an English singer, songwriter, and musician who co-founded the rock band Pink Floyd in 1965. Barrett was their original frontman and primary songwriter, becoming known for his ...
of
Pink Floyd Pink Floyd are an English rock band formed in London in 1965. Gaining an early following as one of the first British psychedelic music, psychedelic groups, they were distinguished by their extended compositions, sonic experimentation, philo ...
created the song
Interstellar Overdrive "Interstellar Overdrive" is an instrumental composition written and performed by Pink Floyd. The song was written in 1966 and is on their 1967 debut album, '' The Piper at the Gates of Dawn'', clocking in at almost ten minutes in length. The so ...
, a song made entirely in electric distortion. It was released a year later in modified form on their debut album
The Piper at the Gates of Dawn ''The Piper at the Gates of Dawn'' is the debut studio album by English rock band Pink Floyd, released on 5 August 1967 by EMI Columbia. It is the only Pink Floyd album made under the leadership of founding member Syd Barrett (lead vocals, g ...
. In the late 1960s and early 1970s
hard rock Hard rock or heavy rock is a loosely defined subgenre of rock music typified by aggressive vocals and distorted electric guitars. Hard rock began in the mid-1960s with the garage, psychedelic and blues rock movements. Some of the earliest hard ...
bands such as
Deep Purple Deep Purple are an English rock band formed in London in 1968. They are considered to be among the pioneers of heavy metal music, heavy metal and modern hard rock music, but their musical style has changed over the course of its existence. Ori ...
,
Led Zeppelin Led Zeppelin were an English rock band formed in London in 1968. The group comprised vocalist Robert Plant, guitarist Jimmy Page, bassist/keyboardist John Paul Jones, and drummer John Bonham. With a heavy, guitar-driven sound, they are ci ...
and
Black Sabbath Black Sabbath were an English rock music, rock band formed in Birmingham in 1968 by guitarist Tony Iommi, drummer Bill Ward (musician), Bill Ward, bassist Geezer Butler and vocalist Ozzy Osbourne. They are often cited as pioneers of heavy met ...
forged what would eventually become the heavy metal sound through a combined use of high volumes and heavy distortion.


Theory and circuits

The word
distortion 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 ...
refers to any modification of
wave form In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (r ...
of a
signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...
, but in music it is used to refer to nonlinear distortion (excluding filters) and particularly to the introduction of new frequencies by memoryless nonlinearities. In music the different forms of linear distortion have specific names describing them. The simplest of these is a distortion process known as "volume adjustment", which involves distorting the amplitude of a sound wave in a proportional (or ‘linear’) way in order to increase or decrease the volume of the sound without affecting the tone quality. In the context of music, the most common source of (nonlinear) distortion is
clipping Clipping may refer to: Words * Clipping (morphology), the formation of a new word by shortening it, e.g. "ad" from "advertisement" * Clipping (phonetics), shortening the articulation of a speech sound, usually a vowel * Clipping (publications) ...
in amplifier circuits and is most commonly known as overdrive. Clipping is a
non-linear In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other ...
process that produces
frequencies Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
not originally present in the
audio signal An audio signal is a representation of sound, typically using either a changing level of electrical voltage for analog signals, or a series of binary numbers for digital signals. Audio signals have frequencies in the audio frequency range of r ...
. These frequencies can be
harmonic A harmonic is a wave with a frequency that is a positive integer multiple of the ''fundamental frequency'', the frequency of the original periodic signal, such as a sinusoidal wave. The original signal is also called the ''1st harmonic'', the ...
overtones, meaning they are whole number multiples of one of the signal's original frequencies, or "inharmonic", resulting from general
intermodulation distortion Intermodulation (IM) or intermodulation distortion (IMD) is the amplitude modulation of Signal (electrical engineering), signals containing two or more different frequencies, caused by non-linear, nonlinearities or time variance in a system. ...
. The same nonlinear device will produce both types of distortion, depending on the input signal. Intermodulation occurs whenever the input frequencies are not already harmonically related. For instance, playing a
power chord A power chord (also fifth chord) is a colloquial name for a chord in guitar music, especially electric guitar, that consists of the root note and the fifth, as well as possibly octaves of those notes. Power chords are commonly played on am ...
through distortion results in intermodulation that produces new subharmonics. "Soft clipping" gradually flattens the peaks of a signal which creates a number of higher
harmonics A harmonic is a wave with a frequency that is a positive integer multiple of the '' fundamental frequency'', the frequency of the original periodic signal, such as a sinusoidal wave. The original signal is also called the ''1st harmonic'', ...
which share a harmonic relationship with the original tone. "Hard clipping" flattens peaks abruptly, resulting in higher power in higher harmonics. As clipping increases, a tone input progressively begins to resemble a
square wave A square wave is a non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same duration at minimum and maximum. In an ideal square wave, the transitions b ...
which has odd number harmonics. This is generally described as sounding "harsh". Distortion and overdrive circuits each 'clip' the signal before it reaches the main amplifier (clean boost circuits do not necessarily create 'clipping') as well as boost signals to levels that cause distortion to occur at the main amplifier's front end stage (by exceeding the ordinary input signal amplitude, thus ''overdriving'' the amplifier) Note : product names may not accurately reflect type of circuit involved - see above. A fuzz box alters an audio signal until it is nearly a square wave and adds complex overtones by way of a
frequency multiplier In electronics, a frequency multiplier is an electronic circuit that generates an output signal and that output frequency is a harmonic (multiple) of its input frequency. Frequency multipliers consist of a nonlinear circuit that distorts the in ...
.


