Blue notes and other microtones

Update: here’s a deeper and better-informed explanation of blue notes.

Blue notes are a big part of what makes the blues sound like the blues. Most other American vernacular music uses blue notes too: jazz, funk, rock, country, gospel, folk and so on. In the video below, John Lee Hooker hits a blue note in just about every single guitar phrase.

For such a foundational element of America’s music, there’s a surprising amount of confusion as to what a blue note is exactly. So allow me to clear it up: a blue note is a microtonal pitch in between a note from the blues scale and a neighboring note from the major scale.

Here’s a guide to the blue notes in the key of C.

• C major scale: C, D, E, F, G, A, B
• C blues scale: C, E-flat, F, F-sharp, G, B-flat
• C major plus C blues: C, D, E-flat, E, F, F-sharp, G, A, B-flat, B

There are three notes from the blues scale not found in the major scale, in bold above:

• E-flat — the flat third
• F-sharp — the sharp fourth
• B-flat — the flat seventh

The flat third and seventh give the blues scale its tragic minor-key feeling. The very dissonant sharp fourth makes the blues unsettling and dark. Some people commonly refer to these non-major scale notes as blue notes. That’s not right — they’re blues scale notes that still fall on the piano keys. The blue notes fall between the piano keys, between each blues scale note and its closest major-scale neighbor.

In the key of C, there are blue notes between:

• D and E-flat
• E-flat and E
• F and F-sharp
• F-sharp and G
• A and B-flat
• B-flat and B

To play a blue note on guitar, like John Lee Hooker does, you bend the strings, making them go sharp.

If you’re playing slide guitar, you just move slightly above or below a given fret. On trumpet, sax or harmonica, you can bend the notes by overblowing. On a synth, you use the pitch bend control, like Herbie Hancock does in “Rockit.” At about 2:50 in he kicks off his solo with the blue note between the sharp fourth and fifth.

Herbie uses blue notes throughout his synth solo in “Chameleon” — listen around 5:00 – 5:30.

On trombone, fretless string instruments like violin, and the voice, pitch is continuous, so playing blue notes is as easy as playing “correct” piano key notes. You can’t play blue notes on the piano, but you can approximate them by playing adjacent keys simultaneously, for example F and F-sharp.

The blue notes I listed are the most commonly used ones, but any microtone can find its way into the blues. Harmonica players sometimes use a slightly flattened C, D or A in the key of C. Guitarists will bend any note so that it’s slightly sharp when playing very emotionally and emphatically.

The western tuning system is cool and versatile and full of intriguing symmetries, but it gets oppressive after a while. We’re taught that pitches from outside our system are “out of tune” or “wrong.” If you’re intending to play the standard pitches and you miss, that does usually sound bad. But when you play between the piano keys on purpose in musically logical places, microtones can be the most beautiful sound in the world. Blue notes enrich the western tuning system with glimpses of the infinite possibility of the underlying continuous pitch spectrum.

Other world cultures routinely use subdivisions of the octave much finer than the western half-step. Indian and Arabic scales use quarter tones. Klezmer clarinetists bend and stretch pitches like silly putty. Some avant-garde western western composers use their own idiosyncratic microtonal systems to write music that sounds like it’s playing on a warped records. That gets to be a little too much pitch freedom for my tastes. I prefer my microtones against a nice steady backdrop of western equal temperament, they jump out more that way.