Editing Effects unit (section)

==Techniques{{anchor|Types}}==
{{broader|Sound effect#Techniques}}
[[File:Jim O'Rourke-6.jpg|thumb|[[Jim O'Rourke (musician)|Jim O’Rourke]] kneeling while operating two stompboxes with his hands]]

===Distortion===
{{main|Distortion (music)}}
{{Listen|filename=DistortionPedalDemo.ogg|title=Distortion effect|description=Electric guitar played first ''clean'' (no effects), then with distortion pedal.|format=[[Ogg]]}}
[[File:Clipping waveform.svg|thumb|right|[[Clipping (audio)|Clipping]] an instrument's [[audio signal]] produces distortion]]

Distortion, overdrive, and fuzz effects units add a ''warm'', ''gritty'', or ''fuzzy'' character to an audio signal by re-shaping or [[clipping (audio)|clipping]] it, which [[distorts]] the shape of its [[waveform]] by flattening its peaks, creating ''warm'' sounds by adding [[harmonics]] or ''gritty'' sounds by adding [[inharmonic]] overtones. Distortion effects are sometimes called [[Gain (electronics)|gain]] effects, as distorted guitar sounds were first achieved by increasing the gain of [[tube amplifier]]s.<ref>{{Cite book|last=Menasche|first=Emile D.|title=Home Studio Clinic: A Musician's Guide to Professional Recording|publisher=Hal Leonard|year=2007|page=[https://archive.org/details/homestudioclinic0000mena/page/80 80]|isbn=9781423418078 |url=https://archive.org/details/homestudioclinic0000mena|url-access=registration}}</ref><ref name="Ross">{{Cite book|last=Ross|first=Michael|url=https://books.google.com/books?id=CddgbKkAoxYC&pg=PA39|title=Getting Great Guitar Sounds|publisher=Hal Leonard|year=1998|page=39|isbn=9780793591404}}</ref><ref name="google171">Aikin, Jim (2004). [https://books.google.com/books?id=_042p3GHkBQC ''Power Tools for Synthesizer Programming''], Hal Leonard. p. 171.</ref>

While distortion effects units produce perfectly flattened peaks or ''hard'' clipping, overdrive effects units produce ''soft'' tube-like distortion by compressing the waveform without completely flattening it. Much like guitar tube amplifiers, overdrive effects units are capable of producing ''clean'' sounds at lower volumes and distorted ''warm'' sounds at higher volumes.<ref>{{Cite book|last1=Zölzer|last2=Amatriain|first1=Udo|first2=Xavier|url=https://books.google.com/books?id=h90HIV0uwVsC|title=DAFX: Digital Audio Effects|publisher=John Wiley and Sons|year=2002|page=117|isbn=9780471490784}}</ref><ref>{{Citation|last=Brewster|first=David M.|title=Introduction to Guitar Tone and Effects: A Manual for Getting the Sounds from Electric Guitars, Amplifiers, Effects Pedals and Processors|publisher=Hal Leonard|url=https://books.google.com/books?id=q99-bY3cL8YC&q=overdrive+tube+amplifier&pg=PA18|year=2001|page=18|isbn=9780634060465}}</ref>

Notable [[List of distortion pedals|examples of distortion and overdrive pedals]] include the [[Boss DS-1]] Distortion, [[Ibanez Tube Screamer]], [[Marshall ShredMaster]], [[MXR Distortion +]], and [[Pro Co RAT]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

A fuzz pedal, or fuzzbox, is a type of overdrive effects unit that clips a signal until it is nearly a [[Square wave (waveform)|square wave]], resulting in a heavily distorted or ''fuzzy'' sound.<ref name="google171"/><ref>Platt, Charles (2009). [https://books.google.com/books?id=PQzYdC3BtQkC ''MAKE: Electronics: Learning Through Discovery''] O'Reilly Media. p. 257.</ref> Fuzzboxes may contain [[frequency multiplier]] circuitry to achieve a harsh [[timbre]] by adding complex [[harmonics]].<ref>{{Cite book|last1=Holmes|first1=Thom|title=The Routledge Guide to Music Technology|publisher=CRC Press|year=2006|page=177|url=https://books.google.com/books?id=iH1tZ64riu4C&q=%22frequency+multiplier%22&pg=PA117|isbn=0-415-97324-4}}</ref><ref>{{Cite book|last1=Manning|first1=Peter|title=Electronic and Computer Music|publisher=Oxford University Press US|year=2004|page=170|url=https://books.google.com/books?id=P2dClS4LdPQC&pg=PA170|isbn=0-19-514484-8}}</ref> [[The Rolling Stones]]' song "[[(I Can't Get No) Satisfaction]]", with a fuzz effect featured prominently on the main electric guitar riff played by Keith Richards, greatly popularized the use of fuzz effects.<ref name="museumofmakingmusic1">{{cite web|title=The Art of the Stompbox|publisher=The Museum of Making|year=2010|url=http://www.museumofmakingmusic.org/stompbox-effects|access-date=13 September 2010}}</ref> [[Fuzz bass]] (also called bass overdrive) is a style of playing the [[electric bass]] that produces a buzzy, overdriven sound via a tube or transistor amp or by using a fuzz or overdrive pedal.

Notable examples of fuzz effect units include the: [[Fuzz Face|Arbiter Fuzz Face]], [[Electro-Harmonix Big Muff]], [[Shin-ei Companion FY-2]], [[Univox Super-Fuzz]], [[Tone Bender|Vox Tone Bender]], [[Z.Vex Fuzz Factory]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians. Wikipedia is NOT a free advertising service-->

While distortion effect units are most associated with electric and bass guitar, they are also commonly used on keyboard instruments (i.e. [[synthesizer]]s, [[Combo organ|combo]] and [[tonewheel organ]]s, [[electric piano]]), as well as drums and vocals.

