A phaser is an
electronic sound processor used to
filter
Filter, filtering or filters may refer to:
Science and technology
Computing
* Filter (higher-order function), in functional programming
* Filter (software), a computer program to process a data stream
* Filter (video), a software component tha ...
a signal, and it has a series of troughs in its frequency-attenutation graph. The position (in Hz) of the peaks and troughs are typically
modulated
In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
by an internal
low-frequency oscillator
Low-frequency oscillation (LFO) is an electronic frequency that is usually below 20 Hz and creates a rhythmic pulse or sweep. This is used to modulate musical equipment such as synthesizers to create audio effects such as vibrato, tremol ...
so that they vary over time, creating a sweeping effect.
Phasers are often used to give a "synthesized" or electronic effect to natural sounds, such as human speech. The voice of
C-3PO
C-3PO () or See-Threepio is a humanoid robot character in the '' Star Wars'' franchise who appears in the original trilogy, the prequel trilogy and the sequel trilogy. Built by Anakin Skywalker, was designed as a protocol droid intended to as ...
from ''
Star Wars
''Star Wars'' is an American epic film, epic space opera multimedia franchise created by George Lucas, which began with the Star Wars (film), eponymous 1977 film and quickly became a worldwide popular culture, pop-culture Cultural impact of S ...
'' was created by taking the actor's voice and treating it with a phaser.
Process
![Phaser spectrogram](https://upload.wikimedia.org/wikipedia/commons/9/99/Phaser_spectrogram.jpg)
The electronic phasing effect is created by splitting an audio signal into two paths. One path treats the signal with an
all-pass filter
An all-pass filter is a signal processing filter that passes all frequencies equally in gain, but changes the phase relationship among various frequencies. Most types of filter reduce the amplitude (i.e. the magnitude) of the signal applied to i ...
, which preserves the amplitude of the original signal and alters the phase. The amount of change in phase depends on the frequency. When signals from the two paths are mixed, the frequencies that are out of phase will cancel each other out, creating the phaser's characteristic notches. Changing the mix ratio changes the depth of the notches; the deepest notches occur when the mix ratio is 50%.
The definition of phaser typically excludes such devices where the all-pass section is a
delay line; such a device is called a
flanger
Flanging is an audio signal processing, audio effect produced by mixing two identical audio signal, signals together, one signal delayed by a small and (usually) gradually changing period, usually smaller than 20 milliseconds. This produces a s ...
. Using a
delay line creates an unlimited series of equally spaced notches and peaks. It is possible to cascade a delay line with another type of all-pass filter. This combines the unlimited number of notches from the flanger with the uneven spacing of the phaser.
Structure
Traditional electronic phasers use a series of variable
all-pass phase-shift networks which alter the phases of the different frequency components in the signal. These networks pass all frequencies at equal volume, introducing only phase change to the signal. Human ears are not very responsive to phase differences, but this creates audible
interference
Interference is the act of interfering, invading, or poaching. Interference may also refer to:
Communications
* Interference (communication), anything which alters, modifies, or disrupts a message
* Adjacent-channel interference, caused by extr ...
s when mixed back with the dry (unprocessed) signal, creating notches. The simplified structure of a mono phaser is shown below:
![Phaser](https://upload.wikimedia.org/wikipedia/commons/7/79/Phaser.svg)
The number of
all-pass filter
An all-pass filter is a signal processing filter that passes all frequencies equally in gain, but changes the phase relationship among various frequencies. Most types of filter reduce the amplitude (i.e. the magnitude) of the signal applied to i ...
s (usually called ''stages'') varies with different models, some analog phasers offer 4, 6, 8 or 12 stages. Digital phasers may offer up to 32 or even more. This determines the number of notches/peaks in the sound, affecting the general sound character. A phaser with n stages generally has n/2 notches in the spectrum, so a 4-stage phaser will have two notches.
Additionally, the output can be fed back to the input for a more intense effect, creating a resonant effect by emphasizing frequencies between notches. This involves feeding the output of the all-pass filter chain back to the input, as shown here:
![Phaser response with feedback](https://upload.wikimedia.org/wikipedia/commons/8/84/Phaser_response_with_feedback.png)
The frequency response of an 8-stage phaser with or without feedback is shown. Note that the peaks between the notches are sharper when there's feedback, giving a distinct sound.
A
stereo
Stereophonic sound, or more commonly stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configuration ...
phaser is usually two identical phasers modulated by a
quadrature signal; the output of the oscillators for the left and right channels are a quarter-wave
out of phase
In physics and mathematics, the phase of a periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is denoted \phi(t) and expressed in such a scale that it ...
.
