By the mid-1960s, the ready availability of the most up-to-date multitrack recorders – which were by then standard equipment in the leading Los Angeles recording studios – enabled Brian Wilson of The Beach Boys to become one of the first pop producers to exploit the huge potential of multitrack recording. During the group's most innovative period of music-making, from 1964 to 1967, Wilson developed elaborate techniques for assembling the band's songs, which combined elements captured on both four-track and eight-track recorders, as well as making extensive use of tape editing.
By 1964, Wilson's increasingly complex arrangements had far outstripped the group's limited musical abilities – singer-guitarist Carl Wilson was the only group member who regularly contributed to these tracking sessions – so Wilson began frequently recording all the instrumental backing tracks for his songs using the team of top-rank professional studio musicians who came to be known as "The Wrecking Crew", but the band themselves still recorded the instrumental backing for certain songs. For the group's landmark Pet Sounds album in 1966, Wilson recorded all the album's elaborate backing tracks using The Wrecking Crew and other session musicians, while the Beach Boys were away touring, but on the song That's Not Me, the Beach Boys themselves played on the instrumental backing; the session musicians typically performed these instrumental tracks as ensemble performances, which were recorded and mixed live, direct to a 4-track recorder.
When the other Beach Boys returned from touring, they moved to Columbia's Hollywood studio, which was equipped with the latest eight-track technology; by this time, Wilson and his engineers had 'reduced' the pre-recorded four-track backing tracks to a mono mix, which was then dubbed onto one track of the eight-track master tape; Wilson then recorded the vocal tracks, assigning one individual track to each of the six vocalists (including soon-to-be permanent member Bruce Johnston), leaving the eighth track available for final 'sweetening' elements, such as additional vocal or instrumental touches, and lastly, all these elements were mixed down to the mono master tape. Nearly all of the Beach Boys' four-track and eight-track masters from this period are preserved in Capitol's archive, allowing the label to release several expansive boxed sets of this music; The Pet Sounds Sessions (1997), includes nearly all the separate backing and vocal tracks from the album, as well as new stereo mixes of all the songs, while the nine-CD The Smile Sessions (2011) features a wide cross-section of the huge amount of instrumental and vocal material (totalling around 50 hours of recordings) that was recorded for the group's never-completed 1967 magnum opus, Smile.
All of the Beatles classic mid-1960s recordings, including the albums Revolver and Sgt Pepper's Lonely Hearts Club Band, were recorded in this way. There were limitations, however, because of the build-up of noise during the bouncing-down process, and the Abbey Road engineers are still justly famed for the ability to create dense multitrack recordings while keeping background noise to a minimum.
4-track tape also led to a related development, quadraphonic sound, in which the four tracks were used to create 360-degree surround sound. Thousands of quadraphonic albums were released in the 1970s including Pink Floyd's The Dark Side of the Moon and Mike Oldfield's Tubular Bells. 'Quad' failed to gain wide commercial acceptance at the time, but it was the direct precursor of the surround sound technology that became standard in home theater systems in the 1990s.
In a professional audio setting today, such as a recording studio, audio engineers may use 64 tracks or more for their recordings, using one or more tracks for each instrument played.
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