Multitrack recording
Multitrack recording ('multitracking' or just 'tracking' for short) is a method of sound recording that allows for the separate recording of multiple sound sources to create a cohesive whole. This is the most common method of recording popular music.
Multitracking can be achieved with analogue, tape based, equipment (from simple cassette based 4/8 trackers to 2" reel to reel 24 track machines), digital equipment that relies on tape storage of recorded digital data (such as ADAT 8 track machines) and hard disk based systems, often employing a computer and multitrack audio recording software. Multitrack recording devices vary in their specifications, such as the number of simultaneous tracks available for recording at any one time; in the case of tape based systems this is limited by, among other factors, the physical size of the tape employed. For computer based systems the trend is towards unlimited numbers of record/playback tracks, although issues such as memory and CPU available will in fact limit this from machine to machine. It has to be noted that on computer based systems, the number of simultaneously available recording tracks is limited by the sound card discrete analogue or digital inputs.
When recording, audio engineers can select which track (or tracks) on the device will be used for each instrument.
At any given point on the tape, any of the tracks on the recording device can be recording or playing back, so that an artist is able to record onto track 2 and, simultaneously, listen to track 1, allowing him to sing or to play an accompaniment to the performance already recorded on track 1. He might then record on track 3 while listening to track 2. All three performances can then be played back in perfect synchrony, as if they had originally been played and recorded together. This can be repeated until all of the available tracks have been used, or in fact, reused. See "Punching in".
When recording is completed, the many tracks are "mixed down" through a mixing console to a two-track stereo recorder in a format which can then be duplicated and distributed. Most of the records, CDs and cassettes commercially available in a music store are recordings that were originally recorded on multiple tracks, and then mixed down to stereo. These stereo mixes can in turn be recorded onto two tracks of a four-track recorder, allowing additional sound to be layered on the remaining tracks.
Flexibility
During multitracking, multiple musical instruments (and vocals) can be recorded, either one at a time or simultaneously, onto individual tracks, so that the sounds thus recorded can be accessed, processed and manipulated individually to produce the desired results. For example, after recording some parts of a song, an artist might listen to only the guitar part, by 'muting' all the tracks except the one on which the guitar was recorded. If he then wanted to listen to the vocals in isolation, he would do so by muting all the tracks apart from the vocals track. If he wanted to listen to the entire song, he could do so by unmuting all the tracks. If he did not like the guitar part, or found a mistake in it, and wanted to replace it, he could do so by re-recording only the guitar part, rather than re-recording the entire song. This kind of editing freedom is one of the biggest benefits of multitracking.
If all the voices and instruments in a recording are individually recorded on distinct tracks, then the artist is able to retain complete control over the final sculpting of the song, during the mixdown (re-recording to two stereo tracks for mass consumption) phase.
For example, if an artist wanted to apply one effect to a synthesizer part, a different effect to a guitar part, a 'chorused reverb' effect to the lead vocals, and different effects to all the drums and percussion instruments, he could not do so if they had all been originally recorded together onto the same track. However, if they had been recorded onto separate tracks, then the artist could blend and alter all of the instrument's sounds with complete freedom.
Multitrack recording allows a single musician to record multiple parts, allowing duos (such as Ween) and trios (such as Cream) to produce a larger sound, larger groups to double parts or add different instruments, and also a solo performer to create an ensemble sound, playing different parts. Paul McCartney, Todd Rundgren, Trent Reznor, Lenny Kravitz and Prince are among the performers to produce albums in this way, as their own "band". Even a musician who plays no instruments can create a marketable record, as with a cappella artist Bobby McFerrin, who performed all of the parts in his recordings (from 1980 to 2000) vocally.
Multitracking a song also leaves open the possibilities of remixes by future artists, such as DJs. If the song was not available in a multitrack format recording, the job of the remixing artist could be very difficult, or impossible, because once the voices have been recorded together during the mixdown phase, they are inseparable. Theoretically, one could use frequency selective filters for this, but in reality this has not been done to any great degree of success, possibly because of the multi-harmonic (having many frequencies) nature of many musical instruments.
