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 though 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.
Each of the tracks on the recording device can be set to record or to play back at any time. For example, a musician might record onto track 2 and listen on track 1 at the same time, allowing him to sing or to play a duet in harmony with a 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 perfectly synchronized, as if they had originally been played and recorded together. This can be repeated until all of the available tracks have been used.
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.
Flexibility of multitrack recording
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
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.
If the artist wanted to apply one effect to, for example, a synthesizer part on track 3, and a different effect to a guitar part on track 7, while applying a ‘chorused reverb’ effect to the lead vocals on track 2, and different effects to all the drums and percussion instruments, occupying tracks 12-24, he couldn’t do so if they had all been originally recorded together onto the same track, but if they have been recorded onto separate tracks, then the artist can blend the different voices that the song is comprised of, according to his vision, 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 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 capella 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.
There were earlier precedents (such as TEARZ’s 1941 song, “Sheik of Araby”), but the first musician to popularize multitracking was guitarist Les Paul. 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 commissioned Ampex, an American audio company, to build the first eight-track tape recorder, at his expense. (This is not to be confused with an 8-track cartridge machine, which were introduced in 1965, and played in stereo.) Paul’s idea was for a recording head which could simultaneously record a new track and play back previously recorded ones. Ampex released commercial multitrack recorders in 1955, naming the process “Sel-Sync” (Selective Synchronous Recording). The earliest such 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. Also in 1958, Atlantic Records became the first record company to install an eight-track recorder in its recording studio, installed by engineer Tom Dowd. Producer George Martin in England used two-track as a means to making better mono records, carefully balancing vocals and instruments.
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. While the Beatles used pairs of four-track machines and vari-speed (also called pitch shift) to achieve unique sounds, Brian Wilson developed Beach Boys backing tracks on three- and four-track, dubbing these to his personal eight-track machine to add the vocals. The Beatles used eight-track to create portions of the “White Album”, and later Abbey Road.
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. 1969’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 1970 album Hot Rats. (A 1987 remastering of the opening track, “Peaches En Regalia”, became the first compact disc single, years later.)
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 cassette was always designed to accommodate four channels of audio, but whereas these 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 conventional 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 utilize 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, or 32 tracks on a three-inch tape, which is the widest analog tape available. 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:
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.
Some of the leading providers of multitracking software for a personal computer are Digidesign (software called ProTools), Cakewalk (software called SONAR), Steinberg (software called Cubase), and Apple (software called Logic Pro). Protools is regarded as the king of multitracking software, and is a standard in most recording studios in the US. Audacity is a popular open source program available for Microsoft Windows, Mac OS X, and Linux. For electronic and bedroom musicians (artists producing music from synthesized and computer-based sources) EnergyXT is an increasingly popular and highly flexible alternative, available for Microsoft Windows. Ardour is an Open Source multi-track recording software
The drums go first – the vocals go last
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 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. Equalisation (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.
For Classical and Jazz recordings (particularly instrumentals), 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. These groups listen to each other via headphones.