Most modern phasers are a part of a
digital signal processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...
, often emulating analog phasers. Phasers are mostly found as
plugins for sound editing software, as a part of a monolithic
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 ...
sound effect unit, or as "
stompbox" guitar effects.
Usage
The term was often used to refer to the original tape
flanging
Flanging is an audio effect produced by mixing two identical signals together, one signal delayed by a small and (usually) gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and not ...
effect heard on many
psychedelic
Psychedelics are a subclass of hallucinogenic drugs whose primary effect is to trigger non-ordinary states of consciousness (known as psychedelic experiences or "trips").Pollan, Michael (2018). ''How to Change Your Mind: What the New Science of ...
records of the late 1960s, notably "
Itchycoo Park
"Itchycoo Park" is a song written by Steve Marriott and Ronnie Lane, first recorded by their group, the Small Faces. Largely written by Lane, it was one of the first music recordings to feature flanging, an effect at that time made possible ...
" (1967) by the
Small Faces
Small Faces were an English rock band from London, founded in 1965. The group originally consisted of Steve Marriott, Ronnie Lane, Kenney Jones and Jimmy Winston, with Ian McLagan replacing Winston as the band's keyboardist in 1966. The ...
. The
Eventide
Eventide, an archaic word for evening, may also refer to:
* ''Eventide'' (EP), a 1998 EP by Monique Brumby
* ''Eventide'' (''Magic: The Gathering''), a 2008 trading card expansion set
* '' Eventide: A Scene in the Westminster Union'', an 1878 pa ...
Instant Phaser from 1971 was one of the first studio devices to emulate the tape flanging effect (with all-pass filters instead of delay, thus being one of the first to distinguish phasing from flanging). It was widely employed in the studio and in live settings by artists such as
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
Todd Rundgren
Todd Harry Rundgren (born June 22, 1948) is an American multi-instrumentalist, singer, songwriter, multimedia artist, sound engineer and record producer who has performed a diverse range of styles as a solo artist and as a member of the band Ut ...
. Phasing is a popular effect for
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 ...
. In 1968, Shin-ei's
Uni-Vibe
The Uni-Vibe, also marketed as the Jax Vibra-Chorus,Harry Shapiro, Michael Heatley, Roger Mayer''Jimi Hendrix Gear'', page 120 Voyageur Press is a footpedal-operated phaser or phase shifter for creating chorus and vibrato simulations for elec ...
effects pedal, designed by audio engineer Fumio Mieda, incorporated
phase shift
In physics and mathematics, the phase of a periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is denoted \phi(t) and expressed in such a scale that it v ...
, soon becoming favorite effects of guitarists such as
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 ...
and
Robin Trower
Robin Leonard Trower (born 9 March 1945) is an English rock guitarist who achieved success with Procol Harum throughout 1967–1971, and then again as the bandleader of his own power trio known as the Robin Trower Band.
Biography
Robin Trowe ...
.
By the early 1970s, phasing was available as a portable guitar effect, the first being the Maestro Phase Shifter PS-1 designed by
Tom Oberheim
Thomas Elroy Oberheim (born July 7, 1936, Manhattan, Kansas), known as Tom Oberheim, is an American audio engineer and electronics engineer best known for designing effects processors, analog synthesizers, sequencers, and drum machines. He has ...
. Unlike other phase shifters to follow, the Maestro PS-1 had three buttons to control the speed: slow, medium, and fast speed. Notable users of the Maestro Phase Shifter were
John Paul Jones
John Paul Jones (born John Paul; July 6, 1747 July 18, 1792) was a Scottish-American naval captain who was the United States' first well-known naval commander in the American Revolutionary War. He made many friends among U.S political elites ( ...
of
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 ...
,
Alex Lifeson
Aleksandar Živojinović, (born 27 August 1953), known professionally as Alex Lifeson (), is a Canadian musician, best known as the guitarist and backing vocalist of the progressive rock band Rush. In 1968, Lifeson co-founded the band that wo ...
of
Rush, and
Ernie Isley
Ernest Isley (born March 7, 1952) is an American musician, best known as a member of the musical ensemble The Isley Brothers, and also the splinter group Isley-Jasper-Isley.
Biography
Ernie was born in Cincinnati, where his older brothers for ...
of
The Isley Brothers
The Isley Brothers ( ) are an American musical group originally from Cincinnati, Ohio, that began as a vocal trio consisting of brothers O'Kelly Isley Jr., Rudolph Isley and Ronald Isley in the 1950s. With a career spanning over seven decades, ...
. Another notable early example was the
MXR Phase 90
The MXR Phase 90 is a phaser effects pedal introduced in 1972 by MXR.
