Improvising blues chords

Question

I understand the concept of the blues scale and its blue notes flat 3rd flat 5th and flat 7th, my question is: What chords can you use to accompany the blues because I'm tired of just staying on the I IV V.

In other words the major scale has a chord scale match up in the key of C: C, Dmin, Emin, Fmaj7, G7, Amin, Bminflat5.

What would be the chords for the blues scale in C? C?, Eflat?, F? Fsharp?, G?, Bflat?

Answer 1

Tonal harmony does provide some ways to further develop harmonic patterns in blues, but with some specificities.

The secondary dominant is a concept borrowed from classical harmony that's widely used in jazz blues. This may be taken an additional step further with the commonly used in Jazz ii-V-I progression.

So, for a basic 12 bar blues progression

I   I   I   I
IV  IV  I   I
V   V   I   I

We can introduce a ii-V-I (applied to the concept of secondary dominant, secondary sub-dominant or, more generically "local key") for each change in harmonic function:

I      I      I     ii/IV V/IV    <--- ii-V-I to approach the subdominant
IV     IV     I     I
ii     V      I     I       <--- here we already have V-I, just add the ii before the dominant

Further harmonic development can be:

I      IV     I     ii/IV V/IV    <--- simple I-IV-I- progression
IV     IV     I     V/ii          <- secondary dominant to approach the ii
ii     V      I     ii V      <--- introduce "turnaround" with ii-V-I of the tonic proper

This is, I think, some times called a "basic blues progression", to distinguish from the more simple, so more generic blues progression.

As I understand, so far we have only used techniques that could have been used by any composer of the classical period, to introduce harmonic development and increase harmonic rhythm. As I said, secondary dominants, passing chords, and the ii-V-I progression is nothing more in essence than a circle of fifths progression.

The blues specificities come of course from the generic use of 7th chords in all scale degrees and chords, and the voice leading applied. Not that the general classical rules of voice leading (keep common tones, move by steps, etc.) are not generically followed, but because of the special focus given to the so called guide tones (the 3rds and 7ths of all chords).

So, to be clear, let's put the example in chord names, for example in C, rather than roman numerals:

C7    F7    C7    Gm7 C7 <-- C does not function here as tonic but as dominant of F
F7    F7    C7    A7      <-- A is dominant of D
Dm7   G7    C7    Dm7 G7  <-- initial Dm anticipates the coming of the dominant proper, G

Harmony can be further enriched by chromatic substitutions, again, the same basic idea as in classical harmony: finding chromatic neighbours for passing chords, etc. But I'm afraid I'm still trying to make my self at home with that part myself..

Answer 2

E pentatonic blues scale is

E-G-A-B-D

which as a harmonized scale in sevenths would be

    Em7 G7 Am7 B7 Ddim7

but blues being the forgivingly dissonant beast that it is would also accept, depending on the melody:

    E7 G7 A7 B7 D7

Depending on the context, you could also have success constructing chords out of whatever pentatonic notes take your fancy.

So instead of

 (E-G#-B) (A-C#-E) (B-D#-F#)

you could try

(G-B-D) (E-A-D) (D-G-A)

Don't overthink it. Avoid playing chord notes that are a tone or less away from the melody notes--unless you want to hear that tension--and have fun. There's a reason why the pentatonic scale is universal and that reason is simplicity.

Answer 3

I understand the concept of the blues scale and its blue notes flat 3rd flat 5th and flat 7th

Hmmm... I don't think it's quite that simple. IMO Blues playing is conceptually more about exploring ranges of the octave than being just a set of fixed notes like the major scale:

What's the difference between the tritone and the blue note?

https://music.stackexchange.com/a/31073/18896

my question is: What chords can you use to accompany the blues because I'm tired of just staying on the I IV V. In other words the major scale has a chord scale match up in the key of C: C, Dmin, Emin, Fmaj7, G7, Amin, Bminflat5. What would be the chords for the blues scale in C? C?, Eflat?, F? Fsharp?, G?, Bflat?

It sounds like you're in the mindset where you think you have to choose a scale, and then make both your chords and your melodies from the notes in that scale. You don't! That idea is often taught to beginners as it's easy to make something that 'works ok' if you stay within that, but it's not a "rule" of music.

Even 'standard' theory gives you plenty of routes out of that box - joseem has mentioned some of them. Speaking more informally, modern blues/pop/rock often seems to use a kind of 'hybrid' of the major, minor, and mixolydian scales, and adds a blues 'between the notes' sensibility, which leads to all kinds of possibilities of chord borrowing and bending things to 'make them fit'.

Robert Cray is an example of a blues musician who explores some less standard chord progressions; take a listen to the tracks Already Gone and Out Of Eden if you can find them. You might find them somewhat soul-tinged; indeed, soul music (and even motown) might be a good place to look for chord progressions that work with bluesy melodies.