===Dynamics===
[[File:Comp. rack (Supernatural).jpg|thumb|upright|A rack of [[rackmount]] audio compressors in a recording studio. From top to bottom: Retro Instruments/Gates STA level; Spectra Sonic; [[Dbx (noise reduction)|Dbx]] 162; Dbx 165; [[Empirical Labs Distressor]]; Smart Research C2; Chandler Limited TG1; Daking FET (91579); and [[Altec Lansing|Altec]] 436c.]]

Also called volume and [[amplitude]] effects, dynamics effects modify the volume of an instrument. Dynamics effects were among the first effects introduced to guitarists.<ref name="art" />

''Boost/volume pedal'': When activated, a ''boost'' or ''clean boost'' pedal amplifies the volume of an instrument by increasing the [[amplitude]] of its [[audio signal]]. These units are generally used for ''boosting'' volume during solos and preventing signal loss in long effects chains. A guitarist switching from rhythm guitar to lead guitar for a [[guitar solo]] may use a boost to increase the volume of their solo.<ref>Hunter, Dave (2004). [https://books.google.com/books?id=7DjYrk7Vap4C ''Guitar Effects Pedals: The Practical Handbook'']. Hal Leonard. p. 23.</ref>

Volume effects: [[Electro-Harmonix]] LPB-1, Fender Volume Pedal, [[MXR Micro Amp]], [[Ernie Ball Inc.|Ernie Ball]] Volume Pedal.<!--This article has often been used to advertise. Add only list products that 1.) have Wikipedia articles and 2. ) have been very known for a number of years and used by influential musicians--> [[Treadle]]-based volume pedals are used by electric instrument players (guitar, bass, keyboards) to adjust the volume of their instrument with one foot while their hands are being used to play their instrument. Treadle-style volume pedals are often also used to create swelling effects by removing the attack of a note or chord, as popularised by [[pedal steel guitar]] players. This enables electric guitar and pedal steel players to imitate the soft swelling sound that an orchestra [[string section]] can produce, in which a note or chord starts very softly and then grows in volume. Treadle-based volume pedals do not usually have batteries or require external power.

''[[Dynamic range compression|Compressor]]'': Compressors make loud sounds quieter and quiet sounds louder by decreasing or ''compressing'' the [[dynamic range compression|dynamic range]] of an [[audio signal]].<ref name="Reese">{{Cite book|last1=Reese|first1=David|last2=Gross|first2=Lynne|last3=Gross|first3=Brian|title=Audio Production Worktext: Concepts, Techniques, and Equipment|publisher=Focal Press|year=2009|page=[https://archive.org/details/audioproductionw0000rees/page/149 149]|url=https://archive.org/details/audioproductionw0000rees|url-access=registration|isbn=978-0-240-81098-0}}</ref> A compressor is often used to stabilize volume and alter the sound of a note's ''attack''. With extreme settings of its controls, a compressor can function as a [[limiter]].<ref name="google23">Hunter, D (2004). [https://books.google.com/books?id=7DjYrk7Vap4C ''Guitar Effects Pedals: The Practical Handbook'']. Hal Leonard. p. 23.</ref>

Compressor effects: [[Robert Keeley (instrument maker)|Keeley Compressor]], [[MXR Dyna Comp]], [[Boss Corporation|Boss CS-3 Compression Sustainer]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2.) have been well known for a number of years and used by influential musicians-->

''[[Noise gate]]'': Noise gates [[attenuate]] hum, hiss, and static in the signal by greatly diminishing the volume when the signal falls below a set threshold. Noise gates are [[Dynamic range compression#Types|expanders]]—meaning that, unlike compressors, they increase the [[dynamic range compression|dynamic range]] of an [[audio signal]] to make quiet sounds even quieter.<ref name="Reese" /> If used with extreme settings and combined with reverb, they can create unusual sounds, such as the [[gated reverb|gated drum effect]] used in 1980s pop songs, a style popularized by the [[Phil Collins]] song ''[[In the Air Tonight]]''.<ref>Louie, Gary J.; White, Glenn D. (2005). [https://books.google.com/books?id=DulVm8t88QkC ''The Audio Dictionary''], University of Washington Press. p. 171.</ref><ref>{{cite magazine |last=Flans |first=Robyn |url=http://mixonline.com/mag/audio_phil_collins_air/ |title=Classic Tracks: Phil Collins' "In the Air Tonight" |archive-url=https://web.archive.org/web/20110303210034/http://mixonline.com/mag/audio_phil_collins_air/ |archive-date=3 March 2011 |magazine=Mix |date=1 May 2005}}</ref>

Noise gate effects: [[Boss Corporation|Boss NS-2 Noise Suppressor]].

===Filter===
Filter effects alter the [[frequency]] content of an [[audio signal]] that passes through them by either boosting or weakening specific frequencies or frequency regions.

''[[Equalization (audio)|Equalizer]]'': An equalizer is a set of [[linear filter]]s that strengthen (''boost'') or weaken (''cut'') specific [[frequency]] regions. While basic [[Hifi|home stereos]] often have equalizers for two bands, to adjust bass and treble, professional [[graphic equalizer]]s offer much more targeted control over the audio frequency spectrum.<ref>Rudolph, Thomas; Leonard, Vincent (2001) [https://books.google.com/books?id=MFSilO_OEPAC ''Recording in the Digital World: Complete Guide to Studio Gear and Software''], Hal Leonard . p. 192.</ref> [[Audio engineers]] use highly sophisticated equalizers to eliminate unwanted sounds, make an instrument or voice more prominent, and enhance particular aspects of an instrument's tone.<ref>{{Cite book|last=Strong|first=Jeff|title=PC Recording Studios for Dummies|url=https://books.google.com/books?id=4-2SfnghnYwC&q=pc+recording+studios+for+dummies|publisher=For Dummies|year=2005|page=25|isbn=9780764577079}}</ref>

Equalizer effects: [[Boss Corporation|Boss GE-7 Equalizer]], [[MXR]] 10-band EQ Pedal.