History
The Phase 90 was the first pedal sold by MXR and helped launch the company in 1974. The original model had a simple orange enclosure with a script style MXR logo. In ...
which featured a control knob for speed control. From 1974,
Steve Hackett
Stephen Richard Hackett (born 12 February 1950) is an English musician, singer, songwriter and record producer who gained prominence as the lead guitarist of the progressive rock band Genesis from 1971 to 1977. Hackett contributed to six Genesis ...
of Genesis, in the ''
Selling England by the Pound
''Selling England by the Pound'' is the fifth studio album by the English progressive rock band Genesis, released in September 1973 on Charisma Records. It reached in the United Kingdom and in the United States. A single from the album, " I ...
'' (1973) studio album and tour, used the MXR Phase 90 for his Les Pauls, and from ''
The Lamb Lies Down On Broadway
''The Lamb Lies Down on Broadway'' is the sixth studio album by the English progressive rock band Genesis. It was released as a double album on 18 November 1974 by Charisma Records and is their last to feature original frontman Peter Gabriel. It ...
'' (1974) album and tour, used the ''phase filter'' section in his
Electronic Music Studios
Electronic Music Studios (EMS) is a synthesizer company formed in Putney, London in 1969 by Peter Zinovieff, Tristram Cary and David Cockerell. It is now based in Ladock, Cornwall.
Founders
The founding partners had wide experience in both elect ...
Synthi Hi-Fli. In the late 1970s,
Brian May
Brian Harold May (born 19 July 1947) is an English guitarist, singer, songwriter, and astrophysicist, who achieved worldwide fame as the lead guitarist of the rock band Queen (band), Queen. May was a co-founder of Queen with lead singer Fredd ...
used large amounts of phasing, in such songs as "
Sheer Heart Attack
''Sheer Heart Attack'' is the third studio album by the British rock band Queen, released on 8 November 1974 by EMI Records in the United Kingdom and by Elektra Records in the United States. Digressing from the progressive themes featured on t ...
". In the late 1970s and 1980s,
Eddie Van Halen
Edward Lodewijk Van Halen ( , ; January 26, 1955 – October 6, 2020) was an American musician and songwriter. He was the guitarist, keyboardist, backing vocalist, and primary songwriter of the rock band Van Halen, which he co-founded along ...
often used the MXR Phase 90 as part of his signal chain, for example in the instrumental "
Eruption
Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...
" and on the song "Atomic Punk".
Keyboard players also used phasing: in the 1970s,
keyboard instrument
A keyboard instrument is a musical instrument played using a keyboard, a row of levers which are pressed by the fingers. The most common of these are the piano, organ, and various electronic keyboards, including synthesizers and digital piano ...
s like 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 ...
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 ...
, the
Eminent 310
The Eminent 310 Unique is a home electronic organ that was built and introduced in 1972 by the Dutch organ manufacturer Eminent, at the time based in Bodegraven, the Netherlands. It was the first organ to include a string section, making it the ...
electronic organ
An electric organ, also known as electronic organ, is an electronic keyboard instrument which was derived from the harmonium, pipe organ and theatre organ. Originally designed to imitate their sound, or orchestral sounds, it has since developed ...
, and the
Clavinet
The Clavinet is an electrically amplified clavichord invented by Ernst Zacharias and manufactured by the Hohner company of Trossingen, West Germany, from 1964 to 1982. The instrument produces sounds by a rubber pad striking a point on a tension ...
were commonly treated with a phaser, especially in
avant-garde jazz
Avant-garde jazz (also known as avant-jazz and experimental jazz) is a style of music and improvisation that combines avant-garde art music and composition with jazz. It originated in the early 1950s and developed through to the late 1960s. Orig ...
.
Bill Evans
William John Evans (August 16, 1929 – September 15, 1980) was an American jazz pianist and composer who worked primarily as the leader of his trio. His use of impressionist harmony, interpretation of traditional jazz repertoire, block ch ...
, for instance, used a Maestro phaser on ''
Intuition
Intuition is the ability to acquire knowledge without recourse to conscious reasoning. Different fields use the word "intuition" in very different ways, including but not limited to: direct access to unconscious knowledge; unconscious cognition; ...
'' (1974).
The phaser is also used to "sweeten" their sounds. Examples can be heard in
Billy Joel
William Martin Joel (born May 9, 1949) is an American singer, pianist and songwriter. Commonly nicknamed the "Piano Man (song), Piano Man" after his album and signature song of the same name, he has led a commercially successful career as a solo ...
