Automatic double tracking
Encyclopedia
Automatic double-tracking or artificial double-tracking (ADT) was an analogue recording
technique designed to enhance the sound of voices or instruments during the recording process. It used tape delay
to create a delayed copy of an audio signal which was then combined with the original. The effect was intended to simulate the sound of the natural doubling of voices or instruments achieved by double tracking. The technique was originally developed in 1966 by engineers at Abbey Road Studios
in London
at the request of The Beatles
.
for use in sound recording. Originally, a pair of single-track (or "mono") tape recorders were used to produce the effect; later, multitrack
tape machines were used. Early exponents of this technique were Les Paul
and Buddy Holly
. Before the development of ADT, it was necessary to either record the vocal track twice on two different tracks of a multitrack tape, or to record the vocal first on one tape, then again on a second tape while simultaneously copying the first to the second—a process that could be both tedious and exacting, and might require several takes. After the development of ADT, this process became known as "manual double tracking".
's Abbey Road Studios, mainly at the instigation of John Lennon
. Lennon hated the tedium of double tracking during sessions and regularly expressed a desire for a technical alternative.
Townsend realised that, if two identical performances were played back with one of them slightly out of sync, the sound image would alter and widen, similarly to double tracking. There was no reliable way that this effect could be achieved by simply copying a vocal track on to another deck and then playing it back with the master slightly out of sync; at the time, there was no technique for synchronising two different tape machines. The end result would be that the second tape deck would gradually drift further and further from the first.
album, and on many of their subsequent recordings. It has been incorrectly claimed that the first use of ADT was on the first half of Lennon’s vocal track on "Tomorrow Never Knows
", but in fact this vocal track features manual double tracking. However most of the doubletracked vocals heard on the rest of the album were created using ADT, while the group also used the technique on a number of the instrumental parts to colour the sounds – there is in fact more use of ADT on the mono version of the album than on the more widely known stereo
version, with the lead guitar on "Taxman" and the backwards guitar on "I'm Only Sleeping
" treated with the effect. ADT could not only be used to create a single double-tracked sound image; but when used on a stereo mix, the effect could be used to "split" the vocal between the two stereo channels, creating the impression of two different vocal parts on either side of the stereo picture. This technique was used on the stereo mixes of "I'm Only Sleeping", "Love You To
", "And Your Bird Can Sing
", and "Doctor Robert
" (on "Here, There and Everywhere
", the similar effect heard is actually two different vocals manually double-tracked and panned; on "Eleanor Rigby
", the effect is obtained by a combination of manual double-tracking and ADT). This technique could also be applied to instrumental parts as well: on "Love You To", the same use of ADT was applied to the acoustic guitar track, giving the impression of multiple guitars panned left and right.
jokingly told him it was produced using a "double-bifurcated sploshing flange". Only years later did Martin learn that another technique, also called flanging
, was already in use (it is rumoured that recording engineer Joe Meek
was the inventor of flanging in the 1950s; however, it is more often attributed to Townsend. Whether that attribution is valid or not is contested because of the close contact between George Martin, who misnomered ADT as flanging, and Townsend.) The term referred to an engineer's alternately pressing and releasing his finger against the flange (rim) of the supply reel on one of two synchronized tape machines as the same audio signal was combined and transferred to a third machine, slightly slowing the machine then allowing it to come back up to speed and in sync with the other, applying a "swooshing" comb filter
ing effect to the combined audio signal. Alternatively, the engineer could press the flange of one supply reel then the other to achieve a fuller effect.
An additional explanation for the pedigree of flanging has it named after Fred Flange, a pseudonym given to Matt Monro
by Peter Sellers, who used a Monro recording to open his 1959 Sinatra parody album Songs for Swingin' Sellers. The album was produced by Martin, and presumably the connection with flanging comes from Monro's mimicking (double-tracking) Sinatra. Engineers at Abbey Road realised that the technique they had developed needed a proper technical name and eventually christened it ADT, short for "Artificial Double Tracking", although elsewhere the term "Automatic Double Tracking" became more common.