[[File:Peter Frampton's Talk Box-3-2.jpg|thumb|left|[[Peter Frampton]]'s [[Talk box]]]]
''[[Talk box]]'': A talk box directs the sound from an electric guitar or synthesizer into the mouth of a performer using a tube, allowing the sound to be shaped into [[vowel]]s and [[consonant]]s with movements of the mouth. The modified sound is then picked up by a microphone. In this way, the guitarist is able create the effect that the guitar is talking. Some famous uses of the talkbox include [[Bon Jovi]]'s "[[Livin' on a Prayer]]", [[Songs in the Key of Life|Stevie Wonder]]'s "[[Black Man (song)|Black Man]]", [[Mötley Crüe]]'s "[[Kickstart My Heart]]", [[Joe Walsh]]'s "[[Rocky Mountain Way]]", [[Alice in Chains]]'s "[[Man in the box]]" and [[Peter Frampton]]'s "[[Show Me the Way (Peter Frampton song)|Show Me the Way]]".<ref>{{cite web|last=Dyers|first=Jon|url=http://www.dyers.org/blog/archives/2008/03/21/the-talkbox-will-never-die-a-talkbox-playlist/|title=The Talkbox Will Never Die: A Talkbox Playlist|publisher=Dyers|date=21 March 2008|access-date=20 September 2010|archive-url=https://web.archive.org/web/20100617102921/http://www.dyers.org/blog/archives/2008/03/21/the-talkbox-will-never-die-a-talkbox-playlist/|archive-date=17 June 2010|url-status=dead}}</ref><ref>{{cite web|url=http://www.blamepro.com/talkbox.htm#top|title=The Talkbox FAQ|author=McCarron, Brett|access-date=10 September 2010}}</ref>

Talk boxes: [[Dunlop Manufacturing|Dunlop HT1 Heil Talk Box]], [[Bruce Egnater|Rocktron Banshee]].<!--This article has often been used to advertise. Please list only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

[[File:Thomas Organ Crybaby.jpg|thumb|right|Thomas Organ Cry Baby [[Wah-wah pedal]] (1970) manufactured by JEN]]
''[[Wah-wah pedal|Wah-wah]]'': A wah-wah pedal creates vowel-like sounds by altering the [[Audio spectrum|frequency spectrum]] produced by an instrument—i.e., how loud it is at each separate [[frequency]]—in what is known as a [[spectral glide]] or ''sweep''.<ref>{{Cite book|last1=Denton|first1=Dailey J.|title=Electronics for Guitarists|publisher=Springer|year=2011|page=183|isbn=9781441995360|url=https://books.google.com/books?id=PPg5_lPQJyMC&pg=PA185}}</ref> The device is operated by a foot treadle that manipulates a [[potentiometer]] or other electronic control. Wah-wah pedals are often used by [[funk]] and rock guitarists.<ref name="The Contemporary Guitar">Schneider, John (1985). [https://books.google.com/books?id=6-QE1jyJHgEC ''The Contemporary Guitar''], University of California Press. p. 202.</ref>

Wah effects: [[Dunlop Cry Baby]],<ref>{{Cite web |url=https://www.sweetwater.com/feature/dunlop/wah-pedals/ |title=Wah Comparison Chart | access-date= 17 August 2020 }}</ref> [[Morley Pedals|Morley Power Wah]], [[Vox (company)|Vox]].<ref>[https://voxamps.com/series/wah-pedal/ Vox V846 Wah]</ref><!--This article has often been used to advertise. Please list only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

''[[Auto-wah]]'' or, more generally, envelope filter effects: A filter effect that is controlled by the volume of the input signal.<ref name="The Boss Book">''The Boss Book: The Ultimate Guide to the World's Most Popular Compact Effects for Guitar'', 2002, Hal Leonard Corporation</ref>  The most common filter type used for this effect pedal is the low-pass filter, although many designs include a toggle for band-pass or high-pass filters as well.  Additionally, some designs can switch between a down filter mode and an up filter.  This effect is commonly used in funk, reggae and jam band music.

Envelope filter effects: [[Mu-tron|Musitronics Mu-Tron III]], Electro-Harmonix Q-Tron Plus,<ref>[https://www.ehx.com/products/q-tron-plus/ Electro-Harmonix Q-Tron Plus]</ref> DOD Envelope Filter 440.<ref>[https://www.digitech.com/discontinued-products/Envelope+Filter+440.html DOD Envelope Filter 440] {{Webarchive|url=https://web.archive.org/web/20210629054118/https://www.digitech.com/discontinued-products/Envelope+Filter+440.html |date=29 June 2021 }}</ref>