History
There were earlier precedents (such as TEARZ's 1941 song, "Sheik of Araby"), but the person credited with the invention of magnetic audio tape multitracking was guitarist, composer and inventor Les Paul, who also contributed to the famous Gibson Les Paul model electric guitar for Gibson Guitar Corporation in the early 1950s.
Paul had been experimenting with overdubbing in the late 1940s and in 1947, Capitol Records released a record featuring Paul playing eight different parts on electric guitar. These recordings were made with wax disks; Paul would record a track onto a disk, then record himself playing another part with the first.
Paul's invention of multitrack recording was made possible by a gift from his friend Bing Crosby -- an Ampex Model 200, the world's first commercially-produced reel-to-reel tape recorder. These machines were based on modified German Magnetophon recorders which had been acquired by audio engineer Jack Mullin while he was serving in the U.S. Army Signal Corps in the closing days of World War II. Mullin had studied and modified the recorders, hoping to sell the system to the Hollywood movie studios as a new means of recording movie soundtracks.
After hearing a demonstration of Mullin's tape recorders in June 1947, Crosby became a major backer of the new technology — he hired Mullin as his chief engineer and immediately invested US$50,000 in the electronics firm Ampex so that the company could develop a commercial version of Mullin's machines. Crosby became the first performer in the world to pre-record radio broadcasts and master his commercial music recordings on tape.
In 1948 Crosby gave Paul one of the first production units of the new Ampex Model 200 reel-to-reel tape recorder. Within hours, Paul had the idea of modifying the machine by the addition of extra recording and playback heads which could allow him to simultaneously record a new track whilst monitoring the playback of previously recorded tracks.
Paul's multitrack experiments progressed rapidly and in 1953 he commissioned Ampex to build the world's first eight-track tape recorder, at his own expense. (This is not to be confused with an 8-track cartridge machine, an offshoot of the four-track recorder, introduced in 1965, which played in stereo.)
Ampex released the first commercial multitrack recorders in 1955, naming the process "Sel-Sync" (Selective Synchronous Recording). Coinciding the advent of full frequency range recording (FFRR), stereo and the high-fidelity microgroove vinyl LP format, multitrack recorders soon became indispensable to vocalists like Crosby and Nat "King" Cole.
The earliest multitrack recorders were analog magnetic tape machines with two or three tracks. Elvis Presley was first recorded on multitrack during 1957, as RCA's engineers were testing their new machines. Buddy Holly's last studio session in 1958 employed three-track, resulting in his only stereo releases not to include overdubs. The new three-track system allowed the lead vocal to be recorded on a dedicated track, while the remaining two tracks could be used to record the backing tracks in full stereo, and this system was also used extensively by producer Phil Spector in the early Sixties for his famous "Wall of Sound" recordings.
In 1958, Atlantic Records led the world, becoming the first record company to install an eight-track recorder in its recording studio, installed by engineer Tom Dowd. However, recorders with four or more tracks were restricted mainly to American recording studios until the mid-to-late Sixties, mainly due to import restrictions and the high cost of the technology. In England, pioneering independent producer Joe Meek produced all of his innovative early Sixties recordings using monophonic recorders. EMI house producer George Martin was considered an innovator for his use of two-track as a means to making better mono records, carefully balancing vocals and instruments; Abbey Road Studios did not install a four-track recorder until around 1963, and all The Beatles recordings prior to their first world hit single I Want To Hold Your Hand (1963) were made on two-track machines.
Other western countries also lagged well behind the USA -- in Australia, the largest local recording label, Festival Records did not install a four-track recorder until late 1966; the first eight track recorders did not appear there until the late Sixties; Australia's first sixteen track recorder was installed at Armstrong's Studios in Melbourne in 1971; Festival installed Australia's first 24-track recorder at its Sydney studio in 1974.
The artistic potential of the multitrack recorder came to the attention of the public in the 1960s, when artists such as The Beatles and The Beach Boys began to multitrack extensively, and from then on virtually all popular music was recorded in this manner. The technology developed very rapidly during these years. At the start of their careers, the Beatles and Beach Boys each recorded live to mono, two-track (the Beatles), or three-track (the Beach Boys); by 1965 they used multitracking to create pop music of unprecendented complexity.