The Beatles used ADT widely in conjunction with manual double-tracking on all their subsequent albums, with the exception of Let It Be, which was initially intended to be an "honest" album utilising no technical artifice (ADT can still be heard on the finished album, however, because Phil Spector
treated a Hammond organ
part with it on his mix of the title track). Some notable examples of ADT use by the Beatles in the years following Revolver include "Fixing a Hole
" (where the bass guitar part is treated with ADT in an attempt to simulate a "fretless tone"), "Within You, Without You" (on which ADT is supposedly used on almost every vocal and instrumental part on the track), "I Am the Walrus
" (which uses ADT in conjunction with equalisation to help simulate a "fake stereo" effect on the second half of the stereo mix, which was sourced from the mono mix, by splitting the entire mix between the channels), and the unusually wide ADT used on the lead vocal tracks on "Being for the Benefit of Mr. Kite" and "Blue Jay Way
".
's debut album The Piper at the Gates of Dawn
, recorded at Abbey Road in 1967. As well as using it for more conventional simulated double tracking, Smith made much use of the technique to split Syd Barrett
's vocals between the stereo channels. In some cases, Smith (or possibly Barrett himself) used such extraordinarily wide ADT in this way as to give the slightly disorientating impression of not so much double tracking but two quite separate voices on either channel wildly out of time with each other – the best example of this is perhaps on "Bike
". Similar effects were later used on some of Barrett's solo works, perhaps indicating his fondness for this unusual use of ADT. Pink Floyd themselves continued to use ADT on most, if not all, of their subsequent albums up until the 1980s, with one notable use being on "Alan's Psychedelic Breakfast
", where a part of the drum track is treated with ADT.
In the US, Simon and Garfunkel
began to use ADT on stereo mixes of their songs to split vocal tracks between the channels, examples of which include "Mrs. Robinson
" and "Cecilia
".
Gary Kellgren
, Jimi Hendrix
's engineer, made extensive use of ADT on all of Jimi's albums, frequently using the technique to split vocal, guitar, and even drum parts between the stereo channels.
" rather than "flanging"). The Beatles themselves used this effect on "Lucy in the Sky with Diamonds
" and more prominently on "Blue Jay Way". A notable example of this technique is "Itchycoo Park
" by the Small Faces, where the effect is prominent almost throughout the entire track, particularly on the vocals, drums and cymbals during the chorus. Hendrix also utilised this technique extensively. An example of an ADT variation being used to create an effect more similar to what is considered "flanging" today (rather than phasing) is on the Beatles' White Album tracks "Cry Baby Cry
" and "While My Guitar Gently Weeps
" – the former features "flanging" on the acoustic guitar part, the latter on the lead guitar.
, flangers, and phasers
, all of which use an oscillating delay (or, in the phaser, a variable phase network).
technology in the 1980s (although not all engineers could apparently figure out how to reproduce the effect successfully, with Jack Douglas
recalling that he was at a loss when John Lennon asked him to use ADT on his vocals during a recording session in 1980 but was unable to adequately explain to his producer how the tape decks should be set up to create the effect). With the advent of digital recording, tape- and analog-based delay methods have not been much used, though many of these analog techniques are frequently emulated using comparable digital techniques, or in some cases plugins which are used to extend the capabilities of a Digital audio workstation
. Although using digital delay to simulate double-tracking produces a very similar effect to ADT, some claim to be able to hear the difference between the two (certainly one can tell the difference between digital delay and manual double-tracking, as was the case with ADT in previous years – manual double-tracking continues to be used by a number of artists). Some musicians and engineers may casually use the term ADT to refer to any form of simulated double tracking, including digital delay used in this manner, although strictly speaking the term should refer to the analogue technique. One of the very few examples of ADT being used in recent times is on the Beatles' Anthology
albums from the mid-1990s, on which George Martin and Geoff Emerick
decided to revive the analogue technique rather than simply use the modern digital alternatives in order to achieve a more authentic sound, feeling that ADT produced a warmer, less synthetic sound than digital delay and the latter would be inappropriate for use on recordings made on analogue equipment in the 1960s.