===Modulation===
{{listen
|filename =Demo chorus.ogg
|title  =Chorus effect
|description=Chorus effect on guitar, coming from an Electro-Harmonix Small Clone
|filename2=Flanging effect.ogg
|title2  =Flanging effect
|description2=A short synthesizer sample followed by two flanging versions
|filename3=Phasing_effect.ogg
|title3  =Phaser effect
|description3=Unprocessed organ followed by different phasing effects
|filename4=Ring_Modulation-with_2500Hz.ogg
|title4  =Ring modulation effect
|description4=Bell-like sound
|filename5=LFOtoVolume-Tremolo.ogg
|title5  =Tremolo effect
|description5=A low-frequency oscillator modulating a tremolo (synthesizer)
|filename6=LFOtoPitch-Vibrato.ogg
|title6  =Vibrato effect
|description6=A low-frequency oscillator modulating a vibrato (synthesizer)
}}
[[Modulation]], in general electronics, means the altering of one signal based on another. In audio effects, modulation is a control feature that varies the strength or other attribute of the effect over time to alter tonal properties. Some modulation effects modulate an instrument's [[audio signal]] with a signal generated by the effect called a [[carrier wave]].<ref name="Zolzer">{{Cite book|last1=Zölzer|last2=Amatriain|first1=Udo|first2=Xavier|url=https://books.google.com/books?id=h90HIV0uwVsC|title=DAFX: Digital Audio Effects|publisher=John Wiley and Sons|year=2002|page=76|isbn=9780471490784}}</ref> Other modulation effects split an instrument's audio signal in two, altering one portion of the signal and mixing it with the unaltered portion.<ref name="Coulter">{{cite book |last=Coulter |first=Doug |date=2000 |title=Digital Audio Processing |publisher=Taylor & Francis |page=271 |isbn=9780879305666}}<!--imperfectly recovered reference: previous indicated |url=https://books.google.com/books?id=_VIKe7n9R_8C (not found) |publisher=Focal Press |date=2001 possibly a different edition, page number may be incorrect--></ref>

''[[chorus effect|Chorus]]'': Chorus pedals mimic the effect [[choir]]s and [[string orchestra]]s produce naturally, by mixing similar sounds with slight differences in [[timbre]] and [[pitch (music)|pitch]]. A chorus effect splits the [[audio signal]] and adds a slight delay and [[frequency]] variations or ''[[vibrato]]'' to one version while leaving the rest unaltered.<ref name="Coulter" /><ref>{{Cite book|last=Perkins|first=Chad|title=The After Effects Illusionist: All the Effects in One Complete Guide|publisher=Focal Press|year=2009|page=37|url=https://books.google.com/books?id=qsvgDeyrz-0C&q=chorus+signal+delay&pg=PA37|isbn=978-0-240-81145-1}}</ref> A well-known usage of chorus is the lead guitar in "[[Come as You Are (Nirvana song)|Come As You Are]]" by [[Nirvana (band)|Nirvana]].<ref name="google23"/>

Chorus effects: [[Boss Corporation|Boss]] CE-1 Chorus Ensemble, [[Electro-Harmonix]] Small Clone, [[TC Electronic]] Stereo Chorus.<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

''[[Flanger]]'': A flanger creates a ''whooshing'', ''jet plane'' or ''spaceship'' sound, simulating a studio effect that was first produced by recording a track on two synchronized [[Reel-to-reel audio tape recording|tape decks]] and periodically slowing one tape by pressing the edge of its reel (the ''flange''). When the two tapes' [[audio signal]]s are later mixed, a [[comb filter]] effect can be heard. Flanger units add a variably delayed version of the audio signal to the original or signal, creating a comb filter or [[Doppler effect]].<ref>{{Cite book|last=Kurasaki|first=Kurt|title=Power Tools for Reason 3.0: Master the World's Most Popular Virtual Studio|publisher=Hal Leonard|year=2005|page=169|isbn=9780879308612|url=https://books.google.com/books?id=nPkBCZ1F7kAC&pg=PA169}}</ref><ref>Louie, G; White, G (2005). [https://books.google.com/books?id=DulVm8t88QkC ''The Audio Dictionary''], University of Washington Press. p. 153.</ref> Some famous uses of flanger effects include "[[Walking on the Moon]]" by [[The Police]], the intro to "[[Ain't Talkin' 'Bout Love]]" by [[Van Halen]], and "[[Barracuda (song)|Barracuda]]" by [[Heart (band)|Heart]].<ref>{{cite web|url=http://www.igdb.co.uk/pages/reviews/effect/electro_harmonix/deluxe_electric_mistress.htm|title=Electro Harmonix Deluxe Electric Mistress Review|publisher=Internet Guitar Database|access-date=19 September 2001|archive-url=https://web.archive.org/web/20051030020829/http://www.igdb.co.uk/pages/reviews/effect/electro_harmonix/deluxe_electric_mistress.htm|archive-date=30 October 2005|url-status=dead}}</ref><ref>{{Citation|last=Brewster|first=David M.|title=Introduction to Guitar Tone and Effects: A Manual for Getting the Sounds from Electric Guitars, Amplifiers, Effects Pedals and Processors|publisher=Hal Leonard|url=https://books.google.com/books?id=q99-bY3cL8YC|year=2001|page=29|isbn=9780634060465}}</ref>

Flanger effects: [[Electro-Harmonix]] Electric Mistress, [[MXR]] Flanger, [[Boss Corporation|Boss]] BF-3 Flanger.<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

[[File:MXR M-101 Phase 90 modified.jpg|thumb|left|200px|An MXR-101 Phaser pedal]]
''[[Phaser (effect)|Phaser]]'': A phaser or phase shifter creates a slight rippling effect—amplifying some aspects of the tone while diminishing others—by splitting an [[audio signal]] in two and altering the [[Phase (waves)|phase]] of one portion. Three well-known examples of phaser are the [[two-handed tapping]] part on the Van Halen instrumental "[[Eruption (instrumental)|Eruption]]" and the keyboard parts on [[Billy Joel]]'s "[[Just the Way You Are (Billy Joel song)|Just the Way You Are]]" and [[Paul Simon]]'s "[[Slip Slidin' Away]]".<ref>Louie, G; White, G. (2005). [https://books.google.com/books?id=DulVm8t88QkC ''The Audio Dictionary''], University of Washington Press. p. 288.</ref>

Phase shift effects: [[Uni-Vibe]], [[Electro-Harmonix]] Small Stone, [[MXR Phase 90]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

''[[Ring modulator]]'': A ring modulator produces a resonant, metallic sound by [[frequency mixing]] an instrument's [[audio signal]] with a [[carrier wave]] generated by the device's internal [[Electronic oscillator|oscillator]]. The original sound wave is suppressed and replaced by a ''ring'' of [[inharmonic]] higher and lower [[pitch (music)|pitches]] or [[sideband]]s.<ref name="Zolzer" /><ref>{{Citation|last=Moog|first=Robert|author-link=Robert Moog|title=Synthesizer technique|publisher=Hal Leonard|series=Keyboard Synthesizer Library|volume=2|year=1984|chapter=Pitch Blending, Modulation, and Expression|page=52|chapter-url=https://books.google.com/books?id=IQrOFoWL0T4C&pg=PA53|isbn=0-88188-290-9}}</ref> A notable use of [[ring modulation]] is the guitar in the [[Black Sabbath]] song "[[Paranoid (Black Sabbath song)|Paranoid]]".<ref>McNamee, David [https://www.theguardian.com/music/2009/nov/09/ring-modulators "Hey, What's That Sound: Ring Modulators"], ''The Guardian'', London, 9 November 2009.</ref>

Ring modulator effects: [[Moogerfooger#MF-102|Moogerfooger MF-102 Ring Modulator]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

''[[Tremolo]]'': A tremolo effect produces a variation in the volume of a signal. The tremolo effect should not be confused with the misleadingly-named [[tremolo bar]], a device on a guitar bridge that creates a [[vibrato]] or [[pitch-bending]] effect. In electronic effects, a tremolo is produced by modulating an instrument's audio signal with a [[Subaudible tone|sub-audible]] carrier wave in such a way that generates amplitude variations in the sound wave.<ref>{{Citation|last=Hartman|first=W. M.|date=19 March 1979|title=The Electronic Music Synthesizer and the Physics of Music|publisher=American Association of Physics Teachers|url=http://www.pa.msu.edu/acoustics/ajpsynth.pdf|access-date=2021-10-10|archive-date=5 March 2016|archive-url=https://web.archive.org/web/20160305034409/http://www.pa.msu.edu/acoustics/ajpsynth.pdf|url-status=dead}}</ref><ref name="Holmes">{{Citation|last=Holmes|first=Thomas|title=Electronic and Experimental Music: Technology, Music, and Culture|url=https://books.google.com/books?id=hCthQ-bec-QC&q=vibrato+%22carrier+wave%22+%22carrier+signal%22&pg=PA198|year=2008|publisher=Taylor & Francis|isbn=978-0-415-95781-6|page=198}}</ref> Tremolo effects are built-in effects in some vintage [[guitar amplifiers]]. The guitar intro in the [[Rolling Stones]]' "[[Gimme Shelter]]" features a tremolo effect.<ref>{{cite web|url=http://www.guitaretab.com/r/rolling-stones/16342.html|title=Rolling Stones – Gimme Shelter tab|author=Trolet, Jean-Pierre|access-date=9 September 2010}}</ref>

Tremolo effects: Demeter TRM-1 Tremulator, [[Fender Tremolux]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

''[[Slicer (guitar effect)|Slicer]]'': Combines a [[modulation]] sequence with a [[noise gate]] or [[envelope filter]] to create a percussive and rhythmic effect like a helicopter.<ref>{{cite web |url=https://rolandcorp.com.au/blog/guitar-fx-101-guide-guitar-effects-pedals#FXS |title=Guitar FX-101: Your Guide to Guitar Effects Pedals |date=6 August 2016 |publisher=[[Roland Corporation]] |access-date=2020-03-14}}</ref>

''[[Vibrato]]'': Vibrato effects produce slight, rapid variations in [[Pitch (music)|pitch]], mimicking the fractional [[semitone]] variations produced naturally by [[opera singer]]s and violinists when they are prolonging a single note. Vibrato effects often allow the performer to control the rate of the variation as well as the difference in pitch (''depth''). A vibrato with an extreme ''depth'' setting (e.g., half a semitone or more) will produce a dramatic, [[ululating]] sound. In [[transistor]]ized effects, vibrato is produced by mixing an instrument's [[audio signal]] with a [[carrier wave]] in such a way that generates frequency variations in the sound wave.<ref name="Holmes" /> Guitarists often use the terms ''[[vibrato]]'' and ''[[tremolo]]'' misleadingly. A so-called ''vibrato unit'' in a guitar amplifier may actually produces tremolo, while a ''[[tremolo arm]]'' or ''whammy bar'' on a guitar produces vibrato.<ref>Mangum, E; Stubbs, D (2000). [https://books.google.com/books?id=pp6xpWAgjFcC ''Dod Presents 100 Superstar Guitar Sounds on a Stompbox Budget'']. Hal Leonard. p. 94.</ref><ref>Fischer, Peter (2000), [https://books.google.com/books?id=fFSEYzW5SAAC ''Rock Guitar Secrets''], Mel Bay. p. 164.</ref>

Vibrato effects: [[Boss Corporation|Boss VB-2 Vibrato]].

===Pitch and frequency===
{{Main article|Pitch shifter}}
[[File:EH POG-2.jpg|thumb|right|An [[Electro-Harmonix]] Polyphonic Octaver Generator (POG)]]

A pitch shifter (also called an ''octaver'' for effects that shift pitch by an [[octave]]) raises or lowers (i.e. [[Transposition (music)|transposes]]) each note a performer plays by a pre-set [[Interval (music)|interval]]. For example, a pitch shifter set to increase the pitch by a fourth will raise each note four [[diatonic]] intervals above the notes actually played. Simple, less expensive pitch shifters raise or lower the pitch by one or two [[octave]]s, while more sophisticated devices offer a range of interval alterations. A pitch shifter can be used by an electric guitarist to play notes that would normally only be available on an electric bass. As well, a bass player with a four string electric bass can use an octave pedal to obtain low notes that would normally only be obtainable with a five-string bass with a low B string.

