Multitrack recording
Multitrack recording (MTR), also known as multitracking, is a method of sound recording developed in 1955 that allows for the separate recording of multiple sound sources or of sound sources recorded at different times to create a cohesive whole. Multitracking became possible in the mid-1950s when the idea of simultaneously recording different audio channels to separate discrete tracks on the same reel-to-reel tape was developed. A track was simply a different channel recorded to its own discrete area on the tape whereby their relative sequence of recorded events would be preserved, and playback would be simultaneous or synchronized.
A multitrack recorder allows one or more sound sources to different tracks to be simultaneously recorded, which may subsequently be processed and mixed separately. Take, for example, a band with vocals, guitars, a keyboard, bass, and drums that are to be recorded. The singer's microphone, the output of the guitars and keys, and each individual drum in the kit can all be recorded separately using a multitrack recorder. This allows each track to be fine-tuned individually, such as increasing the voice or lowering the chimes, before combining them into the final product.
Prior to the development of multitracking, the sound recording process required all of the singers, band instrumentalists, and/or orchestra accompanists to perform at the same time in the same space. Multitrack recording was a significant technical improvement as it allowed studio engineers to record all of the instruments and vocals for a piece of music separately. Multitracking allowed the engineer to adjust the levels and tone of each individual track, and if necessary, redo certain tracks or overdub parts of the track to correct errors or get a better take. Also, different electronic effects such as reverb could be applied to specific tracks, such as the lead vocals, while not being applied to other tracks where this effect would not be desirable (e.g., on the electric bass). Multitrack recording was much more than a technical innovation; it also enabled record producers and artists to create new sounds that would be impossible to create outside of the studio, such as a lead singer adding many harmony vocals with their own voice to their own lead vocal part, an electric guitar player playing many harmony parts along with their own guitar solo, or even recording the drums and replaying the track backwards for an unusual effect.
In the 1980s and 1990s, computers provided means by which both sound recording and reproduction could be digitized, revolutionizing audio recording and distribution. In the 2000s, multitracking hardware and software for computers was of sufficient quality to be widely used for high-end audio recordings by both professional sound engineers and by bands recording without studios using widely available programs, which can be used on a high-end laptop computer. Though magnetic tape has not been replaced as a recording medium, the advantages of non-linear editing (NLE) and recording have resulted in digital systems largely superseding tape. Even in the 2010s, with digital multitracking being the dominant technology, the original word track is still used by audio engineers.
Flexibility[edit]
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. In the 2010s, many rock and pop bands record each part of the song one after the other. First, the bass and drums are often recorded, followed by the chordal rhythm section instruments. Then the lead vocals and guitar solos are added. As a last step, the harmony vocals are added. On the other hand, orchestras are always recorded with all 70 to 100 instrumentalists playing their parts simultaneously. If each group of instrument has its own microphone, and each instrument with a solo melody has its own microphone, the different microphones can record on multiple tracks simultaneously. After recording the orchestra, the record producer and conductor can adjust the balance and tone of the different instrument sections and solo instruments, because each section and solo instrument was recorded to its own track.
With the rock or pop band 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 one then wanted to listen to the lead vocals in isolation, one would do so by muting all the tracks apart from the lead vocals track. If one wanted to listen to the entire song, one could do so by un-muting all the tracks. If one did not like the guitar part, or found a mistake in it, and wanted to replace it, one could do so by re-recording only the guitar part (i.e., re-recording only the track on which the guitar was recorded), rather than re-recording the entire song.
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 mix-down (re-recording to two stereo tracks for mass distribution) phase. For example, if an artist wanted to apply one effects unit 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, they 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 and vocal sounds with complete freedom.
Multitracking a song also leaves open the possibilities of remixes by the same or future artists, such as DJs. If the song was not available in a multitrack format recording, the job of the remixing artist was very difficult, or impossible, because, once the tracks had been re-recorded together onto a single track ('mixed down'), they were previously considered inseparable. More recent software allows sound source separation, whereby individual instruments, voices and effects can be upmixed — isolated from a single-track source — in high quality. This has permitted the production of stereophonic or surround sound mixes of recordings that were originally mastered and released in mono.
Order of recording[edit]
In modern popular songs, drums, percussion instruments[6] and electric bass are often among the first instruments to be recorded. These are the core instruments of the rhythm section. Musicians recording later tracks use the precise attack of the drum sounds as a rhythmic guide. In some styles, the drums may be recorded for a few bars and then looped. Click (metronome) tracks are also often used as the first sound to be recorded, especially when the drummer is not available for the initial recording, and/or the final mix will be synchronized with motion picture and/or video images. One reason that a band may start with just the drums is because this allows the band to pick the song's key later on. The producer and the musicians can experiment with the song's key and arrangement against the basic rhythm track. 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 a large number of tracks utilized in a recording. This is done so that each percussion instrument can be processed individually for maximum effect. Equalization (or EQ) is often used on individual drums, to bring out each one's characteristic sound. The last tracks recorded are often the vocals (though a temporary vocal track may be recorded early on either as a reference or to guide subsequent musicians; this is sometimes called a guide vocal, ghost vocal or scratch vocal). One reason for this is that singers will often temper their vocal expression in accordance with the accompaniment. Producers and songwriters can also use the guide/scratch vocal when they have not quite ironed out all the lyrics or for flexibility based on who sings the lead vocal (as The Alan Parsons Project's Eric Woolfson often did).
Concert music[edit]
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.
Multitrack live recording is a lot like gigging – a lot of planning ahead of time, a lot of gear to carry and set up, a lot of waiting, and then a lot of hectic activity over the next 40 minutes or so! There is little doubt that a pseudolive studio performance can enhance certain forms of music, particularly those with a lot of intensity in the live performance, but it still lacks the atmosphere of a real gig. You may record the moment with a portable setup during the performance. You can produce wonderful live recordings with just two microphones and a building's inherent acoustics, but that will have to wait for another day. Taking a feed from the front of house (or FOH) desk directly to tape or DAT is another technique of live recording, although this will only work in large venues where everything is run through the PA system. Even so, a loud backline will result in less guitar and bass being routed via the main PA system, resulting in an unbalanced mix. A multitrack recording has distinct advantages: it allows you more control after the event because you may fine-tune the mix and correct any obvious mistakes without sacrificing the thrill of the live performance. It does, however, necessitate a lot more pre-gig planning as well as a lot more equipment.