Magnetic tape sound recording
The use of magnetic tape for sound recording originated around 1930. Magnetizable tape revolutionized both the radio broadcast and music recording industries. It did this by giving artists and producers the power to record and re-record audio with minimal loss in quality as well as edit and...
technique designed to enhance the sound of voices or instruments during the recording process. It used tape delay
Delay (audio effect)
Delay is an audio effect which records an input signal to an audio storage medium, and then plays it back after a period of time. The delayed signal may either be played back multiple times, or played back into the recording again, to create the sound of a repeating, decaying echo.-Early delay...
to create a delayed copy of an audio signal which was then combined with the original. The effect was intended to simulate the sound of the natural doubling of voices or instruments achieved by double tracking. The technique was originally developed in 1966 by engineers at Abbey Road Studios
Abbey Road Studios
Abbey Road Studios is a recording studio located at 3 Abbey Road, St John's Wood, City of Westminster, London, England. It was established in November 1931 by the Gramophone Company, a predecessor of British music company EMI, its present owner...
in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
at the request of The Beatles
The Beatles
The Beatles were an English rock band, active throughout the 1960s and one of the most commercially successful and critically acclaimed acts in the history of popular music. Formed in Liverpool, by 1962 the group consisted of John Lennon , Paul McCartney , George Harrison and Ringo Starr...
.
Overview
As early as the 1950s, it was discovered that double tracking the lead vocal in a song gave it a fuller, more appealing sound, especially for singers with weak or light voices. Use of this technique became possible with the advent of magnetic tapeMagnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
for use in sound recording. Originally, a pair of single-track (or "mono") tape recorders were used to produce the effect; later, multitrack
Multitrack recording
Multitrack recording is a method of sound recording that allows for the separate recording of multiple sound sources to create a cohesive whole...
tape machines were used. Early exponents of this technique were Les Paul
Les Paul
Lester William Polsfuss —known as Les Paul—was an American jazz and country guitarist, songwriter and inventor. He was a pioneer in the development of the solid-body electric guitar which made the sound of rock and roll possible. He is credited with many recording innovations...
and Buddy Holly
Buddy Holly
Charles Hardin Holley , known professionally as Buddy Holly, was an American singer-songwriter and a pioneer of rock and roll...
. Before the development of ADT, it was necessary to either record the vocal track twice on two different tracks of a multitrack tape, or to record the vocal first on one tape, then again on a second tape while simultaneously copying the first to the second—a process that could be both tedious and exacting, and might require several takes. After the development of ADT, this process became known as "manual double tracking".
Ken Townsend
ADT was invented especially for the Beatles during the spring of 1966 by Ken Townsend, a recording engineer employed at EMIEMI
The EMI Group, also known as EMI Music or simply EMI, is a multinational music company headquartered in London, United Kingdom. It is the fourth-largest business group and family of record labels in the recording industry and one of the "big four" record companies. EMI Group also has a major...
's Abbey Road Studios, mainly at the instigation of John Lennon
John Lennon
John Winston Lennon, MBE was an English musician and singer-songwriter who rose to worldwide fame as one of the founding members of The Beatles, one of the most commercially successful and critically acclaimed acts in the history of popular music...
. Lennon hated the tedium of double tracking during sessions and regularly expressed a desire for a technical alternative.
The double tracking effect
Because it is impossible for a performer to sing or play the same part in exactly the same way twice, a recording and blending of two different performances of the same part will create a fuller, "chorused" effect with double tracking. But if one simply plays back two copies of the same performance in perfect sync, the two sound images become one and no double tracking effect is produced.Townsend realised that, if two identical performances were played back with one of them slightly out of sync, the sound image would alter and widen, similarly to double tracking. There was no reliable way that this effect could be achieved by simply copying a vocal track on to another deck and then playing it back with the master slightly out of sync; at the time, there was no technique for synchronising two different tape machines. The end result would be that the second tape deck would gradually drift further and further from the first.
