Blues is a genre of music originating in the United States. It evolved from field shouts and hollers of slaves in the Deep South, and many of its properties are similar to those of ethnic African music. These characteristics include tumbling strain, call and response structure, and short, repetitive phrases. Blues is also known for its 12-bar chord progression and blue notes, which can be found in a majority of blues songs.
There are distinct blues styles associated with Atlanta, Chicago, Detroit, the East Coast, Kansas City, Louisiana, Memphis, Mississippi, the Mississippi Delta region (Chicago blues is essentially an electric version of it), New Orleans (which is separate from Louisiana blues), St. Louis, Texas, and the West Coast, as well as a harder form called blues rock that combines the genre with rock and roll (as indicated by the name) and is not specific to any region.
Common Characteristics of Blues
In modern blues the tumbling strain and call and response are usually combined together in a three phrase strain. The famous 12-bar format lends itself directly to this type of phrase structure: music phrases are often 4 bars long, which makes for 3 phrases per chord cycle. The first two phrases are based around the root chord, and the third line is based around the dominant chord in the scale.
There are some variations on the 12-bar format, but the most basic form is as follows:
Phrase one: I I I I Phrase two: IV IV I I Phrase three: V IV I I
This structure is certainly no stranger to variations; among the most common are I-IV-I-I for the first phrase and V-IV-I-V for the last one. If the last chord is the dominant (V), then the last line is called a turn around line, because it turns the phrase around and sets it up for another cycle. Another variation is to make the last bar in each line a seventh chord.
Beginning: Delta Blues
The Delta region southern Mississippi is known as “the land where blues was born.” This is where some of the first forms of blues were recorded in the 1920s; however these recordings did not often represent the sound of live blues at the time (in fact, not every recording by Delta blues legend Robert Johnson has been recovered, and there are not nearly as many as with newer musicians). Live performances were usually a string band, but most recordings from the day were of a solo singer accompanying himself on the acoustic guitar. Nowadays, however, the entire band is recorded, sometimes adding brass and woodwind instruments on top of the standard harmonica (sometimes called a harp) and strings. The Delta style is also known for surge singing, which is short, surging phrases of sound.
Further Migration of Blues
Chicago-style blues was started after the “great migration” of poor black workers into the industrial Northeast and Midwest in the first half of the twentieth century. Chicago style blues is traditional Delta style, but with electric guitar added (usually in place of an acoustic) as well as drums, bass, piano and sometimes saxophone. It has a more electrified and gritty feel than the Delta style, especially if effects like distortion are applied to amplification (which later became a defining trait of late '60s-'70s hard rock, itself descended from electric blues). The addition of amplification makes the music more audible to larger audiences.
After the great migration blues moved across the country; it even was highly influential in the British rock invasion of the ’60s. Almost every modern American genre of music, especially jazz, country, and rock were greatly influenced by, or inseparably linked with blues.