The cycle, the circle of 5ths, the circle of 4ths—these are terms for harmonic movement through the 12 notes of our musical system. Confusion abounds when musicians arbitrarily say a progression moves through the “cycle,” or goes “around the circle,” without specifying which cycle or in which direction (4ths or 5ths) around the circle.
Countless songs use root movements in the circle of 4ths and the circle of 5ths. Once you understand the concept, you’ll always know what key you’re in and understand the theory behind the key signature. This month, let’s clear up the mystery surrounding the cycle, the circle, or whatever you want to call this amazing bit of musical mathematics. To avoid dazed indifference taking hold, we’re not going to look at a diagram of the circle (that’s coming next month). Instead, let’s examine major and minor scales, and their key signatures.
Example 1 shows all major and minor scales, beginning with C major and moving through the circle of 4ths. We call this the circle of 4ths because every new key begins the interval of a 4th up from the previous key (Ex. 2). In the progression through the circle of 4ths, a flat is added to each subsequent key signature. Study the chart below and play through Ex. 1, paying attention to the intervallic distance between each starting note, and the additional accidental—in this case, another flat.
CIRCLE OF 4THSMajor (minor) key# of accidentalsAccidentals in key signatureC major (A minor) 0 — F major (D minor) 1 BbBb major (G minor) 2 Bb, EbEb major (C minor) 3 Bb, Eb, AbAb major (F minor) 4 Bb, Eb, Ab, DbDb major (Bb minor) 5 Bb, Eb, Ab, Db, GbGb major (Eb minor) 6 Bb, Eb, Ab, Db, Gb, CbCb major (Ab minor) 7 Bb, Eb, Ab, Db, Gb, Cb, Fb
Example 3 shows all of the major and minor scales, beginning with C major and moving through the circle of 5ths. We call this the circle of 5ths because every new key begins the interval of a 5th up from the previous key (Ex. 4). With each new key, a sharp is added to the key signature.
CIRCLE OF 5THSMajor (minor) key# of accidentalsAccidentals in key signatureC major (A minor)
G major (E minor)
D major (B minor)
A major (F# minor)
F#, C#, G#
E major (C# minor)
F#, C#, G#, D#
B major (G# minor)
F#, C#, G#, D#, A#
F# major (D# minor)
F#, C#, G#, D#, A#, E#
C# major (A# minor)
F#, C#, G#, D#, A#, E#, B#
Notice that three pairs of sharp and flat key signatures contain enharmonic equivalents—the scales are notated differently, but they share the exact same pitches. They are: B major and Cb major, F# major and Gb major, C# major and Db major. Look at the charts above, and study the notes in the three pairs of scales. Now play them on the bass. Notice how these scales are written differently, even though they sound the same.
The key of B major (G# minor) shares the same pitches as Cb major (Ab minor), even though the pitches are notated differently. The pitches in the keys of F# major (D# minor) and Gb major (Eb minor) sound the same but are notated differently. The notes of the scales C# major (A# minor) and Db major (Bb minor) are also enharmonic equivalents—they sound the same, but they, too, are spelled differently.
Next month, we’ll study the musical mandala, the flying saucer, the mothership of our musical system: a graphic diagram of the circle of 4ths and 5ths. Until then, concentrate—you’ve got this!