Stop 4 of 5
The blues scale
The flat fifth: the note that changes everything.
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Stop 4 of 5
The flat fifth: the note that changes everything.
One single note. That's all that separates the minor pentatonic from the . But that note, the flat fifth, is so loaded that it can turn a correct phrase into a phrase with soul… or into a mess if you don't know where to put it. In this stop you learn to use the the way seasoned players do: in passing, with intent, and never moving in to live on it.
First the pentatonic you know, then the same with one extra note. Listen to what happens between D and E:
That new note, E♭, sounds odd on its own, almost wrong. But in motion it gives the scale a drag, a deliberate stumble that is pure blues. Hear it in a short lick:
The blues scale has six notes: the five of the minor pentatonic plus the flat fifth.
In box 1 the ♭5 appears in two comfortable places: on the 5th string, fret 6 and on the 3rd string, fret 8. Both sit one fret away from a note you already knew, so your fingers hardly have anything new to learn.
String 6, Fret 5: A2 · 1 · Root
From the root to the ♭5 is exactly six half steps: halfway through the octave, the . It is the most unstable interval in Western music; for centuries theorists treated it with great caution. In the blues that instability is a resource: the ♭5 pulls hard towards the 5th (a half step up) or the 4th (a half step down), and that pull is what we hear as "drag".
The golden rule of the ♭5: use it to go somewhere, not to arrive. Its two natural paths are chromatic:
Notice that the ♭5 almost always falls on the weak part of the beat (the second eighth) and lasts only briefly. Long notes and endings belong to the 4th, the 5th or the root.
Now hear what happens if you stay on it. Play the exercise over the drone: four beats of E♭, then the resolution to E.
The guitar's other "blue note" isn't written with a fret: it's made with the hand. Play C (the ♭3 of A) on the 3rd string, fret 5, or on the 1st string, fret 8, and push it just a tiny bit, about a quarter tone. The note ends up between C and C♯: neither minor nor major. That small gesture, sometimes called a curl, is probably the most characteristic sound of electric blues.
String 3, Fret 5: C4 · 1 · Scale tone
A minor third is 300 cents and a major third 400 (100 cents = one semitone). The quarter-tone bend leaves the note around 350 cents: a neutral third, which exists as an interval of its own in Middle Eastern music but not on the Western keyboard. Over an A7 chord, which contains C♯, the neutral third creates a deliberate friction that the ear reads as "blues". Printed tab marks it with "¼" above the number.
Two close relatives of the quarter tone that you can hear here: the half step from the 4th (D bent up to E♭, the ♭5 reached without a fret) and the half step from the ♭3 (C to C♯, the major/minor mix from the previous stop):
The ♭5 gets its name from the tonic, A. But a blues has three chords, and the same E♭ changes role depending on which one is sounding. Listen to each chord with the blue note on top:
| Chord | What E♭ is to the chord | How to use it |
|---|---|---|
| A7 | The ♭5: classic blues tension | In passing, with reasonable freedom |
| D7 | A half step above the root: very tense | Only fleetingly, quickly, on the way to D or E |
| E7 | A half step below the root, clashing with the ♭7 (D) | Only as an approach note into E |
That's why the blue note sounds best in the A7 bars and riskier over the IV and the V. It isn't a ban: plenty of solos use it everywhere. But the quicker and more "on the way" it is, the better it fits over any chord.
Two original licks that use everything above. The first, on the high strings, with a bend to the root and the ♭5 passing in a triplet:
The second, on the low strings, with the shuffle lilt written as triplets and the ♭5 climbing towards the 5th:
Just as the minor pentatonic has its blues scale, the major pentatonic has its own: add the ♭3 as a passing note between the 2nd and the 3rd (in A: A, B, C, C♯, E, F♯). It's the same ♭3 → 3 gesture you used when mixing, turned into a scale, and it sounds like country and happy blues.
Loop the "Paths of the ♭5" example with the metronome. Then invent your own paths in other octaves: the ♭5 is also on the 2nd string, fret 4, and on the 4th string, fret 1.
Goal: Play both chromatic paths (4–♭5–5 and 5–♭5–4) ten times in a row with the ♭5 on the weak part of the beat and no stray strings ringing.
Start by playing lick 1 in bars 1–2 and lick 2 in bars 7–8; improvise the rest. Before each phrase, decide which note you'll end on.
Goal: Two full choruses using at most one ♭5 per phrase and ending every phrase on A, E or C.
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