Do you have the blues? If not, you might be missing a wonderful musical opportunity. Blues scales, blue notes, and blues progressions are common to jazz, country, gospel, funk, R&B, folk, and other styles.
Learning to play blues—at least those elements of blues shared by other genres—is a great way to speak the universal language of music. For instance, when unfamiliar musicians get together to jam, they often get musically acquainted by playing a common 12-bar blues progression, in a typical blues key such as D or G.
Learning blues scales can also set an intermediate musician on the road to learning how to improvise. In its most basic form, jazz improvisation spices up chords and riffs by adding in colorful blue notes.
In terms of music theory, the blues scale is related to two other scales—the minor pentatonic scale and the natural minor scale (the chart shows how these scales are related). Both these scales use a flatted third (minor third or iii) and a flatted seventh (minor seventh or vii).
The note that really sets the blues scale apart from other scales is its flatted fifth (diminished fifth, tritone, or v), which is Gb in the key of C, Ab in D, and Db in G. The flatted third, flatted fifth, and flatted seventh are often called “blue notes.”
Blue notes are said to have arisen in American music genres (specifically blues and jazz) because they approximate notes common in African music scales brought over to the US, along with the rhythms, call-and-response, and other musical structures heard in these forms.
The pentatonic scale on which the Western blues scale is based, however, is borrowed from European folk music, a tradition that African music combined with to create a hybrid, specifically American music.
Blues scales and blue notes have a characteristically “sad” tone, and the relationship of blues scales to common minor scales helps explain that. But there’s also tension created in blue notes that adds an interesting flavor to the blues. Musically speaking, blue notes are “unstable” and “tense,” and our ears expect the notes to be resolved and the tension released.
One way blue notes are used in music is as grace notes to major chords. For instance, pianists can add an interesting dimension to a regular C maj chord (C, E, G) by lightly playing F#/Gb before it. The illustration (FIG. 3) shows how this grace note/chord combination looks on a sheet of music.
Guitarists get the same grace note effect by either bending notes or playing with a bottleneck or slide. Both techniques offer ways to gracefully add in flats in the same way that a pianist might use grace notes. Slide blues typically requires a guitar to be retuned to a major open chord, such as D or G. Bending strings upward to create a sharp or flat can be done on any guitar. Masters of this technique include B.B. King and Eric Clapton.
If you’ve learned blues scales and notes, the next step is to learn the structure of the 12-bar blues progression. This will be very useful if you ever play an open jam. Plus, this basic structure is a good one around which to improvise.
A typical 12-bar blues progression uses a key’s I, IV, and V chords in the following pattern: I x 4, IV x 2, I x 2, V x 1, IV x 1, I x 2. In D, you’d play chords D, G, and A; in G, you’d play G, C, and D.
There is plenty of room to play around in this pattern, which is where the blue notes come in. One way to improvise is to play a blues progression and add in blue notes to create interesting moments of tension and release.
The relationship between the notes and chords of a blues progression and the blue notes that accompany them in the blues scale is unusual. The blue notes don’t really fit smoothly with the progression’s notes and chords, although this dissonance is something that our ears enjoy nonetheless.
How the flatted fifth sounds gives a clue to how the blues scale is used. The flatted fifth is an unstable note and begs to be resolved. Interestingly, either resolving up to a blues progression’s perfect fifth (V) or down to its perfect fourth (IV) sounds good.