The Swingles are an a capella vocal group. The Swingle Singers originally formed in 1962 in Paris under the leadership of Ward Swingle. In 1973, Swingle disbanded the French group, and formed an English group known initially as Swingle II and later as the New Swingle Singers, before settling on the Swingles name. They did a fair amount of classical stuff, Bach and other composers, jazz and 50s Music, also the Beatles, a wonderful version of Blackbird.
Ward Swingle created the group to meld Bach and scat singing. One of the few groups to be a truly living organism. Each member only stays with them 3-7 yrs or so. Since it's inception there have been over 120 members. Each member bringing with them and leaving behind unique styles, songs, and arrangements.