A harmonizer is a type of sophisticated pitch shifter that combines the altered pitch with the original pitch to create a two or three note [[harmony]] based on the original pitch. Some hamonizers are able to create chorus-like effects by modulating of small shifts in pitch.<ref>Izhaki, Roey (2007). [https://books.google.com/books?id=tIi4HQ2kWRoC ''Mixing Audio: Concepts, Practices and Tools''], Focal Press. p. 470.</ref>

The first mass-market digital pitch shifter was the [[DigiTech Whammy]], introduced in 1989.<ref name="Lynham-20192">{{Cite web |last=Lynham |first=Alex |date=2019-08-02 |title=The FX files: DigiTech Whammy |url=https://www.musicradar.com/news/the-fx-files-digitech-whammy |access-date=2024-07-27 |website=[[MusicRadar]] |language=en}}</ref> It creates a "strange and artificial" sound, with distinctive "wobbly" [[Artifact (error)|artifacts]].<ref name=":0">{{Cite web |last=Greeves |first=David |date=April 2013 |title=Digitech Whammy (5th Gen) |url=https://www.soundonsound.com/reviews/digitech-whammy-5th-gen |access-date=2021-09-16 |website=[[Sound on Sound]]}}</ref><ref name="Lynham-20193">{{Cite web |last=Lynham |first=Alex |date=2019-08-02 |title=The FX files: DigiTech Whammy |url=https://www.musicradar.com/news/the-fx-files-digitech-whammy |access-date=2024-07-27 |website=[[MusicRadar]] |language=en}}</ref> Its users include [[Jonny Greenwood]] and [[Ed O'Brien]] of [[Radiohead]],<ref>{{Cite journal |date=19 October 2018 |title=Iron man |url=https://www.pressreader.com/australia/total-guitar/20181019/283016875682882 |journal=[[Total Guitar]] |publisher=[[Future plc]] |via=[[PressReader]]}}</ref><ref>{{cite web |author=Astley-Brown |first1=Michael |last2=Laing |first2=Rob |date=14 November 2017 |title=Radiohead's Ed O'Brien: 'I was always drawn to sounds that didn't sound like the guitar' |url=http://www.musicradar.com/news/radioheads-ed-obrien-i-was-always-drawn-to-sounds-that-didnt-sound-like-the-guitar |access-date=19 November 2017 |website=[[MusicRadar]] |publisher=}}</ref> [[Matt Bellamy]] of [[Muse (band)|Muse]],<ref name="Charupakorn-2022">{{Cite web |last=Charupakorn |first=Joe |date=11 August 2022 |title=Muse's Matt Bellamy: Natural-Born Disruptor |url=https://www.premierguitar.com/artists/guitarists/muse |website=[[Premier Guitar]]}}</ref> [[Tom Morello]] of [[Rage Against the Machine]] and [[Audioslave]],<ref name="Lynham-20193" /> [[David Gilmour]] of [[Pink Floyd]]<ref>{{Cite web |last=Tolinski |first=Brad |date=September 1994 |title=David Gilmour discusses guitars, blues and ''The Division Bell'' in 1994 ''Guitar World'' interview |url=https://www.guitarworld.com/gw-archive/david-gilmour-discusses-guitars-blues-and-division-bell-1994-guitar-world-interview |access-date=2024-07-27 |website=[[Guitar World]] |language=en}}</ref> and [[Jack White]] of the [[White Stripes]].<ref>{{Cite web |last=Gill |first=Chris |date=2020-07-09 |title=The secrets behind Jack White's guitar tone on the White Stripes' Seven Nation Army |url=https://www.guitarworld.com/features/the-secrets-behind-jack-whites-guitar-tone-on-the-white-stripes-seven-nation-army |access-date=2024-07-27 |website=[[Guitar World]] |language=en}}</ref> ''[[Guitar World]]'' described the Whammy as one of the most iconic guitar pedals.<ref name="Vallese-20122">{{Cite web |last=Vallese |first=Nick |date=2012-06-05 |title=Digitech releases new Whammy with chord shifting |url=https://www.guitarworld.com/uncategorized/digitech-releases-new-whammy-chord-shifting |access-date=2021-09-16 |website=[[Guitar World]] |language=en}}</ref><!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

===Time-based===
[[File:Maestro Echoplex EP-2.jpg|right|thumb|A vintage [[Echoplex]] EP-2 delay effect]]
{{listen
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|title=Delay effect
|description=A flute before and after delay|format=[[Ogg]]
|filename2=Reverberation_effect.ogg
|title2=Reverberation effect
|description2=Reverb with increasingly longer delay
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Time-based effects delay the sound signal, add reverb or echos, or enable musicians to record and play back [[Loop (music)|loops]].

''[[Delay (audio effect)|Delay/echo]]'': Delay/echo units produce an echo effect by adding a duplicate to the original signal at a slight time delay. The effect can either be a single echo (called a ''slap'' or ''slapback''), or multiple echos. A well-known use of delay is the lead guitar in the [[U2]] song "[[Where the Streets Have No Name]]", and also the opening riff of "[[Welcome to the Jungle]]" by [[Guns N' Roses]].<ref>Hubner, David; Runstein, Robert (2009). [https://books.google.com/books?id=W9U7A-rSXtEC ''Modern Recording Techniques''], Focal Press. p. 508.</ref>

Delay effects: [[Boss Corporation|Boss]] DD-3 Digital Delay, [[MXR]] Carbon Copy, [[Electro-Harmonix]] Deluxe Memory Man, [[Line 6 DL4]], [[Roland RE-201]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians--><!--[[User:Kvng/RTH]]-->