Tape delay system
Instead, Townsend came up with a system using tape delay, after similar principles already in place for echoes applied via tape during a song mixdown. In essence, Townsend's system added a second tape recorder to the regular setup. When mixing a song, its vocal track was routed from the recording head of the multitrack tape, which was before the playback head, and fed to the record head of the second tape recorder. An oscillator was used to vary the speed of the second machine, providing more or less delay depending on how fast or slow the second machine was run relative to the first. This signal was then routed from the playback head of the second machine to a separate fader on the mixer. This allowed the delayed vocal to be combined with the normal vocal, creating the double tracked effect.Use by The Beatles
The Beatles were thrilled by Townsend's technique and used it throughout the RevolverRevolver (album)
Revolver is the seventh studio album by the English rock group The Beatles, released on 5 August 1966 on the Parlophone label and produced by George Martin. Many of the tracks on Revolver are marked by an electric guitar-rock sound, in contrast with their previous LP, the folk rock inspired Rubber...
album, and on many of their subsequent recordings. It has been incorrectly claimed that the first use of ADT was on the first half of Lennon’s vocal track on "Tomorrow Never Knows
Tomorrow Never Knows
"Tomorrow Never Knows" is the final track of The Beatles' 1966 studio album Revolver but the first to be recorded. Credited as a Lennon–McCartney song, it was written primarily by John Lennon...
", but in fact this vocal track features manual double tracking. However most of the doubletracked vocals heard on the rest of the album were created using ADT, while the group also used the technique on a number of the instrumental parts to colour the sounds – there is in fact more use of ADT on the mono version of the album than on the more widely known stereo
STEREO
STEREO is a solar observation mission. Two nearly identical spacecraft were launched into orbits that cause them to respectively pull farther ahead of and fall gradually behind the Earth...
version, with the lead guitar on "Taxman" and the backwards guitar on "I'm Only Sleeping
I'm Only Sleeping
"I'm Only Sleeping" is a song by The Beatles from their 1966 studio album Revolver. It was released two months earlier in the United States on the album Yesterday And Today and did not feature on the original US version of Revolver...
" treated with the effect. ADT could not only be used to create a single double-tracked sound image; but when used on a stereo mix, the effect could be used to "split" the vocal between the two stereo channels, creating the impression of two different vocal parts on either side of the stereo picture. This technique was used on the stereo mixes of "I'm Only Sleeping", "Love You To
Love You To
"Love You To" is a song by The Beatles from the album Revolver. It is sung and written by George Harrison and features North Indian classical instrumentation; tabla, a pair of hand-drums, sitar and a tambura providing a drone...
", "And Your Bird Can Sing
And Your Bird Can Sing
"And Your Bird Can Sing" is a song by The Beatles, released on their 1966 album Revolver in the United Kingdom and on Yesterday...and Today in the United States. The songwriting credit is Lennon–McCartney, though the song was written primarily by John Lennon, with contributions by George Harrison...
", and "Doctor Robert
Doctor Robert
"Doctor Robert" is a song by The Beatles released on the album Revolver in the United Kingdom and on Yesterday and Today in the United States. The song was written by John Lennon and Paul McCartney. It was recorded in 7 takes on 17 April 1966 with vocals overdubbed 19 April. Lennon said that he was...
" (on "Here, There and Everywhere
Here, There and Everywhere
"Here, There and Everywhere" is a song written primarily by Paul McCartney , recorded for The Beatles 1966 album Revolver. In his biography Many Years From Now, McCartney said the song is one of his favourites. Beatles' producer George Martin has also mentioned it as one of his favourite McCartney...
", the similar effect heard is actually two different vocals manually double-tracked and panned; on "Eleanor Rigby
Eleanor Rigby
"Eleanor Rigby" is a song by The Beatles, simultaneously released on the 1966 album Revolver and on a 45 rpm single. The song was written primarily by Paul McCartney and credited to Lennon–McCartney...
", the effect is obtained by a combination of manual double-tracking and ADT). This technique could also be applied to instrumental parts as well: on "Love You To", the same use of ADT was applied to the acoustic guitar track, giving the impression of multiple guitars panned left and right.
Flanging
Lennon dubbed the technique "flanging" after producer George MartinGeorge Martin
Sir George Henry Martin CBE is an English record producer, arranger, composer and musician. He is sometimes referred to as "the Fifth Beatle"— a title that he often describes as "nonsense," but the fact remains that he served as producer on all but one of The Beatles' original albums...
jokingly told him it was produced using a "double-bifurcated sploshing flange". Only years later did Martin learn that another technique, also called flanging
Flanging
Flanging is an audio effect produced by mixing two identical signals together, with one signal delayed by a small and gradually changing period, usually smaller than 20 milliseconds. This produces a swept comb filter effect: peaks and notches are produced in the resultant frequency spectrum,...
