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Most blues researchers claim that the very early blues were patterned
after English ballads and often had eight, ten, or sixteen bars. The blues now consists of a definite progression of harmonies
usually consisting of eight, twelve or sixteen measures, though the
twelve bar blues are, by far, the most common.
The 12 bar blues harmonic progression (the one-four-five) is most often
agreed to be the following: four bars of tonic, two of subdominant, two
of tonic, two of dominant, and two of tonic. Each roman numeral indicates a chord built on a specific tone in the major scale. Due to the
influence of rock and roll, the tenth chord has been changed to IV. This alteration is now
considered standard. In practice, various intermediate chords, and even some substitute chord patterns, have been used in blues
progressions, at least since the nineteen-twenties. Some purists feel that any variations or embellishments of the basic blues pattern
changes its quality or validity as a blues song. For instance, if the basic blues chord progression is not used, then the music being played
is not the blues. Therefore, these purists maintain that many melodies with the word \"blues\" in the title, and which are often spoken of as
being the blues, are not the blues because their melodies lack this particular basic blues harmonic construction.
The principal blues melodies are, in fact, holler cadences, set to a
steady beat and thus turned into dance music and confined to a
three-verse rhymed stanza of twelve to sixteen bars. The
singer can either repeat the same basic melody for each stanza or
improvise a new melody to reflect the changing mood of the lyrics. Blues rhythm is also very flexible. Performers often sing
\"around\" the beat, accenting notes either a little before or behind the
beat.
Jazz instrumentalists frequently use the chord progression of the
twelve-bar blues as a basis for extended improvisations. The twelve or
sixteen bar pattern is repeated while new melodies are improvised over
it by the soloists. As with the Baroque bassocontinuo, the repeated
chord progression provides a foundation for the free flow of such
improvised melodic lines.
Conclusion
One of the problems regarding defining what the blues are is the variety
of authoritative opinions. The blues is neither an era in the
chronological development of jazz, nor is it actually a particular style
of playing or singing jazz. Some maintain (mostly musicologists) that the blues are defined by the use of blue notes (and on this point they
also differ - some say that they are simply flatted thirds, fifths, and sevenths applied to a major scale; some maintain that they are
microtones; and some believe that they are the third, or fifth, or seventh tones sounded simultaneously with the flatted third, or fifth, or
seventh tones respectively). Others feel that the song form is the defining feature of the blues. Some
feel that the blues is a way to approach music, a philosophy, in a
manner of speaking. And still others hold a much wider sociological view
that the blues are an entire musical tradition rooted in the black
experience of the post-war South. Whatever one may think of the social
implications of the blues, whether expressing the American or black
experience in microcosm, it was their \"strong autobiographical nature,
their intense personal passion, chaos and loneliness, executed so
vibrantly that it captured the imagination of modern musicians\" and the general public as well.
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