12 Bar Blues
12 bar blues is one of the most popular chord progressions and is most notably used in blues songs but, since most popular music today came from the blues, is also widely used in other genres of music. The more you get used to the 12 bar blues progression you’ll also find that many other rock and pop progressions have their foundation built on it even though they differ slightly.
Here is the 12 bar blues progression.
It starts on the I (or tonic) for four measures then moves up to the IV for 2 measures. This move to the IV (or subdominant) offers some interest to the listener. The progression then moves back down to the I for two measures providing some relief from the previous assent. As soon as you’re feeling back at home the V chord takes over for 2 bars and descends down to the IV chord for another two bars which finally returns to the I chord
Commonly Used Extended Chords
While you could play the blues progression with simple major triads like the above example it’s generally played with all dominant 7th chords. While this isn’t exactly diatonic to the key (the I7 & IV7 are not diatonic chords in a major key) it makes for a more bluesy sound and is provides the notes and support needed for improvising with the blues scale. Without these 7th chords a blues scale would sound a little out of place because it contains those 7ths.
For a more mature and complex sound a lot of people opt for 9 chords instead of the dominant 7ths. 9 chords contain the dominant 7 scale degree but also add the 9th degree.
Improvising Over The 12 Bar Blues
More to come…