12 Bar Blues
You might have heard of the blues, made famous as a way to make a living in the US for marginalized citizens.
The story goes that the French taught the Black community music theory and unlocked a creative juice thirsting for expression.
12 bar blues is very basic music lesson and is known universally by musicians as a way to quickly join other musicians musically.
Scales: a quick primer 🎼
The most common western scale - the major scale - has 7 notes representing pitch.
In any key or scale, they can be referred to by roman numerals:
I · II · III · IV · V · VI · VII
In C major the note names are:
Rhythm: a quick primer 🥁
Rhythm time signatures consist of beats per bar.
A bar is a measure of time for beat duration’s (quarter note ♩, eighth note ♪, etc).
The most popular time signature 4/4 is also called common time. Each bar consists of 4 beats of quarter notes (♩ = 1/4). It can be vocalized simply as
one, two, three, four.
A time signature of 5/8 would mean 5 beats of eighth notes (♪ = 1/8). It can be vocalized as
one and two and three and four and five.
12 bar blues: Chords
The chords used in the 12 bar blues are the root, fourth and fifth (I · IV · V).
Using these basic melodic notes we can create a rhythm pattern for any key.
In key of C from the example on scales, the notes used would be: C · F · G.
The chord progression starts out simple and progressively gets more complicated before repeating.
12 bar blues: Rhythm and Changes
As a intro, the 12 bar blues rhythm formula looks like
4 · 2 · 2 · 1 · 1 · 1 · 1
It is in terms of bars per chord progression (4 bars of a chord followed by two bars of another and so on). The total of these values is 12 hence the title 12 bar blues
If we apply the roman numerals I · IV · V from the 12 bar chords to this pattern it looks more like:
I I I I · IV IV · I I · V · IV · I · V
Which is four bars of the first, two bars of the fourth, and so on.
You might also find it interesting to see a pattern with 4 and its sums:
4 = 2 + 2 = 1 + 1 + 1 + 1
Bringing it on home 🎸
Applying note values to the previous pattern in the key of C, the 12 bar blues now looks like:
C C C C · F F · C C · G · F · C · G
To break that down:
- four bars of C (I)
- two bars of F (IV)
- two bars of C (I)
- one bar of G (V)
- one bar of F (IV)
- one bar of C (I)
- one bar of G (V) - also called the ‘turnaround’ back to the beginning.
Oh, how convenient, that is also 7 key changes, just like the number of notes in a scale. Lucky 7 I guess.
Practising and Next
Get a feel for the notes, and use a metronome to count the rhythm per bar as you play them. Most people will play using the minor pentonic scale (I · flat III · IV · V · flat VII).
Jazz Blues is a variation that I will leave to another post. Not quite sure which came first, but I would wager it would be a predecessor to the 12 bar blues.
There is also a lot of other things you can do to add flavor to the blues.
- ‘Walking’ the notes in the scale
- lead in/lead out notes
- ‘turnaround’ riffs
- rhythm changes
- pattern variations
- solo in different modes (dorian is nice)