The Beach Boys' acclaimed 1966 LP Pet Sounds relied on multitrack recorders for its innovative production. Brian Wilson pretaped all the instrumental backing tracks with a large ensemble, recording the performances live, direct to a four-track recorder. These four-track backing tapes were then 'dubbed down' to one track of an eight-track tape. Six of the remaining seven tracks were then used to individually record the vocals of each member of The Beach Boys, and the eighth track was reserved for any final 'sweetening' overdubs of instruments or voices.
Because the Beatles did not gain access to eight-track recorders until later on, their groundbreaking Sgt Pepper's Lonely Hearts Club Band LP (1967) was created using pairs of four-track machines; the group also used vari-speed (also called pitch shift) to achieve unique sounds, and they were the first group in the world to use an important offshoot of multitrack recording, the Automatic Double Tracking (ADT) system invented by Abbey Road staff engineer Kem Townshend in 1966. The Beatles used eight-track to record portions of Magical Mystery Tour, the "White Album", and later Abbey Road. It was during the White Album sessions of 1968 that EMI's Abbey Road Studios finally had eight-track recorders installed, and up until then, the group had to go elsewhere to record with eight-tracks.
Other artists began experimenting with multitrack's possibilities also, with The Music Machine (of "Talk Talk" fame) recording on a custom-built ten-track setup, and Pink Floyd collaborating with former Beatles recording engineer Norman "Hurricane" Smith, who produced their first albums. 1968's "Crimson And Clover" by Tommy James and the Shondells was among the first sixteen-track recordings to be released (mixed to stereo and mono); another was Frank Zappa's 1969 album Hot Rats. (A 1987 remastering of the opening track, "Peaches En Regalia", became the first compact disc single, years later.) Throughout the 1970s Queen experimented with multi tracking extensively most prominently on their albums Queen II and A Night at the Opera.
During the 1970s, sixteen, twenty-four, and thirty-two tracks became common, with recording tape reaching two and three inches (5.08cm - 7.62cm) wide. By contrast, the advent of the compact audio cassette (in 1963) ultimately led to affordable, portable four-track machines such as the Tascam Portastudio which debuted in 1979. Cassette-based machines could not provide the same audio quality as reel-to-reel machines, but served as a useful tool for professional and semi-pro musicians in making song demos. Bruce Springsteen's 1982 album Nebraska was made this way, with Springsteen choosing the album's earlier demo versions over the later studio recordings.
The familiar tape cassette was designed to accommodate four channels of audio -- in a commercially recorded cassette these four tracks would normally constitute the stereo channels (each consisting of two tracks) for both 'sides' of the cassette -- in a four-track cassette recorder all four tracks of a cassette are utilized together, often with the tape running at twice the normal speed for increased fidelity. A separate signal can be recorded on to each of four tracks. (As such, the four-track machine does not utilise the two separate sides of the cassette in the conventional sense; if the cassette is inserted the other way round, all four tracks play in reverse.) As with professional machines, two or more tracks can be bounced down to one. When recording is complete, the volume level of each track is optimized, effects are added where desired, each track is separately 'panned' to the desired point in the stereo field and the resulting stereo signal is mixed down to a separate stereo machine (such as a conventional cassette recorder).
Today, multitrack recorders can be analog or digital, and are available with many more tracks. Analog multitracks can have up to 24 tracks on a tape two inches wide which is the widest analog tape available. Protoype machines using 3" tape for 32 tracks never went into production, though Otari made a 32 track 2" MX-80. Digital multitracks can have an almost unlimited number of simultaneous tracks and can record to and play back from a number of media and formats including digital tape, hard disk, and optical disk. The lower cost has made it easier to find multitrack recording technology outside a typical recording studio. For example, Apple Computer's GarageBand is included in all of the company's new computers, and is used by amateurs as a cost-efficient way to downmix music and podcasts.
Starting around 1995, another revolution in multitracking began, with the arrival of cheap digital multitrack recorders, which recorded sound to a computer hard drive, a digital tape format (such as ADAT), or in some cases Minidiscs. The prices of these machines steadily dropped over time. Meanwhile, the power of the personal computer increased, so that today, an average home computer is sufficiently powerful to serve as a complete multitrack recorder, using inexpensive hardware and software (under US $1000.00). This is a far cry from the days when multitrack recorders cost thousands of dollars and few people could afford them.