, was already in use (it is rumoured that recording engineer Joe Meek
Joe Meek
Robert George "Joe" Meek was a pioneering English record producer and songwriter....
was the inventor of flanging in the 1950s; however, it is more often attributed to Townsend. Whether that attribution is valid or not is contested because of the close contact between George Martin, who misnomered ADT as flanging, and Townsend.) The term referred to an engineer's alternately pressing and releasing his finger against the flange (rim) of the supply reel on one of two synchronized tape machines as the same audio signal was combined and transferred to a third machine, slightly slowing the machine then allowing it to come back up to speed and in sync with the other, applying a "swooshing" comb filter
Comb filter
In signal processing, a comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. The frequency response of a comb filter consists of a series of regularly spaced spikes, giving the appearance of a comb....
ing effect to the combined audio signal. Alternatively, the engineer could press the flange of one supply reel then the other to achieve a fuller effect.
An additional explanation for the pedigree of flanging has it named after Fred Flange, a pseudonym given to Matt Monro
Matt Monro
Matt Monro was an English singer who became one of the most popular entertainers on the international music scene during the 1960s...
by Peter Sellers, who used a Monro recording to open his 1959 Sinatra parody album Songs for Swingin' Sellers. The album was produced by Martin, and presumably the connection with flanging comes from Monro's mimicking (double-tracking) Sinatra. Engineers at Abbey Road realised that the technique they had developed needed a proper technical name and eventually christened it ADT, short for "Artificial Double Tracking", although elsewhere the term "Automatic Double Tracking" became more common.
ADT versus manual double tracking
Townsend's process succeeded in simulating manual double tracking quite effectively; however, attentive listeners can often tell the difference between ADT and "real" double tracking, with the former having a synthetic quality to it and having none of the audible differences between the vocal tracks frequently present in the latter. Over the years, many artists, including the Beatles, continued to use both manual double tracking, ADT, or a combination of both in different circumstances depending on the effects they wished to achieve, with each technique thought to have certain unique qualities of its own.The Beatles used ADT widely in conjunction with manual double-tracking on all their subsequent albums, with the exception of Let It Be, which was initially intended to be an "honest" album utilising no technical artifice (ADT can still be heard on the finished album, however, because Phil Spector
Phil Spector
Phillip Harvey "Phil" Spector is an American record producer and songwriter, later known for his conviction in the murder of actress Lana Clarkson....
treated a Hammond organ
Hammond organ
The Hammond organ is an electric organ invented by Laurens Hammond in 1934 and manufactured by the Hammond Organ Company. While the Hammond organ was originally sold to churches as a lower-cost alternative to the wind-driven pipe organ, in the 1960s and 1970s it became a standard keyboard...
part with it on his mix of the title track). Some notable examples of ADT use by the Beatles in the years following Revolver include "Fixing a Hole
Fixing a Hole
"Fixing a Hole" is a song written by Paul McCartney and recorded by The Beatles, featured on their 1967 album Sgt...
" (where the bass guitar part is treated with ADT in an attempt to simulate a "fretless tone"), "Within You, Without You" (on which ADT is supposedly used on almost every vocal and instrumental part on the track), "I Am the Walrus
I Am the Walrus
"I Am the Walrus" is a 1967 song by The Beatles, written by John Lennon and credited to Lennon–McCartney. Lennon claimed he wrote the first two lines on separate acid trips. The song was in the Beatles' 1967 television film and album Magical Mystery Tour, and was the B-side to the #1 hit "Hello,...
" (which uses ADT in conjunction with equalisation to help simulate a "fake stereo" effect on the second half of the stereo mix, which was sourced from the mono mix, by splitting the entire mix between the channels), and the unusually wide ADT used on the lead vocal tracks on "Being for the Benefit of Mr. Kite" and "Blue Jay Way
Blue Jay Way
"Blue Jay Way" is a song written by George Harrison; it was first recorded and released by The Beatles on their Magical Mystery Tour album and EP in 1967.-Origins:...
".