Valve overdrive

Vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type kn ...
or "valve" distortion is achieved by "overdriving" the valves in an amplifier. In layman's terms, overdriving is pushing the tubes beyond their normal rated maximum. Valve amplifiers—particularly those using class-A
triode A triode is an electronic amplifying vacuum tube (or ''valve'' in British English) consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, and a plate (anode). Developed from Lee De Forest's 19 ...
s—tend to produce asymmetric soft clipping that creates both even and odd harmonics. The increase in even harmonics is considered to create "warm"-sounding overdrive effects. A basic triode valve (tube) contains a
cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...
, a plate and a grid. When a positive
voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
is applied to the plate, a
current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (stre ...
of negatively charged electrons flows to it from the heated cathode through the grid. This increases the voltage of the
audio signal An audio signal is a representation of sound, typically using either a changing level of electrical voltage for analog signals, or a series of binary numbers for digital signals. Audio signals have frequencies in the audio frequency range of r ...
, amplifying its volume. The grid regulates the extent to which plate voltage is increased. A small negative voltage applied to the grid causes a large decrease in plate voltage. Valve amplification is more or less linear—meaning the parameters (amplitude, frequency, phase) of the amplified signal are proportional to the input signal—so long as the voltage of the input signal does not exceed the valve's "linear region of operation". The linear region falls between # The saturation region: the voltages at which plate current stops responding to positive increases in grid voltage and # The cutoff region: the voltages at which the charge of the grid is too negative for electrons to flow to the plate. If a valve is biased within the linear region and the input signal's voltage exceeds this region, overdrive and non-linear clipping will occur. Multiple stages of valve gain/clipping can be "cascaded" to produce a thicker and more complex distortion sound. In layperson's terms, a musician will plug a fuzz pedal into a tube amp that is being "cranked" to a clipping "overdriven" condition; as such, the musician will get the distortion from the fuzz which is then distorted further by the amp. During the 1990s, some Seattle grunge guitarists chained together as many as four fuzz pedals to create a thick "
wall of sound The Wall of Sound (also called the Spector Sound) is a music production formula developed by American record producer Phil Spector at Gold Star Studios, in the 1960s, with assistance from engineer Larry Levine and the conglomerate of session m ...
" of distortion. In some modern valve effects, the "dirty" or "gritty" tone is actually achieved not by high voltage, but by running the circuit at voltages that are too low for the circuit components, resulting in greater non-linearity and distortion. These designs are referred to as "starved plate" configurations, and result in an "amp death" sound.