Some of the leading providers of multitrackers are Tascam (hard drive or cassette based), Alesis (ADAT digital tape based), Roland (hard drive based), Fostex (hard drive based) and Yamaha (hard drive based).
Using a personal computer as a multitrack recording device
Today, a sufficiently dedicated and talented artist can literally produce a million selling album in his own bedroom, using only his personal computer as a professional tracking machine. This has been done by many artists already, such as Mylo and Daniel Bedingfield. In order to use a personal computer as a multitracking device, a minimum of three items are required:
- A personal computer which has a sound card
- Multitrack recording software installed and running on the computer (suitable software is available at low prices or even free, in the case of Free and Open Source Software)
- At least one or more recording sources such as a musical instrument like a guitar or a synthesizer, a good microphone to record the vocals of a singer and/or any other sources of sound to be recorded.
This is all that is needed to set up a multitracking studio at home capable of producing high quality recordings. The standard sound card in a personal computer can be used to capture sounds. This is done simply by attaching either a microphone to the microphone input jack if a vocal track is to be recorded, or by attaching a stereo cable from the electronic device (such as a synthesizer or a guitar amplifier) to the line input of the sound card. Computers with appropriate software and hardware can record multiple audio tracks at once. This audio interface hardware sends audio signals to the computer and may inteface with the computer via a PCI card, USB or firewire connections.
The instruments and singers' voices are recorded onto individual files on the computer's hard drive, which function as tracks as per traditional multitracking.
Effects such as reverb, chorus, delays can be applied by the computer software. When the musicians are happy with the sound, the multiple tracks are mixed down onto two clean tracks, again within the multitracking software. Finally, the final stereo recording can be burned to a CD, which can then be copied and distributed.
Leading multitracking software for a personal computer includes: ProTools from Digidesign, SONAR from Cakewalk, Cubase from Steinberg, and Logic Pro from Apple. ProTools is regarded as the king of multitracking software, and is a standard in most recording studios worldwide.
Audacity and Ardour are popular open source programs for multi-track recording. Jokosher (open source as well) is quite new, but seems to gain popularity among Linux users.
Order of recording
In most modern popular songs, drums and percussion instruments are the first instruments to be recorded. There are various reasons for this. The drums are usually the rhythm leaders; it is much easier for musicians recording later tracks to keep to the common beat of the drums. A drummer would find it very difficult to play along with a backing track recorded without percussion, due to the likely variations in the musicians' tempo. Furthermore, in order to accurately keep to a pre-established rhythm, a drummer would need the sound of the other instruments to be very loud to compete with his drum kit; apart from the possibility of the drum microphones picking up the sound of the other instruments from the drummer's headphones, prolonged exposure to such volume might very well damage his/her hearing. Also, it allows the drums to be recorded for a few seconds, then looped.
Also, though the drums might eventually be mixed down to a couple of tracks, each individual drum and percussion instrument might be initially recorded to its own individual track. The drums and percussion combined can occupy the largest number of tracks utilized in a recording. This is done so that each percussion instrument may be processed individually for maximum effect. A common percussion effect is the slow back and forth panning of a percussive instrument's sound in the stereo field from the left to the right channel in a song. Equalization (or EQ) is often used on individual drums, to bring out each one's characteristic sound.
The last tracks to be recorded are usually the vocals (though a temporary vocal track might be recorded early on either as a reference or to guide subsequent musicians). One reason for this is that singers will often temper their vocal expression in accordance with the accompaniment and vice versa.
Concert music
For Classical and Jazz recordings (particularly instrumentals) where multitracking is chosen as the recording method (as opposed to direct to stereo, for example), a different arrangement is used; all tracks are recorded simultaneously. Sound barriers are often placed between different groups within the orchestra, e.g. pianists, violinists, percussionists, etc. When barriers are used these groups listen to each other via headphones.
See also
- Digital audio workstation
- Remix
- Reverb
- Musical Instrument Digital Interface (MIDI)
- Module file
- Various sound effects including chorus, compression, delays, flanger, phaser etc.
- Tracker