A typical melody in Western music is built upon an eight note scale, which is most often either major or minor. The minor, or darker, sadder quality comes from the third note of the scale being flattened or lowered from its sibling, the major scale.
The Western based scale is built upon an unequal series of whole and half notes. The blues, however, has been influenced by elements of the typical musical scale from West Africa, which contained 8 equidistant notes, that is, the scale was not made up of alternating whole and half note intervals, but, every note was the exact same distance apart. When combined with the Euro-tradition of major and minor, the result was a hybrid scale which incorporated both a regular third and a lowered third, a regular seventh and a lowered seventh in the scale. This blues scale, comprised of 10 notes instead of 8, is the basis for the characteristic sound of the blues melody: where the third note and the seventh notes of the scale oscillate between their regular and lowered (or flatted) positions.
Because chords are made up of the notes in any particular scale, blues chords then, take on the characteristic of these altered notes. A typical blues song is made up of three chords in a specific relationship. They are called the I (1) chord, the IV(4) chord and the V(5) chord. Depending on what key the blues song is in, the actual notes change, but the relationship of the IV and V chords are based on where the I chord starts.
The easiest example can be seen in the key of C. In C, the I(1) chord is the C chord, the IV(4) chord (four steps up from C, DEF) is the F chord and the V(5) chord is one step up from that, the G chord. So a blues song in the key of C, would use three chords: C, F & G. However, because we are building the chords on the hybrid blues scale, which alternates some notes, the chords take on a darker, more complex progression.
Notice the difference between a simple C, F, G chord progression and one built with on an altered “blues” scale.
Example: C/F/G progression
Example: C/F/G blues progression.
These altered notes give the blues its characteristic earthy, almost sensuous quality.
The simplicity of the chord progression makes the blues predictable, but also easy to play. Regardless of the key, the chords in the most basic blues song are always in a I, IV, V relationship with the root note of the key. It will be a I, IV, V based on starting with a G, an F, an Eb, or a D.
At the heart of all pure blues songs is a formula known as the “12 bar blues”. It uses the three chords (I, IV & V) in a prescribed order. The “12 bar” part refers to the fact that there are 3 lines of music, each containing 4 measures (or bars). The three chords (I, IV and V) fit into the following spots in those 3 lines, 12 bars in this order:
By itself, the progression sounds like this:
Example: 12 bar blues with just piano right hand.
When you add drums, bass and guitar, all playing the same chord changes, you get this:
Example: Same 12 bar blues with full band.
By the time you add a blues melody to the backup, you get this:
Example: Same 12 bar blues, full band with melody.
One more element needs to be presented regarding the structure of a 12 bar blues song. We’ve pointed out before that the lyrics were about heartache and loss. There are thousands of poems out there that do the same thing:
My love, don’t ever leave me, (A)
For leaving would make me sad. (B)
In all my life, I’ve loved just one, (C)
This one love is all I’ve had. (B)
This song lyric, typical of millions of others has a second and fourth line that rhyme (sad & had), while the other two lines (me, one) don’t rhyme at all.
However, in the 12 bar blues, the rhyming scheme is not ABCB or even ABAB. The three lines of text (remember, 3 lines of 4 bars each) have an AAB rhyming scheme. Even simpler than that, the first two lines (AA) are identical lines of texts.
Baby, don’t leave this honey, you know it would make me sad. (A)
Oh, baby don’t leave this honey, you know it would make me sad. (A)
Don’t walk out that door and leave me, your lovin’s the best that I had. (B)
So, let’s put the pieces together. Take your basic sad lyrics about loss, written in three lines, first two identical, third line rhymes. Have the guitar, piano, bass and drums start the12 bars of music in a swing rhythm, using the blues I, IV, and V chords in the blues “formula”.
From there, it’s just a simple step to “Hound Dog” as performed by Elvis Presley, Little Richard’s “Good Golly, Miss Molly,” Tracy Chapman singing “Give Me One Reason” or B.B. King wailing “The Thrill is Gone.” Thousands of blues, jazz and rock songwriters have used this simple “12 bar, 3 chord” scheme to craft their hit song.
One slight variance on the typical 12 bar blues structure happens when the backup musicians suddenly drop out during the first line of 4 measures. This “stop time” creates spaces of silence for the soloist to create a more complex, extended line of music. The stop time generally occurs in only the first line of a verse, extending it from 4 measures to 8 measures, after which, the final 4+4 is presented unaltered. In a stop time presentation, a blues verse might sound like:
Example: Stop Time Blues
The genius of the 12 bar blues formula is its simplicity. Because it is so simple, the passionate plea of the singer and lyrics, the instrumentalist and the improvised melodies can come through. In the predictability, there is comfort. In the comfort, there is connection. In the connection, there is emotional discovery. In the emotional discovery, there is release—for both performer and listener. In this, the blues are a cathartic release, a letting go of the pain by taking it to the level of admittance, even celebration through singing.