Solid-state distortion

Solid-state Solid state, or solid matter, is one of the four fundamental states of matter. Solid state may also refer to: Electronics * Solid-state electronics, circuits built of solid materials * Solid state ionics, study of ionic conductors and their use ...
amplifiers incorporating
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
s and/or
op amp An operational amplifier (often op amp or opamp) is a DC-coupled high- gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential (relative to ...
s can be made to produce hard clipping. When symmetrical, this adds additional high-amplitude odd harmonics, creating a "dirty" or "gritty" tone. When asymmetrical, it produces both even and odd harmonics. Electronically, this is usually achieved by either amplifying the signal to a point where it is clipped by the DC voltage limitation of the power supply rail, or by clipping the signal with diodes. Many solid-state distortion devices attempt to emulate the sound of overdriven vacuum valves using additional solid-state circuitry. Some amplifiers (notably the Marshall JCM 900) utilize hybrid designs that employ both valve and solid-state components.


Approaches

Guitar distortion can be produced by many components of the guitar's signal path, including effects pedals, the pre-amplifier, power amplifier, and speakers. Many players use a combination of these to obtain their "signature" tone.


Pre-amplifier distortion

The
pre-amplifier A preamplifier, also known as a preamp, is an electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier an ...
section of a guitar amplifier serves to amplify a weak instrument signal to a level that can drive the power amplifier. It often also contains circuitry to shape the tone of the instrument, including equalization and
gain Gain or GAIN may refer to: Science and technology * Gain (electronics), an electronics and signal processing term * Antenna gain * Gain (laser), the amplification involved in laser emission * Gain (projection screens) * Information gain in de ...
controls. Often multiple cascading gain/clipping stages are employed to generate distortion. Because the first component in a valve amplifier is a valve gain stage, the output level of the preceding elements of the signal chain has a strong influence on the distortion created by that stage. The output level of the guitar's pickups, the setting of the guitar's volume knob, how hard the strings are plucked, and the use of volume-boosting effects pedals can drive this stage harder and create more distortion. During the 1980s and 1990s, most valve amps featured a "master volume" control, an adjustable attenuator between the preamp section and the power amp. When the preamp volume is set high to generate high distortion levels, the master volume lowered, keeping the output volume at manageable levels.


Overdrive/distortion pedals

Analog overdrive/distortion pedals work on similar principles to preamplifier distortion. Because most effects pedals are designed to operate from battery voltages, using vacuum tubes to generate distortion and overdrive is impractical; instead, most pedals use solid-state transistors, op-amps and diodes. Classic examples of overdrive/distortion pedals include the Boss OD series (overdrives), the
Ibanez Tube Screamer The Ibanez Tube Screamer (TS808/TS9) is a guitar overdrive pedal, made by Ibanez. The pedal has a characteristic mid-boosted tone popular with blues, rock and metal players. The Tube Screamer has been used by many guitarists to create their signa ...
(an overdrive), the Electro-Harmonix Big Muff Pi (a fuzz box) and the
Pro Co RAT The Pro Co "The RAT" is a distortion pedal produced by Pro Co Sound. The original RAT was developed in the basement of Pro Co's Kalamazoo, Michigan facility in 1978. Numerous variations of the original RAT pedal are still being produced today. The ...
(a distortion). Typically, "overdrive" pedals are designed to produce sounds associated with classic rock or blues, with "distortion" pedals producing the "high gain, scooped mids" sounds associated with heavy metal; fuzz boxes are designed to emulate the distinctive sound of the earliest overdrive pedals such as the
Big Muff The Big Muff Pi (π), often known simply as the Big Muff, is a fuzzbox produced in New York City by the Electro-Harmonix company, along with their Russian sister company Sovtek, primarily for use with the electric guitar. It is used by bassist ...
and the
Fuzz Face The Fuzz Face is an effects pedal for electric guitar, used also by some electric bass players. It is designed to produce a distorted sound referred to as "fuzz", originally achieved through accident such as broken electrical components or damaged ...
. Most overdrive/distortion pedals can be used in two ways: a pedal can be used as a "boost" with an already overdriven amplifier to drive it further into saturation and "color" the tone, or it can be used with a completely clean amplifier to generate the whole overdrive/distortion effect. With care—and with appropriately chosen pedals—it is possible to "stack" multiple overdrive/distortion pedals together, allowing one pedal to act as a 'boost' for another. Fuzz boxes and other heavy distortions can produce unwanted dissonances when playing chords. To get around this, guitar players (and keyboard players) using these effects may restrict their playing to single notes and simple "
power chord A power chord (also fifth chord) is a colloquial name for a chord in guitar music, especially electric guitar, that consists of the root note and the fifth, as well as possibly octaves of those notes. Power chords are commonly played on am ...
s" (root, fifth, and octave). Indeed, with the most extreme fuzz pedals, players may choose to play mostly single notes, because the fuzz can make even single notes sound very thick and heavy. Heavy distortion also tends to limit the player's control of dynamics (loudness and softness)—similar to the limitations imposed on a
Hammond organ The Hammond organ is an electric organ invented by Laurens Hammond and John M. Hanert and first manufactured in 1935. Multiple models have been produced, most of which use sliding drawbars to vary sounds. Until 1975, Hammond organs generated s ...
player (Hammond organ does not produce louder or softer sounds depending on how hard or soft the performer plays the keys; however, the performer can still control the volume with drawbars and the expression pedal). Heavy metal music has evolved around these restrictions, using complex rhythms and timing for expression and excitement. Lighter distortions and overdrives can be used with triadic chords and seventh chords; as well, lighter overdrive allows more control of dynamics.