's "Just The Way You Are",
Styx's "Babe", and
Jean Michel Jarre
Jean-Michel André Jarre (; born 24 August 1948) is a French composer, performer and record producer. He is a pioneer in the electronic, ambient and new-age genres, and is known for organising outdoor spectacles featuring his music, accompanie ...
's ''
Oxygène
''Oxygène'' (, en, Oxygen) is the third studio album by French electronic musician and composer Jean-Michel Jarre. It was first released in France in December 1976 by Disques Motors, and distributed internationally in 1977 by Polydor Records. J ...
'' (1976) on which he used an EHX Small Stone phaser extensively.
Tony Banks (
Genesis
Genesis may refer to:
Bible
* Book of Genesis, the first book of the biblical scriptures of both Judaism and Christianity, describing the creation of the Earth and of mankind
* Genesis creation narrative, the first several chapters of the Book of ...
) used an
MXR Phase 100 on his RMI 368x Electra piano from 1974 (later he inserted this effect, as well as the fuzzbox, into the Electra's panel); from late 1977 he also used the phaser (along with a
Boss
Boss may refer to:
Occupations
* Supervisor, often referred to as boss
* Air boss, more formally, air officer, the person in charge of aircraft operations on an aircraft carrier
* Crime boss, the head of a criminal organization
* Fire boss, a ...
CE-1) on his Hammond organ to replace the
Leslie's rotating effect.
Daft Punk
Daft Punk were a French electronic music duo formed in 1993 in Paris by Thomas Bangalter and Guy-Manuel de Homem-Christo. Widely regarded as one of the most influential acts in dance music history, they achieved popularity in the late 1990s as p ...
helped to re-popularize the effect in the 21st century, utilizing it on a number of tracks on their
''Discovery'' album in 2001.
Richard Tee
Richard Edward Tee (born Richard Edward Ten Ryk; November 24, 1943 – July 21, 1993) was an American pianist, studio musician, singer and arranger, who had several hundred studio credits and played on such notable hits as "In Your Eyes", " Sl ...
also used a phase shifter hooked up to his
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 ...
.
In
motion picture
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...
or
television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
production, the effect created by a phaser is often used to imply that the sound is synthetically generated, like turning a natural human voice into a computer or robot voice. The technique works because the frequency filtering produces sound commonly associated with mechanical sources, which only generate specific frequencies, rather than natural sources, which produce a range of frequencies.
Vocoder
A vocoder (, a portmanteau of ''voice'' and ''encoder'') is a category of speech coding that analyzes and synthesizes the human voice signal for audio data compression, multiplexing, voice encryption or voice transformation.
The vocoder was ...
and
ring modulation
In electronics, ring modulation is a signal processing function, an implementation of frequency mixing, in which two signals are combined to yield an output signal. One signal, called the carrier, is typically a sine wave or another simple w ...
are also used to create synthetic effects.
Similar effects
A specific type of phasing,
flanging
Flanging is an audio effect produced by mixing two identical signals together, one signal delayed by a small and (usually) gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and not ...
is a similar effect, in which the notches are linearly spaced. In a flanger effect, the notches are created by mixing the signal with a
delay
Delay (from Latin: dilatio) may refer to:
Arts, entertainment, and media
* ''Delay 1968'', a 1981 album by German experimental rock band Can
* ''The Delay'', a 2012 Uruguayan film
People
* B. H. DeLay (1891–1923), American aviator and acto ...
ed version of itself. Flangers tend to sound more pronounced and natural, like the "jet plane whoosh" effect, whereas phasers tend to sound more subtle and otherworldly. For comparison of the two effects, check .
The
Uni-Vibe
The Uni-Vibe, also marketed as the Jax Vibra-Chorus,Harry Shapiro, Michael Heatley, Roger Mayer''Jimi Hendrix Gear'', page 120 Voyageur Press is a footpedal-operated phaser or phase shifter for creating chorus and vibrato simulations for elec ...
is an early phase-shifting effect that uses
photoresistor
A photoresistor (also known as a photocell, or light-dependent resistor, LDR, or photo-conductive cell) is a passive component that decreases resistance with respect to receiving luminosity (light) on the component's sensitive surface. The elect ...
s for modulation.
See also
*
Chorus effect
Chorus (or chorusing, choruser or chorused effect) is an audio effect that occurs when individual sounds with approximately the same time, and very similar pitches, converge. While similar sounds coming from multiple sources can occur naturally, ...
*
Shepard tone
A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the ''Shepard scale''. This cre ...
*
Wave interference
In physics, interference is a phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive ...
Notes
References
External links
The technology of phase shifters and flangersHow does a phaser work? video by Empress Effects
{{DEFAULTSORT:Phaser (Effect)
Audio effects