Blues
Blues combines a repeating harmonic form, flexible pitch and a groove that can sit between straight and swung subdivision. Its central sound comes from the friction between dominant-seventh harmony and melodies that bend or shade the third, fifth and seventh.
- 12-bar form
- I7 IV7 V7
- blue notes move between fixed pitches
Where you run into this
- Blues
- Rock
- Jazz
- Soul
Why are all three chords dominant sevenths?
In common-practice harmony, a dominant seventh usually points toward another chord. In blues, I7 can function as home while IV7 and V7 organize the form around it.
That means the chord quality is part of the style's color, not a promise that every seventh will resolve by textbook voice leading.
How does the 12-bar form work?
| Bars | Chord area | Function in the form |
|---|---|---|
| 1-4 | I7 | establish the tonic and vocal statement |
| 5-6 | IV7 | move away and answer |
| 7-8 | I7 | return to tonic |
| 9 | V7 | strongest push |
| 10 | IV7 | step back toward home |
| 11-12 | I7, often with turnaround | close and launch the next chorus |
Variations change bars, substitutions and turnaround, but players need the bar map to stay together.
What is a blue note?
Blue notes are flexible melodic regions, especially around the minor third, diminished fifth and minor seventh relative to the tonic. Singers and instrumentalists can bend through those regions instead of treating them as twelve fixed keyboard points.
Play E-flat over C7, then move slowly toward E-natural. The expressive space between them is central to the sound. The melody can shade the minor third while the chord contains a major third.
Straight, swing and shuffle are different
A shuffle divides each beat into a long-short pair related to triplets. Swing can vary by tempo, player and subdivision. Straight eighths divide the beat evenly.
Keep the bar and backbeat stable while changing subdivision. The groove should remain countable even when the notes lean.
Build one blues chorus
- Count 12 barssay each chord area before playing.
- Add the backbeatclap beats 2 and 4.
- Choose one three-note phraseanswer it in bars 3 and 4.
- Bend the thirdmove between minor and major color.
- Write a turnaroundmake bars 11 and 12 point to the next chorus.