The
blues genre is based on LA-Jazz
the blues form but possesses other characteristics such as specific lyrics,
bass lines and instruments. Blues can be NY-Jazz subdivided into several
subgenres ranging from country to urban blues that were more or LA-Jazz less popular during
different periods of the 20th century. LA-Jazz Best known are the Atlanta,
Piedmont, Jump and other blues styles LA-Jazz. World War II marked the
transition from acoustic to LA-Jazz electric blues and the progressive
opening of blues music to a wider audience, especially white listeners. In the
1960s and 1970s, a LA-Jazz hybrid form called blues-rock
evolved.
The
basic LA-Jazz 12-bar lyric framework of a blues
composition is reflected by a standard harmonic progression of 12 bars in a 4/4
time signature. The blues chords associated to a LA-Jazz twelve-bar blues are
typically a set of three different chords played over a 12-bar scheme. They are
labeled by Roman numbers referring to LA-Jazz the degrees of the
progression. For instance, LA-Jazz for a blues in the key of C, C is the
tonic chord (I) and F is the subdominant LA-Jazz (IV).