Classifying Cadences

Prose has full stops and commas, and music has degrees of closure in the same way.

Is this a definite ending, or just a place to breathe? What decides the difference is the cadence, and a cadence is determined by the last two chords of a phrase.

The three functions from the previous lesson now take concrete shape.

Authentic cadence — the full stop

The strongest ending available is V → I, the authentic cadence.

The leading tone and tritone carried by the dominant discharge into the tonic all at once. This is the full stop.

Authentic cadences come in degrees of strength. One that meets all three of the following is a perfect authentic cadence.

1. V is in root position
2. I is in root position
3. the soprano ends on the tonic

Fail any one and it becomes an imperfect authentic cadence, with a weaker sense of arrival. The third condition carries the most weight in practice. Given the same V–I, whether the top voice lands on the tonic makes an audible difference to how settled the ending feels.

Perfect against imperfect

▶Perfect authentic▶Imperfect authentic

Check: Both are G to C. The only difference is where the soprano ends. In the first it arrives on the tonic C and nothing more could follow. In the second it ends on the third, E, which leaves an opening. Only the first can end a piece.

soprano B→C, landing on the tonic

Check

A V–I cadence occurs, but V is in first inversion with the leading tone in the bass. Is this a perfect authentic cadence?

Imperfect authentic cadencePlagal cadenceHalf cadencePerfect authentic cadence

Check answer

Plagal cadence — the quiet close

IV → I is the plagal cadence.

It moves from subdominant directly to tonic. Containing no leading tone, it lacks the sharp resolution of an authentic cadence and closes gently instead.

It is the progression sung on “amen” at the end of hymns, which is why it is also known as the amen cadence.

A common way of writing an ending is to follow an authentic cadence with a plagal one, settling the close one further degree.

Half cadence — pausing for breath

Ending on V is a half cadence.

This is not so much an ending as an ending that announces it is not over. Stopping while still holding the dominant’s tension makes the existence of a continuation obvious. It is the comma.

In an eight-measure phrase, the first four measures typically end with a half cadence and the second four with an authentic cadence. That pairing is the basic classical period, treated in detail in Unit 7.

Half cadence beside authentic cadence

▶Half cadence (stopping on V)▶Continuing to an authentic cadence

Check: The first stops on V. It hangs, and you find yourself waiting. The second opens identically and continues home to I. Same three chords on the way through — the presence or absence of one final chord is what divides a question from an answer.

I – IV – V. Awaiting a continuation

Deceptive cadence — the swerve that buys time

V → vi is the deceptive cadence (V → VI in minor).

Arriving on the dominant leads the ear to expect the tonic, and then the music veers to vi, the tonic’s substitute. As the previous lesson showed, vi shares two notes with I, C and E, which produces a state of being similar but not the same — suspended rather than resolved.

The detail worth noticing is that the leading tone does resolve to C as promised. Only the bass breaks its word; the upper voices behave exactly as expected. That is why it registers as a feint rather than an error.

Deceptive cadences are for when you do not want the piece to end yet. Inserting one where an ending was due lets you build the music back up one more time.

Phrygian cadence — a half step down in the bass

Minor keys have a cadence of their own: first-inversion iv moving to V, called the Phrygian cadence.

In C minor, iv is Fm. In first inversion its bass is A♭, and moving from there to V on G makes the bass descend a half step, A♭ to G.

Because it ends on the dominant it is a species of half cadence, but the distinctive half-step bass motion has earned it a separate name. Baroque slow movements routinely end this way and run straight on into the next movement.

The cadential 6-4 — a tonic chord standing in front of the dominant

One more formula, which turns up constantly just before a cadence.

Unit 3 established that second inversion is unstable because it puts a perfect 4th above the bass. This formula puts that instability to work deliberately.

The thing to look at is that the bass holds G across both chords. It remains on the dominant while only the upper voices move to form V.

Which means this I64 is not functioning as a tonic chord at all. It is working as an ornament that delays the arrival of the dominant. So although it is written I64, functionally it is part of the dominant.

It is the figure placed just before the soloist’s cadenza in a concerto, which is where its name comes from.

Check

In a cadential 6-4, what does the bass do?

Leaps from tonic to dominantStays on the dominantDescends by half stepsMoves from leading tone to tonic

Check answer

All five together

The five cadences in sequence

▶Authentic▶Plagal▶Half▶Deceptive▶Phrygian

Check: Each excerpt is just the final two chords. One and two can end a piece; three waits for more; four is a feint; five is the minor-key formula with the bass falling a half step. Play through a few times and try ranking them by how finished they sound.

V→I. The strongest

▶ Run twenty questions on the cadence trainer Start with the basic three by ear. Once those are comfortable, switch to all five and the deceptive and Phrygian cadences enter the mix Cadence Trainer →

Knowing the cadences means you can listen to a piece and register in real time where it has broken and where it is still running. The next lesson takes up how quickly the chords change. The same progression at a different rate of change is a different piece of music.