Cadences and harmonic rhythm

Music without cadences is like a text without punctuation: you run out of breath and lose your way. Cadences are music's commas, semicolons and full stops. And harmonic rhythm — the speed at which chords change — is its breathing. Master these two tools and your music will speak with a clear diction.

1. The four essential cadences

2. Question and answer: half cadence then perfect cadence

This is the most common pairing in all of tonal music. The first phrase stops on V (we wait for more), the second restates the same opening and concludes on I. Listen to how bar 4 "asks a question" and bar 8 "answers".

M:4/4
L:1/4
Q:1/4=84
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"E2 G2 | "F"A2 "C"G2 | "Dm"F2 "C"E2 | "G"D4 | "C"E2 G2 | "F"A2 "C"G2 | "G7"F2 D2 | "C"C4 |]
[V:LH] [C,E,G,]4 | [F,A,C]2 [E,G,C]2 | [D,F,A,]2 [C,E,G,]2 | [G,,G,B,]4 | [C,E,G,]4 | [F,A,C]2 [E,G,C]2 | [G,,F,B,]4 | [C,E,G,]4 |]

Notice a key detail: in the perfect cadence of bar 7, the melody falls F → D → C, and the G7 chord contains the leading tone B, which rises to C. The more the melody ends on the tonic (C), the stronger the close. If it ends on E or G, the cadence is still perfect but sounds less final.

3. Deceptive and plagal cadences

The deceptive cadence is a small coup de théâtre: after G7 the ear expects C, and gets A minor instead. The phrase is forced to carry on. Here, after the surprise in bar 3, we set off again and conclude… then add a plagal cadence (F → C) like a final "Amen".

M:4/4
L:1/4
Q:1/4=76
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"E2 G2 | "G7"F2 D2 | "Am"C4 | "Dm"F2 A2 | "G7"G2 B,2 | "C"C4 | "F"C4 | "C"C4 |]
[V:LH] [C,E,G,]4 | [G,,F,B,]4 | [A,,C,E,]4 | [D,F,A,]4 | [G,,F,B,]4 | [C,E,G,]4 | [F,,C,A,]4 | [C,E,G,]4 |]

4. Harmonic rhythm: how chords breathe

Harmonic rhythm is how often the chords change. One chord per bar feels calm and spacious; two chords per bar build momentum. Listen to the same melody: first one chord per bar (bars 1–4), then two chords per bar (bars 5–8).

M:4/4
L:1/4
Q:1/4=80
K:C
%%staves {RH LH}
V:RH clef=treble
V:LH clef=bass
[V:RH] "C"E2 C2 | "Dm"F2 D2 | "C"E2 C2 | "G"D4 | "C"E2 "Am"C2 | "Dm"F2 "G"D2 | "C"E2 "Am"C2 | "G7"D2 "C"C2 |]
[V:LH] [C,E,G,]4 | [D,F,A,]4 | [C,E,G,]4 | [B,,D,G,]4 | [C,E,G,]2 [A,,C,E,]2 | [D,F,A,]2 [B,,D,G,]2 | [C,E,G,]2 [A,,C,E,]2 | [B,,D,F,]2 [C,E,G,]2 |]

The second version feels more urgent, more "active", even though the melody is nearly identical. It's a powerful lever: many composers speed up the harmonic rhythm as the cadence approaches (say one chord per bar, then two, then the cadence), which creates a natural push towards the close.

5. Where to put cadences

• Usually every 4 bars: half cadence in bar 4, perfect cadence in bar 8.
• The cadence lands on a strong beat, preferably the downbeat of the bar.
• Save the strongest perfect cadence (melody on the tonic, bass G → C) for the very end of the piece; intermediate endings can be lighter.

Your workshop

1. In the piano roll, write a 4-bar phrase in C major that ends on a G chord (half cadence).
2. Copy it into bars 5–8 and change only bars 7–8 so they end G7 → C (perfect cadence), with the melody on C.
3. Then add 2 bars: replace the final cadence with a deceptive one (G7 → A minor) and conclude again with F → G → C.
4. Vary the harmonic rhythm: one chord per bar at the start, two chords per bar in the two bars before the cadence.
5. Explore other progressions in chord progressions to find ways into the cadence (ii → V → I, for instance).
6. Self-check: play your phrase to someone and stop at bar 4: do they want to hear what comes next? Stop at the end: do they feel it's over?