Blues chord progressions: some harmonic options.
Hi everyone, in this lesson we will explore some of the countless harmonic options available when playing the blues, from the basic chord progression to the harmonically more complex ones, mainly used in jazz contexts.
First of all the 12 bar blues, in its oldest form, is based exclusively on the tonic - subdominant - dominant relation, i.e. I-IV-V, as shown below here.
The I degree, found in the first four bars, is followed on bar 5 and 6 by the subdominant IV, and back to the I degree on the next two. In the last four bars the dominant - tonic tension is created by playing V7 followed by I7. As you might have noticed, the same dominant 7th chord is played throughout the blues, regardless of the degree.
So, what can you play on dominant 7th chords? Your first choice notes are obviously the chord tones, i.e. tonic, major third, perfect fifth and minor seventh, but keep in mind that, when writing or improvising your own bass-line, you should put the most emphasis on the triad notes (to know more about this, check my major triad blues lessons here). Since the dominant 7th derives from the Mixolydian scale, you can use occasionally also the scale notes, but be careful to place the non-chord tones (major second, perfect fourth and major sixth) on the weak beats, namely the second and fourth. Especially when improvising, other obvious choices are the pentatonic major, minor and the blues scale.
Since there’s no resolution to a major chord, like we would normally find in other music genres, I like to think that the blues is a “democratic” music art form, even if, on a different level, we cannot deny that the tonic - subdominant - dominant relation establishes a ruling position in favor of the tonic.
Despite being the most basic and old one, the previous chord progression is admittedly not too common these days. In order to break the monotony of four consecutive bars on the I degree, in the second bar is often found the IV7, and on bar 9 and 10 the dominant V7 is followed by subdominant IV7, as you can see below here.
A quick note about the African roots of the blues: besides the obsessive repetition of the same chord progression, clear reminiscence of the cyclical form of African music, it’s worth noticing that the subdominant IV7 on bar 2 breaks the “monotony” of the tonic, re-establishing symmetrical blocks of two bars.
In this regard, it’s interesting to note that quite a number of African artists feel that the 12 bar blues is uneven and “contrary to the idea of a regular division of the total cycle” (African Music by Gerhard Kubik, vol.II). As a matter of fact, African artists pretty often tend to cut the first two bars, correcting the blues form to ten bars, as shown here.
If you want to read and know more about African music, I suggest a very thorough study by Gerhard Kubik, “African Music”, voll. I and II.
Moving on to more complex chord progressions used in jazz contexts, we find the following one.
In the fourth bar we can play a V-I, that can be viewed as a IImin7-V7, creating therefore a very strong tension to the IV degree. The next interesting chord is the diminished one on bar 6. To explain its harmonic function I will cite a passage from Schoenberg “Theory of Harmony”: the most important and simplest function of the diminished seventh chord is, namely, not its resolution by means of root movement a fourth upward (VII to III), but rather its resolution in the manner of a deceptive cadence: the root goes up a step (VII to I). Adapting his view to the present case, we can say that this new root resolves imaginatively down a step, before moving back to I7, as we can see following here.
Bars 8, 9 and 10 are nothing more than a sequence of IImin7-V7, starting from the major third of the I degree, and winding back to it on bar 11. The last two bars are based on the very common turnaround I-VImin7-IImin7-V7.
The following one is another harmonic variation based mainly on the same ideas as the one previous one.
Lastly, it’s worth mentioning a slightly different blues from the Be-Bop era: the chord progression used by Charlie Parker in “Blues for Alice”. For the first time a blues was built around major7th chords, re-establishing therefore a sort of hierarchy between the dominant V7 and the Imaj, as you can see in the following picture.
Starting from bar 2, a series of IImin7-V7, each descending a whole step, resolve to the IVmaj7; this same chord is converted into a minor (modal interchange), adopting the function of a new IImin7, and igniting a new series of IImin7-V7, each descending half a step and resolving to the Imaj7 on bar 11. In the last two bars we find the so called “Tad Dameron” turnaround, based either on dominant 7th or maj7 chords.
To wrap up, consider that, even if there are countless chord progressions that can be modeled on a 12 bar blues, all the harmonic variations are nonetheless ascribable to the II-V-I progression, the staple of jazz music.