Cadence – a two-chord harmonic gesture that ends a phrase of music.
Classical-period composers spend a lot of time setting up, stating, confirming, and avoiding cadences. Multiple recent theories of classical form focus on cadences to define the structural layouts of Hadyn, Mozart, and Beethoven.
This page is mostly about cadences in that period of music, as cadences become fewer and farther between in Romantic music, as harmony becomes a secondary element of form in 20th century classical music, and as these labels are more difficult to ascribe to rock/pop. Cadences exist in all these repertoires, but not in such an easy to list format.
Authentic Cadence (AC)
There are two kinds of authentic cadence: perfect and imperfect.
Perfect Authentic Cadence (PAC)
PAC – Root Position V to Root Position I with Do as the last note in the melody. The most conclusive cadence.
Imperfect Authentic Cadence (IAC)
IAC – Any other AC that is missing an element from the PAC. Such as: inversions, Mi or Sol as last note in the melody, vii°6 instead of V. Somewhat conclusive.
Half Cadences (HC)
HC – Any cadence ending on V. Usually preceded by I or some sort of P. Inconclusive, requires the music to continue.
There are two kinds of HC that are more specific.
Phrygian Half Cadence (PHC)
PHC – A HC that goes iv6 to V. Le to Sol in the bass.
Tonicized Half Cadence (THC)
THC- A HC that precedes V with a secondary dominant. Fi to Sol.
Plagal Cadence (PC)
PC – A cadence that goes IV to I. in classical music, this gesture can only occur after a final PAC, like an “Amen” at the end of a hymn.
Deceptive Cadence (DC)
DC – A cadence that avoids an AC by replacing I with a vi. V–vi. In classical music, this gesture makes the phrase continue or rebegin and try to find an AC.
Part Writing Exception! When part writing vi (VI) following V, you double the third in vi chord (Do).
- Listen to the music and mark where you think you hear cadences. All of this stuff on this page is about hearing something, and then searching for it in the score.
- Followed by a rest or other kind of obvious visual or aural pause.
- The next moment is the return of a previous melody or an another obvious melodic beginning.
- A sudden shift of harmonic rhythm. That is, the length of the chords suddenly gets shorter or longer.
- Every 2, 4, or 8 measures. Not guaranteed, but classical composers were interested in playing off of this sense of phrase balance.
- The end of a melodic phrase that coicides with a harmonic shift. Last chord is usually V or I.
- In vocal music, where the words have a punctuation mark or an obvious pause.
- Look for the Bass to go Sol-Do or Do Sol.
- Authentic cadences are usually all in root position. The new theories I mentioned at the top say that IACs that have inversions are not actually cadences.