Other users of ADT
Townsend's technique, and minor variations on it, quickly caught on and almost immediately began to be used by other artists and record producers. Former Beatles engineer Norman Smith used ADT extensively on Pink FloydPink Floyd
Pink Floyd were an English rock band that achieved worldwide success with their progressive and psychedelic rock music. Their work is marked by the use of philosophical lyrics, sonic experimentation, innovative album art, and elaborate live shows. Pink Floyd are one of the most commercially...
's debut album The Piper at the Gates of Dawn
The Piper at the Gates of Dawn
The Piper at the Gates of Dawn is the debut album by the English rock group Pink Floyd, and the only one made under founding member Syd Barrett's leadership. The album contains whimsical lyrics about space, scarecrows, gnomes, bicycles and fairy tales, along with psychedelic instrumental songs...
, recorded at Abbey Road in 1967. As well as using it for more conventional simulated double tracking, Smith made much use of the technique to split Syd Barrett
Syd Barrett
Syd Barrett , born Roger Keith Barrett, was an English singer-songwriter, guitarist, and painter, best remembered as a founding member of the band Pink Floyd. He was the lead vocalist, guitarist and primary songwriter during the band's psychedelic years, providing major musical and stylistic...
's vocals between the stereo channels. In some cases, Smith (or possibly Barrett himself) used such extraordinarily wide ADT in this way as to give the slightly disorientating impression of not so much double tracking but two quite separate voices on either channel wildly out of time with each other – the best example of this is perhaps on "Bike
Bike (song)
"Bike" is a song by British psychedelic rock band Pink Floyd, and is featured on their debut album, The Piper at the Gates of Dawn .-Information:...
". Similar effects were later used on some of Barrett's solo works, perhaps indicating his fondness for this unusual use of ADT. Pink Floyd themselves continued to use ADT on most, if not all, of their subsequent albums up until the 1980s, with one notable use being on "Alan's Psychedelic Breakfast
Alan's Psychedelic Breakfast
"Alan's Psychedelic Breakfast" is a three-part instrumental track from the 1970 Pink Floyd album Atom Heart Mother.-Overview:The track features Pink Floyd playing in the background as Alan Stiles speaks about the breakfast he is preparing and eating, as well as breakfasts he has had in the past...
", where a part of the drum track is treated with ADT.
In the US, Simon and Garfunkel
Simon and Garfunkel
Simon & Garfunkel are an American duo consisting of singer-songwriter Paul Simon and singer Art Garfunkel. They formed the group Tom & Jerry in 1957 and had their first success with the minor hit "Hey, Schoolgirl". As Simon & Garfunkel, the duo rose to fame in 1965, largely on the strength of the...
began to use ADT on stereo mixes of their songs to split vocal tracks between the channels, examples of which include "Mrs. Robinson
Mrs. Robinson
"Mrs. Robinson" is a song written by Paul Simon and first performed by Simon & Garfunkel. When released as a single in 1968, it hit number one on the Billboard Hot 100 chart in the US, for their second chart-topping hit after "The Sound of Silence"...
" and "Cecilia
Cecilia (song)
"Cecilia" is a song written by US musician Paul Simon. It was first recorded by Simon and Garfunkel for their 1970 album Bridge Over Troubled Water. When released as a single, it reached #4 in the US charts...
".
Gary Kellgren
Gary Kellgren
Gary Kellgren was an American audio engineer and co-founder of The Record Plant recording studios, along with businessman Chris Stone.-Engineering:...
, Jimi Hendrix
Jimi Hendrix
James Marshall "Jimi" Hendrix was an American guitarist and singer-songwriter...
's engineer, made extensive use of ADT on all of Jimi's albums, frequently using the technique to split vocal, guitar, and even drum parts between the stereo channels.
Psychedelic music
With the rise of psychedelic music, many artists used variations on Townsend's technique to create the "flanging" effect mentioned above, adding a slightly disorientating "swooshing" quality to instruments and voices (although in practice this effect is actually more similar to what today is called "phasingPhasing
In the compositional technique phasing, the same part is played on two musical instruments, in steady but not identical tempo...
" rather than "flanging"). The Beatles themselves used this effect on "Lucy in the Sky with Diamonds
Lucy in the Sky with Diamonds
"Lucy in the Sky with Diamonds" is a song written primarily by John Lennon and credited to Lennon–McCartney, for The Beatles' 1967 album Sgt. Pepper's Lonely Hearts Club Band...