Power amplifier distortion

Power valves (tubes) can be overdriven in the same way that pre-amplifier valves can, but because these valves are designed to output more power, the distortion and character they add to the guitar's tone is unique. During the 1960s to early 1970s, distortion was primarily created by overdriving the power valves. Because they have become accustomed to this sound , many guitar players favour this type of distortion, and thus set their amps to maximum levels in order to drive the power section hard. Many valve-based amplifiers in common use have a push-pull output configuration in their power section, with matched pairs of tubes driving the
output transformer A variety of types of electrical transformer are made for different purposes. Despite their design differences, the various types employ the same basic principle as discovered in 1831 by Michael Faraday, and share several key functional part ...
. Power amplifier distortion is normally entirely symmetric, generating predominantly odd-order harmonics. Because driving the power valves this hard also means maximum volume, which can be difficult to manage in a small recording or rehearsal space, many solutions have emerged that in some way divert some of this power valve output from the speakers, and allow the player to generate power valve distortion without excessive volume. These include built-in or separate power attenuators and power-supply-based power attenuation, such as a VVR, or Variable Voltage Regulator to drop the voltage on the valves' plates, to increase distortion whilst lowering volume. Guitarists such as Eddie Van Halen have been known to use variacs before VVR technology was invented. Lower-power valve amps (such as a quarter-watt or less), speaker isolation cabinets, and low-efficiency guitar speakers are also used to tame the volume. Power-valve distortion can also be produced in a dedicated rackmount valve power amp. A modular rackmount setup often involves a
rackmount A 19-inch rack is a standardized frame or enclosure for mounting multiple electronic equipment modules. Each module has a front panel that is wide. The 19 inch dimension includes the edges or "ears" that protrude from each side of the equ ...
preamp, a rackmount valve power amp, and a rackmount
dummy load A dummy load is a device used to simulate an electrical load, usually for testing purposes. In radio a dummy antenna is connected to the output of a radio transmitter and electrically simulates an antenna, to allow the transmitter to be adjust ...
to attenuate the output to desired volume levels. Some effects pedals internally produce power-valve distortion, including an optional dummy load for use as a power-valve distortion pedal. Such effects units can use a preamp valve such as the 12AX7 in a power-valve circuit configuration (as in the Stephenson's Stage Hog), or use a conventional power valve, such as the
EL84 The EL84 is a vacuum tube of the power pentode type. It is used in the power-output-stages of audio-amplifiers, most commonly now in guitar amplifiers, but originally in radios. The EL84 is smaller and more sensitive than the octal 6V6 that was ...
(as in the H&K Crunch Master compact tabletop unit). However, because these are usually placed before the pre-amplifier in the signal chain, they contribute to the overall tone in a different way. Power amplifier distortion may damage speakers. A Direct Inject signal can capture the power-tube distortion sound without the direct coloration of a guitar speaker and microphone. This DI signal can be blended with a miked guitar speaker, with the DI providing a more present, immediate, bright sound, and the miked guitar speaker providing a colored, remote, darker sound. The DI signal can be obtained from a DI jack on the guitar amp, or from the Line Out jack of a power attenuator.