''Looper pedal'': A looper pedal or "phrase looper" allows a performer to record and later replay a phrase, [[riff]] or passage from a song. Loops can be created on the spot during a performance ([[live looping]]) or they can be pre-recorded. By using a looper pedal, a singer-guitarist in a [[one person band]] can play the backing chords (or riffs) to a song, loop them with the pedal, and then sing and do a [[guitar solo]] over the chords. Some units allow a performer to layer multiple loops, enabling the performer to create the effect of a full band.<ref>{{cite web|title = Starting Point|url = http://loopermusic.com/starting-point|website = LooperMusic.com|access-date = 28 December 2015}}</ref> The first loop effects were created with [[reel-to-reel tape]] using a [[tape loop]]. High-end boutique tape loop effects are still used by some studio producers who want a vintage sound. Digital loop effects recreate this effect using an electronic memory.<ref>{{Cite book|last=Hopper|first=Jessica|title=The Girl's Guide to Rocking Out|url=https://books.google.com/books?id=RwzQe_h-OjQC|year=2009|publisher=Workman Publishing|page=34|isbn=9780761151418}}</ref><!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians-->

[[File:Reverb-4-2.jpg|thumb|left|Folded line spring reverberation]]
''[[Reverb effect|Reverb]]'': Reverb units simulate the spacious sounds produced naturally in a huge stone cathedral (or other [[acoustic space]] such as a hall or room). This is done by creating a large number of echoes that gradually fade away in volume or "decay". One early technique for creating a reverb effect was to send an amplified signal of the music via a speaker to another room with reflective surfaces, such as a tile bathroom, and then record the natural reverberations that were produced. A plate reverb system uses an electromechanical [[transducer]] to create vibrations in a plate of metal. [[Spring reverb]] systems, which are often used in guitar amplifiers, use a transducer to create vibrations in a spring. Digital reverb effects use various [[Digital signal processing|signal processing]] [[algorithm]]s to create the reverb effect, often by using multiple feedback [[Delay (audio effect)|delay circuits]]. [[Rockabilly]] and [[surf guitar]] are two genres that make heavy use of reverb.<ref>Hubner, D; Runstein, R (2009). [https://books.google.com/books?id=W9U7A-rSXtEC ''Modern Recording Techniques''], Focal Press. p. 508.</ref>

Reverb effects: [[Electro-Harmonix]] Holy Grail, [[Fender Reverb Unit]].<!--This article has often been used to advertise. List only products that 1.) have Wikipedia articles and 2. ) have been well known for a number of years and used by influential musicians and which have WP articles-->

===Feedback/sustain===

''[[Audio feedback]]'': Audio feedback is an effect produced when amplified sound is picked up by a microphone or guitar pickup and played back through a [[guitar amplifier]], initiating a "feedback loop", which usually consists of high-pitched sound. Feedback that occurs from a vocal mic into a [[PA system]] is almost always avoided. However, in some styles of rock music, electric guitar players intentionally create feedback by playing their instrument directly in front of a heavily amplified, [[distortion (music)|distorted]] [[guitar amplifier]]'s [[speaker enclosure]]. The creative use of feedback effects was pioneered by guitarists such as [[Jimi Hendrix]] in the 1960s. This technique creates sustained, high-pitched [[overtone]]s and unusual sounds not possible through regular playing techniques. Guitar feedback effects can be difficult to perform, because it is difficult to determine the sound volume and guitar position relative to a guitar amp's loudspeaker necessary for achieving the desired feedback sound.<ref>Wright, Ed (2007). [https://books.google.com/books?id=ysmj8vITtzcC ''Left-Handed History of the World''], Murdoch Books. p. 209.</ref><ref>Amelar, Chris (1997). [https://books.google.com/books?id=KsV_l0FeKlwC ''The Guitar F/X Cookbook''], Hal Leonard. p. 41.</ref> Guitar feedback effects are used in a number of rock genres, including [[psychedelic rock]], [[heavy metal music]] and [[punk rock]].
[[File:EBow.jpg|thumb|left|upright|An [[EBow]] guitar string resonator]]

[[EBow]] is a [[brand name]] of Heet Sound Products, of Los Angeles, California, for a small, handheld, battery-powered resonator. The Ebow was invented by Greg Heet, as a way to make a note on an electric guitar string resonate continuously, creating an effect that sounds similar to a bowed violin note or a sustained [[pipe organ]] note. The resonator uses a [[Pickup (music technology)|pickup]] – inductive string driver – feedback circuit, including a sensor coil, driver coil, and amplifier, to induce forced string resonance. The Ebow brand resonator is monophonic, and drives only one string at a time.

Other handheld and mounted guitar and bass resonators have been on the market since the early 1990s, produced in Germany under the SRG brand, which ceased production in 2016, and were available in both monophonic (one string at a time) and polyphonic (multiple strings at a time) models, which included multiple onboard trigger switch effects, such as HPF (high pass filter) for enhancing harmonics and producing feedback effects, and LPF (low pass filter), producing a bass boost with a cello sound on heavy gauge strings.<ref>{{Cite web |url=http://www.effectsdatabase.com/model/srg/d1 |title=Archived copy |access-date=4 May 2020 |archive-date=20 January 2022 |archive-url=https://web.archive.org/web/20220120202528/https://www.effectsdatabase.com/model/srg/d1 |url-status=dead }}</ref> Later EBow models, such as the plus Ebow, contain a mode slide switch on the back, which allows the player to either produce just sustain or [[overtone]] feedback in addition to sustain.<ref name="The Contemporary Guitar"/> Pedals such as the Boss DF-2 and FB-2 use an internally generated signal matched to the pitch of the guitar that can be sustained indefinitely by depressing the pedal. Many [[#Dynamics|compressor pedals]] are often also marketed as "sustainer pedals". As a note is sustained, it loses energy and volume due to diminishing vibration in the string. The compressor pedal boosts its electrical signal to the specified [[dynamic range]], slightly prolonging the duration of the note.<ref>Hunter, Dave (2004). [https://books.google.com/books?id=7DjYrk7Vap4C ''Guitar Effects Pedals: The Practical Handbook'']. Hal Leonard. p. 25.</ref> This, combined with heavy distortion and the close proximity of the guitar and the speaker cabinet, can lead to infinite sustain at higher volumes.

