The minor pentatonic blues scale is commonly referred to as “the blues scale” because it is a very popular scale for blues guitar players and contains all of the blue notes, as explained below.
However, this is not the only scale used by blues guitarists.
Blues guitarists use a variety of scales, including combinations of scales, as well as approaches to using them that differ from traditional music.
Using a minor third interval over a major or seventh chord, for example, is something you won’t hear in Classical music but might hear in Rock and Pop because they’re influenced by the blues.
However, using a minor third interval over a major or a seventh chord is a common blues practice. In fact, some of the blues guitar scales we’ll look at below are a hybrid of major and minor to meet the needs of blues musicians.
Blue notes
Blue notes can mean different things to different people. The most common are:
1. Notes that only exist between two of the chromatic scale’s 12 notes. For instance, a note that is higher in pitch than A but lower than A#.
These notes are achieved on a guitar by using micro bends. That is, instead of reaching the note A#, bend the note A but stop somewhere in the middle.
2. A note that is a flat 3rd, a flat 5th, or a flat 7th of a scale degree of a diatonic major scale. (For example, the notes of C major are C, D, E, F, G, A, and B, so the blue notes when playing over C major are Eb, Gb, and Bb.)
3. The flat 3rd, flat 5th, and flat 7th are chromatic notes, which means they are not in key. Some people consider all chromatic notes used in blues to be blue notes.
The reason for the confusion over what a blue note is has to do with the evolution of the blues, which was influenced (as well as influenced) by racial issues. (For example, some argue that the second definition of a blue note provided above is an attempt by white musicologists to understand black blues musicians, but it does not accurately reflect how the musicians were thinking.)
This is how the term “blue note” will be used in this context:
1. The blue note is a flat 3rd, a flat 5th, and a flat 7th of a major scale degree of the same tonic in the first six scales for blues guitar.
2. In the final guitar scale for blues in this lesson, we’ll look at a different way of thinking about blues that makes use of a broader definition of the term “blue note.”
Now that we’ve defined what a blue note is in this lesson, let’s look at the seven commonly used scales by blues guitarists.
Guitar scales for blues
- Minor blues scale, aka “the blues scale”
This lesson delves deeply into the most popular blues scale, but because it is so widely used, it deserves a mention here as well.
The minor blues scale is popular because it contains all three blue notes (and because it’s easy to use over a blues progression).
The notes of the A major scale are A, B, C#, D, E, F#, and G#.
The notes in the A minor blues scale are: A, C, D, Eb, E, and G. The blue notes, the flattened third (C), fifth (Eb), and seventh (G), are all present in the minor blues scale.
Now, one may ask: If we’re in the tonality of A major, how can we use the minor blues scale? Wouldn’t the blue notes clash with the chords?
The answer is that yes they clash, but they clash in a way that blues musicians have made sound musical. Had Bach been throwing blue notes in his fugues, the conductor would have been pelted with tomatoes. But when BB King uses blue notes, he’s putting “bluesness” in the Blues and the audience cheers.
Though blues is tonal music, in that all notes and chords lead to the tonic note (for example, A in A major), it follows different rules than traditional Western tonality. In most blues, for example, the tonic chord is I7 (A7 in A major). The dominant chord is never used as a tonic in traditional Western harmony, which is usually a major triad (A), sometimes a minor triad (Am).
The A minor blues scale is used to create all of the notes in the following blues guitar lick. The blue note in the lick is bent up to from the fourth note.
- Major pentatonic scale
Because all of the notes in the major pentatonic scale are derived from the major scale, there are no blue notes in it.
It is still used in blues, but it is less beginner-friendly than the minor pentatonic or minor blues scale.
When playing over a I7 IV7 V7 chord progression (most blues), you can continue to use the same minor blues scale as the progression moves to the IV (D7) and V chords (E7).
But the major pentatonic will only sound right if the scale is changed with each chord change. That is, the A major pentatonic is used over the I7 chord, the D major pentatonic is used over the IV7 chord, and the E major pentatonic is used over the V7 chord.
The A major pentatonic pattern is as follows.
All the notes in the following lick are derived from the A major pentatonic scale.
- Major blues scale
Just like the minor blues scale is the minor pentatonic with an added blue note (the flat 5th), the major blues scale is the major pentatonic notes plus a flat 3rd.
The notes of the major blues scale are as follows: A, B, C, C#, E, F#. They are the same notes as the A major pentatonic except for the addition of the note C.
This note makes the major blues scale sound bluesier than the major pentatonic.
The following lick uses only notes from the major blues scale.
- Major and minor pentatonic superimposed
In traditional music that is not blues-influenced, it is clear if the composer or improviser is in a major or a minor key (for example, if he is in A major or A minor). He may borrow notes from the major or minor key, he may modulate (change key), but he is clearly in one key at any specific point in the song.
This clear distinction between major and minor tonality is blurred in blues.
Thus, by superimposing the minor pentatonic and major pentatonic scales over each other, a convenient hybrid scale for blues guitar is created.
The next lick makes use of some of the chromatic possibilities offered by this scale.
- Dorian mode
Since I’m primarily a Metal guitarist, I tend to favor the natural and harmonic minor scales, as well as the Phrygian mode.
They have a sadder, more aggressive sound to me than the Dorian mode, which has the same notes as the natural minor but with a sharpened sixth (A natural minor = A, B, C, D, E, F, G; A Dorian = A, B, C, D, E, F#, G.
Dorian still sounds minor and sad, but the sharpened sixth makes it sound brighter and happier, making it among the more popular scales for blues guitar playing.
The scale pattern for the A Dorian mode is as follows:
The following lick captures the flavor of the Dorian mode by making repeated use of the sharpened sixth (F#) in the second bar.
- Mixolydian mode
While Dorian is the minor mode of choice for many blues guitarists, the Mixoldydian is the major mode blues players tend to choose.
The notes are the same as in the major scale, except for the flat 7th (G instead of G#), which is a blue note.
The A Mixolydian scale pattern is shown below.
The next lick is in A Mixolydian and begins with the flat 7 degree of the scale (G) sliding into the tonic (A).
- Microtonal blues scales
All of the scales mentioned above are legitimate tools for playing the blues.
Is this, however, how original blues musicians thought about scales when improvising?
This microtonal blues scale lesson series proposes the theory that blues guitarists may have been thinking of intervals like “the majorish third” and concepts like “pitch shading” when soloing or improvising.
If you’re just starting out and want to play some blues, these scales might not be for you. However, if you want to study the blues in depth, I believe they can provide you with a clear perspective of a way to approach the blues that you can use in your playing or choose not to use but still get the value of perspective if you don’t.
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