Output transformer distortion

The output
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
sits between the power valves and the speaker, serving to match impedance. When a transformer's
ferromagnetic Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials ...
core becomes electromagnetically saturated a loss of inductance takes place, since the back E.M.F. is reliant on a change in flux in the core. As the core reaches saturation, the flux levels off and cannot increase any further. With no change in flux there is no back E.M.F. and hence no reflected impedance. The transformer and valve combination then generate large 3rd order harmonics. So long as the core does not go into saturation, the valves will clip naturally as they drop the available voltage across them. In single ended systems the output harmonics will be largely even ordered due to the valve's relatively non linear characteristics at large signal swings. This is only true however if the magnetic core does NOT saturate.


Power supply "sag"

Early valve amplifiers used unregulated power supplies. This was due to the high cost associated with high-quality
high-voltage High voltage electricity refers to electrical potential large enough to cause injury or damage. In certain industries, ''high voltage'' refers to voltage above a certain threshold. Equipment and Electrical conductor, conductors that carry high ...
power supplies. The typical
anode An anode is an electrode of a polarized electrical device through which conventional current enters the device. This contrasts with a cathode, an electrode of the device through which conventional current leaves the device. A common mnemonic is ...
(plate) supply was simply a
rectifier A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The reverse operation (converting DC to AC) is performed by an Power ...
, an inductor and a
capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...
. When the valve amplifier was operated at high
volume Volume is a measure of occupied three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch). The de ...
, the
power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a r ...
voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
would dip, reducing power output and causing signal attenuation and compression. This dipping effect is known as "sag", and is sought-after by some electric guitarists. Sag only occurs in
class-AB amplifiers In electronics, power amplifier classes are letter symbols applied to different power amplifier types. The class gives a broad indication of an amplifier's characteristics and performance. The classes are related to the time period that the active ...
. This is because, technically, sag results from more current being drawn from the power supply, causing a greater voltage drop over the
rectifier A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The reverse operation (converting DC to AC) is performed by an Power ...
valve. Class AB amplifiers draw the most power at both the maximum and minimum point of the signal, putting more stress on the power supply than class A, which only draws maximum power at the peak of the signal. As this effect is more pronounced with higher input signals, the harder "attack" of a note will be compressed more heavily than the lower-voltage "decay", making the latter seem louder and thereby improving
sustain In sound and music, an envelope describes how a sound changes over time. It may relate to elements such as amplitude (volume), frequencies (with the use of filters) or pitch. For example, a piano key, when struck and held, creates a near-immedi ...
. Additionally, because the level of compression is affected by input volume, the player can control it via their playing intensity: playing harder results in more compression or "sag". In contrast, modern amplifiers often use high-quality, well-regulated power supplies.


Speaker distortion

Guitar
loudspeakers A loudspeaker (commonly referred to as a speaker or speaker driver) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or "l ...
are designed differently from high fidelity stereo speakers or public address system speakers. While hi-fi and public address speakers are designed to reproduce the sound with as little distortion as possible, guitar speakers are usually designed so that they will shape or color the tone of the guitar, either by enhancing some frequencies or attenuating unwanted frequencies. When the power delivered to a guitar speaker approaches its maximum rated power, the speaker's performance degrades, causing the speaker to "break up", adding further distortion and colouration to the signal. Some speakers are designed to have much clean headroom, while others are designed to break up early to deliver grit and growl.


Amp modeling for distortion emulation

Guitar amp modeling devices and software can reproduce various guitar-specific distortion qualities that are associated with a range of popular "stomp box" pedals and amplifiers. Amp modeling devices typically use
digital signal processing Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are ...
to recreate the sound of plugging into analogue pedals and overdriven valve amplifiers. The most sophisticated devices allow the user to customize the simulated results of using different preamp, power-tube, speaker distortion, speaker cabinet, and microphone placement combinations. For example, a guitarist using a small amp modeling pedal could simulate the sound of plugging their electric guitar into a heavy vintage valve amplifier and a stack of 8 X 10" speaker cabinets.