===Other effects===
''Envelope follower'': An envelope follower activates an effect once a designated volume is reached. One effect that uses an envelope follower is the ''[[auto-wah]]'', which produces a "wah" effect depending on how loud or soft the notes are being played.<ref>{{Cite book|last=White, G|first=Louie, G|title=The Audio Dictionary Instruments|url=https://books.google.com/books?id=DulVm8t88QkC&q=flanger+jet+plane|year=2005|publisher=University of Washington Press|page=138|isbn=9780295984988}}</ref><ref>{{Cite book|last=Hopper|first=J|title=The Girl's Guide to Rocking Out|url=https://books.google.com/books?id=RwzQe_h-OjQC|year=2009|publisher=Workman Publishing|page=33|isbn=9780761151418}}</ref>
[[File:Line 6 Flextone III Plus control panel.jpg|thumb|right|A Line 6 modeling amplifier shown from above. Note the various amplifier and speaker emulations selectable via the rotary knob on the left.]]
''[[Guitar amplifier]] modeling'': [[Amplifier modeling]] is a [[Digital data|digital]] effect that replicates the sound of various amplifiers, most often vintage [[tube amplifier]]s and famous brands of speaker cabinets (e.g., the [[Ampeg SVT]] 8x10" bass cabinet). Sophisticated modeling effects can simulate different types of [[speaker cabinet]]s (e.g., the sound of an 8x10" cabinet) and [[miking]] techniques. A rotary speaker simulator mimics the [[doppler]] and [[chorus effect]] sound of a vintage [[Leslie speaker]] system by replicating its volume and pitch modulations, [[overdrive (music)|overdrive]] capacity and [[phase shift]]s.<ref>Bartlett, B; Bartlett, J (2008). [https://books.google.com/books?id=E0uy8adetQoC ''Practical Recording Techniques: The Step-by-step Approach to Professional Audio Recording'']. Focal Press. p. 226.</ref>

''[[Pitch correction]]/vocal effects'': Pitch correction effects use signal-processing algorithms to re-tune faulty intonation in a vocalist's performance <ref>Brice, Richard (2001). [https://books.google.com/books?id=ufVVgLwkcQwC ''Music Engineering''], Newnes. p. 413.</ref> or create unusual [[vocoder]]-type vocal effects. One of the best known examples of this is [[Autotune]], a software program and effect unit which can be used to both correct pitch (it moves a pitch to the nearest semitone), and add vocal effects. Some stompbox-style vocal pedals contain multiple effects, such as reverb and pitch correction.

''Simulators'': Simulators enable electric guitars to mimic the sound of other instruments such as [[Steel-string guitar|acoustic guitar]], electric bass and [[sitar]]. [[Pick up (music technology)|Pick up]] simulators used on guitars with [[single-coil]] pick ups replicate the sound of guitars with [[humbucker]] pick ups, or vice versa. A de-[[fret]]ter is a bass guitar effect that simulates the sound of a [[fretless bass]]. The effect uses an [[Voltage-controlled filter|envelope-controlled filter]] and [[voltage-controlled amplifier]] to "soften" a note's attack both in volume and [[timbre]].<ref>{{cite web|url=http://www.kellyindustries.com/guitars/boss_gt8.html|title=Boss GT-8 Floor Guitar Effects Processor|access-date=10 September 2010|archive-url=https://web.archive.org/web/20100207042056/http://www.kellyindustries.com/guitars/boss_gt8.html|archive-date=7 February 2010|url-status=dead}}</ref>

''[[Bitcrusher]] filters'': Bitcrushers rely on conversion of the audio signal into a digital format (ADC) and the reduction of sound fidelity by utilising bit (and sometimes sample) rates low enough to cause significant colouration and filtering within the audible frequency range.

[[File:Leslie Speaker.jpg|thumb|right|200px|A Leslie rotary speaker in a clear plastic cabinet. Typically, the Leslie is housed in a wooden cabinet.]]
''[[Leslie speaker|Rotary speakers]]'' are specially constructed [[amplifier]] and [[loudspeaker]]s used to create special audio effects by rotating the speakers or a sound-directing duct
to introduce the [[Doppler effect]] and other sound reflections. The rotating speaker baffle creates a chorus-type effect. Named after its inventor, [[Donald Leslie]], it is particularly associated with the [[Hammond organ]] but is used with a variety of instruments as well as vocals. The Hammond/Leslie combination has become an element in many genres of music. The Leslie Speaker and the Hammond Organ brands are currently owned by [[Suzuki Musical Instrument Corporation]].

The ''[[Korg Kaoss Pad]]'' is a small [[touchpad]] [[MIDI]] controller, [[sampler (musical instrument)|sampler]], and effects processor for audio and musical instruments, made by [[Korg]]. The Kaoss Pad's touchpad can be used to control its internal effects engine, which can be applied to a line-in signal or to samples recorded from the line-in. Effects types include pitch shifting, [[distortion]], filtering, [[wah-wah (music)|wah-wah]], [[tremolo]], [[flanging]], [[delay (audio effect)|delay]], [[reverberation]], auto-panning, gating, [[phasing]], and [[ring modulation]].
The Kaoss Pad can also be used as a [[MIDI controller]].