" and more prominently on "Blue Jay Way". A notable example of this technique is "Itchycoo Park
Itchycoo Park
"Itchycoo Park" is a psychedelic pop song written by Steve Marriott and Ronnie Lane, first recorded by their group, the Small Faces. The song reached number three in the UK Singles Chart, 1967.-Song profile:...
" by the Small Faces, where the effect is prominent almost throughout the entire track, particularly on the vocals, drums and cymbals during the chorus. Hendrix also utilised this technique extensively. An example of an ADT variation being used to create an effect more similar to what is considered "flanging" today (rather than phasing) is on the Beatles' White Album tracks "Cry Baby Cry
Cry Baby Cry
"Cry Baby Cry" is a song by The Beatles, written by John Lennon, from their 1968 album The Beatles.-Composition:Demos of the song indicate that Lennon wrote the song in late 1967...
" and "While My Guitar Gently Weeps
While My Guitar Gently Weeps
"While My Guitar Gently Weeps" is a song by George Harrison, first recorded by The Beatles in 1968 for their eponymous double album...
" – the former features "flanging" on the acoustic guitar part, the latter on the lead guitar.
Doubling echo
A similar technique to ADT is doubling echo, which uses short delays to mimic the double tracking effect. Many effects units were developed to produce similar sounds, such as chorusChorus effect
In music, a chorus effect occurs when individual sounds with roughly the same timbre and nearly the same pitch converge and are perceived as one...
, flangers, and phasers
Phaser (effect)
A phaser is an audio signal processing technique used to filter a signal by creating a series of peaks and troughs in the frequency spectrum. The position of the peaks and troughs is typically modulated so that they vary over time, creating a sweeping effect...
, all of which use an oscillating delay (or, in the phaser, a variable phase network).
Arrival of digital technology
ADT became the standard recording studio technique for simulating double tracking throughout the late 1960s and 1970s until the arrival of digitalDigital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
technology in the 1980s (although not all engineers could apparently figure out how to reproduce the effect successfully, with Jack Douglas
Jack Douglas (record producer)
Jack Douglas is an American record producer. He was born in New York City. Starting out as folk musician and performer, he worked on Robert Kennedy's senatorial campaign as a song-writer. Douglas then moved to England and joined a succession of bands before returning to New York to attend the...
recalling that he was at a loss when John Lennon asked him to use ADT on his vocals during a recording session in 1980 but was unable to adequately explain to his producer how the tape decks should be set up to create the effect). With the advent of digital recording, tape- and analog-based delay methods have not been much used, though many of these analog techniques are frequently emulated using comparable digital techniques, or in some cases plugins which are used to extend the capabilities of a Digital audio workstation
Digital audio workstation
A digital audio workstation is an electronic system designed solely or primarily for recording, editing and playing back digital audio. DAWs were originally tape-less, microprocessor-based systems such as the Synclavier and Fairlight CMI...
. Although using digital delay to simulate double-tracking produces a very similar effect to ADT, some claim to be able to hear the difference between the two (certainly one can tell the difference between digital delay and manual double-tracking, as was the case with ADT in previous years – manual double-tracking continues to be used by a number of artists). Some musicians and engineers may casually use the term ADT to refer to any form of simulated double tracking, including digital delay used in this manner, although strictly speaking the term should refer to the analogue technique. One of the very few examples of ADT being used in recent times is on the Beatles' Anthology
The Beatles Anthology
The Beatles Anthology is the name of a documentary series, a set of three double albums and a book focusing on the history of The Beatles. Paul McCartney, George Harrison and Ringo Starr all participated in the making and approval of the works, which are sometimes referred to collectively as the...
albums from the mid-1990s, on which George Martin and Geoff Emerick
Geoff Emerick
Geoffrey Emerick is an English recording studio audio engineer, who is best known for his work with The Beatles' albums Revolver, Sgt. Pepper's Lonely Hearts Club Band, The Beatles and Abbey Road...
decided to revive the analogue technique rather than simply use the modern digital alternatives in order to achieve a more authentic sound, feeling that ADT produced a warmer, less synthetic sound than digital delay and the latter would be inappropriate for use on recordings made on analogue equipment in the 1960s.