Voicing with equalization

Guitar distortion is obtained and shaped at various points in the signal processing chain, including multiple stages of
preamp A preamplifier, also known as a preamp, is an electronic amplifier that converts a weak electrical signal into an output signal strong enough to be noise-tolerant and strong enough for further processing, or for sending to a power amplifier ...
distortion, power valve distortion, output and power transformer distortion, and guitar speaker distortion. Much of the distortion character or voicing is controlled by the
frequency response In signal processing and electronics, the frequency response of a system is the quantitative measure of the magnitude and phase of the output as a function of input frequency. The frequency response is widely used in the design and analysis of sy ...
before and after each distortion stage. This dependency of distortion voicing on frequency response can be heard in the effect that a
wah pedal A wah-wah pedal, or simply wah pedal, is a type of electric guitar effects pedal that alters the tone and frequencies of the guitar signal to create a distinctive sound, mimicking the human voice saying the onomatopoeic name "wah-wah". The ped ...
has on the subsequent distortion stage, or by using tone controls built into the guitar, the preamp or an EQ pedal to favor the bass or treble components of the guitar pickup signal prior to the first distortion stage. Some guitarists place an equalizer pedal after the distortion effect, to emphasize or de-emphasize different frequencies in the distorted signal. Increasing the bass and treble while reducing or eliminating the centre midrange (750 Hz) results in what is popularly known as a "scooped" sound (since the midrange frequencies are "scooped" out). Conversely, decreasing the bass while increasing the midrange and treble creates a punchy, harsher sound. Rolling off all of the treble produces a dark, heavy sound.


