User:Alexbirger1/Twelve-bar blues

History
The blues comes from the south and brings together a combination of work songs, spirituals, and early southern country music. The music was passed down through oral tradition. It was first written down by W.C Handy, an African American band leader. It's popularity lead to the creation of "race records" and the popularity of blues singers like Bessie Smith and Ma Rainy. Race records was later renamed "Rhythm and Blues" which is where we get the modern day genre of of R&B. As the music became more popular more people wanted to make it. General patterns that existed in the blues were formalized, on of these being the 12-bar blues.

Melodic Line
As the chords of a 12 bar blues follow a form, so do the the melodic line. The melodic line might just be the melody of the piece or it might also include lyrics as well. The melody and lyrics frequently follow an AA'B form meaning, one phrase is played; then it is repeated, maybe with a slight alteration; then, something new is played. Using "Hound Dog" as an example, made famous by Elvis Pressly, but was originally a blues song sung by Big Mamma Thorton it can show this AA'B form in practice. The Song starts out with “You ain't nothin' but a hound dog, Cryin' all the time” then the phrase repeats with slight melodic embellishment or subtle change “You ain't nothin' but a hound dog, Cryin' all the time”, then finally something new happens “Well, you ain't never caught a rabbit, And you ain't no friend of mine”. This pattern continues throughout the song. This pattern is used frequently in the blues and is also used in many genre that have their roots in the blues.

Seventh chords
Seventh chords are a a type of chord that includes the 7th scale degree other wise known as the 7th note of the scale. There are different types of 7th chords such as: Major 7ths, Dominant 7ths, Minor 7ths, Half diminished 7ths, Fully diminished 7ths. These chords are similar with slight changes, but are all centered around the same key center. Dominant 7th chords are generally used throughout a blues progression. The addition of dominant 7th chords as well as the inclusion of other types of 7th chords (ie. minor and diminished 7ths) are often used just before a change, and more changes can be added. A more complicated example might look like this, where "7" indicates a seventh chord: