In Vocal Jazz, Scat singing is a form of vocal improvisation with wordless vocables, nonsense syllables or without words at all.
Scat singing is a much harder technique than it would seem to be, and would require vocalists to sing with improvised melodies and rhythms using their voice as an instrument rather than a speaking medium.
Scat style singing is improvised, the melodies are usually variations on scale and arpeggio fragments, stock patterns and riffs, as is the case with instrumental improvisers.
There is usually some kind of musical structure to Scat, Ella Fitzgerald's performances of "How High the Moon", use the same tempo, begin with a chorus of a straight reading of the lyric, move to a "specialty chorus" introducing the scat chorus, and then the scat itself.
Use of syllables
The deliberate choice of scat syllables also is a key element in Vocal Jazz improvisation, the choice of the correct syllable can be an influences upon the pitch articulation.
Different Jazz singers' would favour different syllables, Betty Carter favoured sounds like "louie-ooie-la-la-la", whilst Sarah Vaughan would tend to use "shoo-doo-shoo-bee-ooo-bee".
Vocalists would also use certain Scat syllables to mimic the sounds of some instruments.
The comparison of styles between Ella Fitzgerald and Sarah Vaughan shiws that Fitzgerald's style reflects the sounds of swing-era Big Bands, she also used to perform with these Big Bands, but Vaughan's sounds like that of the Bebop era small combos that she would perform with.
Humor is a key part of Scat vocals. Cab Calloway regularly shows this. Other great examples would include Slim Gaillard, Leo Watson, and Bam Brown's 1945 "Avocado Seed Soup Symphony," in this the vocalists would Scat variations on the word "avocado" for much of the recording.
In addition to this, Leo Watson, frequently drew on nursery rhymes in his scatting.
Ella Fitzgerald, drew on contemporary music in her singing, for example, the classic 1960 recording of "How High the Moon" live in Berlin, she quotes over a dozen songs, including "The Peanut Vendor", "Heat Wave", "A-Tisket, A-Tasket", and "Smoke Gets in Your Eyes".
It would be easy enough to cite a link between the vocal styling of Rap, especially in the context of improvised Rap battles, and the techniques used in Scat, it would be even easier to claim a link between Scat and the techniques used in human Beat-Boxing, where both of these techniques use the human voice a a replacement for or as an accompaniment to the musical instruments, if not as a total replacement of said instruments.
Jazz artist John Paul Larkin (better known as Scatman John) kick started some mid 1990s interest in Scat, when he fused Jazz vocals with contemporary Pop sounds and the rhythms from Electronic Dance Music, he had a huge hit with the track Scatman (Ski Ba Bop Ba Dop Bop) in 1994.
This all carried on during more recent years, due to the continued popularity of Scatman John, and segments in the British television comedy series The Mighty Boosh which featured scat singing (referred to by its performers as "crimping").
The vocalist, Bobby McFerrin's performances have proved that "wordless singing has traveled far from the concepts demonstrated by Louis Armstrong, Gladys Bentley, Cab Calloway, Anita O'Day, and Leo Watson."
Aerosmith's Steven Tyler has even used Scat as a part of many of the band's songs, sometimes performing extended scat solos which work to complement extend guitar solos, or act as solos themselves, sometimes just to replace forgotten lyrics.
Many Hip Hop music artists and Rappers use Scat singing to come up with the rhythms of their Raps. Tajai of the group Souls of Mischief states the following in the book How to Rap: "Sometimes my rhythms come from scatting. I usually make a scat kind of skeleton and then fill in the words. I make a skeleton of the flow first, and then I put words into it." The group Lifesavas describe a similar process. Rapper Tech N9ne has been recorded demonstrating exactly how this method works, in an audio segment covered by The Washington Post. Godfather of Gangsta Rap Eazy-E uses it extensively in his song Eazy Street.
History and influence
It has been proposed that Scat takes its inspiration from traditional African musical traditions. In a lot of traditional African music, "human voice and instruments assume a kind of musical parity" and are "at times so close in timbre and so inextricably interwoven within the music's fabric as to be nearly indistinguishable".
Scat has also been claimed to be similar to the sound poetry found in traditional African-American music, this would also present the theory that Scat is one of the key roots to Rap.
West African music, often converts drum rhythms into vocal melodies, common rhythmic patterns are assigned specific syllabic translations.
Others people have presented the theory that Scat came from Jazz musicians' practice of formulating riffs vocally before performing them instrumentally. There's a saying - "If you can't sing it, you can't play it" which was common place in the early New Orleans Jazz scene.