Avoiding distortion

While musicians intentionally create or add distortion to electric instrument signals or vocals to create a musical effect, there are some musical styles and musical applications where as little distortion as possible is sought. When DJs are playing recorded music in a
nightclub A nightclub (music club, discothèque, disco club, or simply club) is an entertainment venue during nighttime comprising a dance floor, lightshow, and a stage for live music or a disc jockey (DJ) who plays recorded music. Nightclubs gener ...
, they typically seek to reproduce the recordings with little or no distortion. In many musical styles, including
pop music Pop music is a genre of popular music that originated in its modern form during the mid-1950s in the United States and the United Kingdom. The terms ''popular music'' and ''pop music'' are often used interchangeably, although the former describe ...
,
country music Country (also called country and western) is a genre of popular music that originated in the Southern and Southwestern United States in the early 1920s. It primarily derives from blues, church music such as Southern gospel and spirituals, ...
and even genres where the electric guitars are almost always distorted, such as heavy metal, punk and hard rock, sound engineers usually take a number of steps to ensure that the vocals sounding through the sound reinforcement system are undistorted (the exception is the rare cases where distortion is purposely added to vocals in a song as a special effect). Sound engineers prevent unwanted, unintended distortion and clipping using a number of methods. They may reduce the gain on microphone preamplifiers on the
audio console A mixing console or mixing desk is an electronic device for mixing audio signals, used in sound recording and reproduction and sound reinforcement systems. Inputs to the console include microphones, signals from electric or electronic inst ...
; use attenuation "pads" (a button on audio console channel strips,
DI unit A DI unit (direct input or direct inject) is an electronic device typically used in recording studios and in sound reinforcement systems to connect a high- output impedance, line level, unbalanced output signal to a low-impedance, microphone leve ...
and some
bass amplifier A bass amplifier (also abbreviated to bass amp) is a musical instrument electronic device that uses electrical power to make lower-pitched instruments such as the bass guitar or double bass loud enough to be heard by the performers and audien ...
s); and use electronic
audio compressor Dynamic range compression (DRC) or simply compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, thus reducing or ''compressing'' an audio signal's dynamic range. Compression is ...
effects and limiters to prevent sudden volume peaks from vocal mics from causing unwanted distortion. Though some
bass guitar The bass guitar, electric bass or simply bass (), is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck and ...
players in metal and punk bands intentionally use
fuzz bass Fuzz bass is a style of playing the electric bass or modifying its signal that produces a buzzy, distorted, overdriven sound, as the name implies. Overdriving a bass signal significantly changes the timbre, adds higher overtones (harmonics) ...
to distort their bass sound, in other genres of music, such as pop,
big band A big band or jazz orchestra is a type of musical ensemble of jazz music that usually consists of ten or more musicians with four sections: saxophones, trumpets, trombones, and a rhythm section. Big bands originated during the early 1910s an ...
jazz and traditional
country music Country (also called country and western) is a genre of popular music that originated in the Southern and Southwestern United States in the early 1920s. It primarily derives from blues, church music such as Southern gospel and spirituals, ...
, bass players typically seek an undistorted bass sound. To obtain a clear, undistorted bass sound, professional bass players in these genres use high-powered amplifiers with a lot of " headroom" and they may also use audio compressors to prevent sudden volume peaks from causing distortion. In many cases, musicians playing
stage piano A stage piano is an electronic musical instrument designed for use in live performances on stage or in a studio, as well as for music recording in jazz and popular music. While stage pianos share some of the same features as digital pianos des ...
s or
synthesizer A synthesizer (also spelled synthesiser) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and ...
s use
keyboard amplifier A keyboard amplifier is a powered electronic amplifier and loudspeaker in a wooden speaker cabinet used for amplification of electronic keyboard instruments. Keyboard amplifiers are distinct from other types of amplification systems such as g ...
s that are designed to reproduce the audio signal with as little distortion as possible. The exceptions with keyboards are the
Hammond organ The Hammond organ is an electric organ invented by Laurens Hammond and John M. Hanert and first manufactured in 1935. Multiple models have been produced, most of which use sliding drawbars to vary sounds. Until 1975, Hammond organs generated s ...
as used in
blues Blues is a music genre and musical form which originated in the Deep South of the United States around the 1860s. Blues incorporated spirituals, work songs, field hollers, shouts, chants, and rhymed simple narrative ballads from the Afr ...
and the
Fender Rhodes The Rhodes piano (also known as the Fender Rhodes piano) is an electric piano invented by Harold Rhodes, which became popular in the 1970s. Like a conventional piano, the Rhodes generates sound with keys and hammers, but instead of strings, th ...
as used in rock music; with these instruments and genres, keyboardists often purposely overdrive a tube amplifier to get a natural overdrive sound. Another example of instrument amplification where as little distortion as possible is sought is with acoustic instrument amplifiers, designed for musicians playing instruments such as the
mandolin A mandolin ( it, mandolino ; literally "small mandola") is a stringed musical instrument in the lute family and is generally plucked with a pick. It most commonly has four courses of doubled strings tuned in unison, thus giving a total of 8 ...
or
fiddle A fiddle is a bowed string musical instrument, most often a violin. It is a colloquial term for the violin, used by players in all genres, including classical music. Although in many cases violins and fiddles are essentially synonymous, th ...
in a folk or bluegrass style.


See also

* Distortion meter *
Guitar pedalboard A guitar pedalboard is a flat board or panel that serves as a container, patch bay, and power supply for Effects unit, effects pedals for the electric guitar. Some pedalboards contain their own transformer and power cables to power multiple peda ...
*
Tube sound Tube sound (or valve sound) is the characteristic sound associated with a vacuum tube amplifier (valve amplifier in British English), a vacuum tube-based audio amplifier. At first, the concept of ''tube sound'' did not exist, because practically ...
/Valve sound


References


External links


A Musical Distortion Primer
(R.G. Keen) Article on the physics of distortion and electronic techniques

(Jon Blackstone) Article on the physics of distortion, with interactive demonstrations
Amptone.com
An archived version of a website on overdriven guitar amplifier and effects, covering: tone settings, distortion voicing, simulation and modeling, processors, speakers, power-supply modifications, switching and signal routing gear, software and recording, and DIY projects.
AX84
Cooperative, non-profit website offering free schematics and plans for building guitar amps.
Fuzz Central
Many schematics and DIY fuzz pedal projects

Technical website with information on multiFX pedals {{DEFAULTSORT:Distortion (Music) Amplified instruments Effects units Electric guitars Audio effects