Identifying sequences

The final topic in pop aural skills is harmonic sequences, strings of chords whose roots move in a predictable interval pattern. Sequences are common in European classical music. Listen to Bach’s Chaconne from the D Minor Violin Partita or Contrapunctus VIII from The Art of Fugue for a million examples. Sequences are also pretty common in jazz. They are not so common in pop. But when people do use them, it can sound like a fun harmonic adventure. 

Circle of fifths sequences

Many sequences are organized around the circle of fifths, so let’s start there. The basic idea is simple. Say you want to write a sequence in the key of C major. You find your chord roots by starting on C and moving through the key in counterclockwise circle of fifths order, like so: C, F, B, E, A, D, G, C. 

Note that these steps are not all perfect fifths! When you get to F, you aren’t going to continue on to B-flat; instead, you are going to the next counterclockwise note on the circle that’s within the key, and that means skipping all the way around to B a tritone away.

Now that you have your chord roots, all you have to do is add chords on top that are diatonic to the key. That gives you C, F, Bdim, Em, Am, Dm, G, C. This sounds… fine. It’s logical, it makes sense, but it’s lacking in color and drama. You can add color by using seventh chords rather than triads: Cmaj7, Fmaj7, Bø7, Em7, Am7, Dm7, G7, Cmaj7. And you can add drama by replacing some or all of the minor chords with secondary dominants. It’s very common to use E7 instead of Em7 to make Am feel like the temporary tonic in the key of A minor. You can also get a jazzier feel by using A7 instead of Am7 and D7 instead of G7.

This same method works for minor keys too. To create a sequence in A minor, use the same exact chords you did for C major, but start and end on Am rather than C. Minor-key sequences are quite a bit more common in jazz and pop than major-key ones for some reason.

Here’s an interactive Noteflight explainer of all this.

There are infinite variations on the basic circle of fifths sequence. You don’t have to start or end on the tonic, you don’t have to do the entire circle, and you don’t have to space the chords out evenly in musical time.

The Beatles’ “You Never Give Me Your Money” uses an A minor circle of fifths sequence in its first section. Note that the harmonic rhythm isn’t even; there are two chords in the sixth measure.

| Am7 | Dm7    | G7 | C  |
| F   | Bø7 E7 | Am | Am |

Gloria Gaynor’s “I Will Survive” uses the exact same chord progression, just timed differently.

| Am    | Dm  | G7     | Cmaj7 |
| Fmaj7 | Bø7 | E7sus4 | E7    |

Déaglin Ó Faoláin pointed out to me that “Mr Crowley” by Ozzy Osbourne also uses this same progression. Hilarious!

The first half of “Autumn Leaves” is a wrinkle on the minor key sequence, starting on scale degree four rather than the tonic. The iconic Cannonball Adderley recording is in G minor. The tune proper starts at 0:52 after a long and laconic intro groove. The chord roots move from C to G around the circle. 

| Cm7 | F7 | Bbmaj7 | Ebmaj7 |
| Aø7 | D7 | Gm     | Gm     |

Circle of fifths movement can also be the result of chains of secondary dominants, as in the verses of “Spinning Wheel” by Blood, Sweat & Tears. The main idea here is a loop of E7, A7, D7 and G. The G chord is I, the D7 chord is V, the A7 is V/V, and the E7 is V/V/V.

It’s less common for chord roots to do extended clockwise movement around the circle, but it does happen in rock. You can hear chains of clockwise circle movement in “Hey Joe” by Jimi Hendrix and “The Time Warp” from The Rocky Horror Picture Show.

Descending third sequences

Sequences don’t have to go around the circle of fifths; they can move by other intervals too. The most common alternative is to move in descending thirds. The granddaddy of all descending thirds sequences is Pachelbel’s Canon.

| D  A  Bm  F#m | G  D  G  A |

Think about these chords in pairs. D and A are a fifth apart, as are Bm and F#m, and G and D. If you think of each pair as a single entity, then the progression descends in diatonic thirds: D to B is a minor third, and B to G is a major third. Pachelbel could have continued the sequence by making the last pair Em to Bm, but instead he breaks it to create a cadence that leads back to the beginning of the loop.

Notice that if you invert some of the chords, you can use a descending D major scale for a bassline:

| D  A/C#  Bm  F#m/A | G  D/F#  G  A |

The Pachelbel changes are irresistible to unimaginative pop songwriters. I find all of these songs annoying, but “Raining Tacos” is at least funny.

“Hotel California” by the Eagles has a similar pairwise organization, but the pairs descend by whole steps rather than thirds. (The pattern breaks for the last two bars.)

| Bm | F#7 | A  | E   |
| G  | D   | Em | F#7 |

My aural skills students are worried that they can’t just effortlessly identify long, complex chord sequences by hearing them. But no one expects them to be able to do that immediately or effortlessly. The important thing is to be able to identify a general “circle of fifths-ness” or “descending thirds-ness”. If you can sense that chord roots are moving around the circle of fifths, you still have to identify those chords one at a time, but knowing about the pattern narrows the search space down significantly.

I chose the examples here for their clarity and tidiness. Most sequence-based songs mix in other kinds of chord movements. My recommendation is just to learn as many songs as you can, in as many different keys as you can, and the patterns will become more apparent and intuitive over time. This won’t get you through a one-semester class, but over your lifetime as a musician, it works great.