A cycle in a chord progression occurs when the root motion of one chord to another follows a fixed interval – in thirds, fourths, fifths, etc. As an example, you could start on C major and then use one of the cycles until you reach the initial chord. Or, which is more often the case, you could back-cycle the last four chords using any given cycle until you reach the target chord, like a cadence. The chord cycle extension depends on your aesthetic goal.
- Generally speaking, a chord progression that is based on the cycle of fifths is considered strong because the succession of cadences gives an impression of the inevitable return to the tonic of the piece
Descending cycle of fifths from Am – Dm to G
- The cycle of thirds, sounds smoother because of the voice-leading aspect, where there are at least two common notes between chords
Ascending cycle of thirds from Dm – F to Am
- Finally, the cycle of seconds is probably the most moderate in the way it moves and approaches a target chord, if that is your intent
Ascending cycle of seconds from F – G to Am
The type of chord cycle usually states the importance of the musical phrase or cadence but, as always, this also depends on your aesthetic discernment.
The interval cycle of a chord progression, and the chords themselves, may belong to the harmonic field or tonality you are working on. For instance, in a cycle of thirds based on the C major tonality you will encounter the respective minor or major third intervals . And the same can be said regarding the chord’s quality – major, minor, diminished or augmented, according to that tonality or specific scale harmonization; as is the case in the examples above.
But this doesn’t mean that you are stuck with using only those chords or having cycles that have to respect the intervals present in that tonality. A cyclic chord progression may indeed be a tonal sequence while respecting the pitch intervals and chord quality present in that tonality, as seen thus far.
But it can be also based on a real sequence where you can decide that you wish to make a chord progression based solely on a major thirds cycle, for example. Eventually, because you will end up using pitches that are chromatic to that tonality, you may decide to maintain the quality of the chords – all major, minor 9th, maj7, or any other:
Real chord sequence based on an ascending cycle of major thirds with melody from C major tonality
If you wish to take interval cycles a step further, you can also experiment with superimposed chords and compose a chord progression where both chords move in different cycles, using real or tonal sequences, or even creating melodies based on interval cycles. As with other tools, it will all depend on your creativity while manipulating musical materials and concepts.
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