Editing Effects unit (section)

===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-->