Harmonic rhythm is how often chords change in a passage of music, and is measured in note values. For example, if chords change every half-note, we say “the harmonic rhythm is a half-note.” Or, if the harmony changes every quarter note, we say “the harmonic rhythm is a quarter-note.” Sometimes the harmonic rhythm is a combination of note values that change at a regular rhythm, such as a half-note followed by a quarter-note:
Introduction to Cadences
We have described tonal harmony as a hierarchy of pitches and chords where one pitch or chord has prominence over all the others. This tone or chord, as we learned in this music theory lesson, is the tonic scale degree. We might say that the tonic is the goal in a piece of tonal music. In order to reach that goal, the music progresses towards it (hence, the term harmonic progression).
Harmonic progressions set up expectations in our ears, expectations that are fulfilled only when the tonic chord is reached. Some of the greatest music ever written plays on this idea by setting up expectations, then denying them, creating tension in the music. This tension gives way to relaxation when the tonic chord is finally reached. When music comes to a point of relaxation or repose, it is called a cadence.
All of the elements of music (melody, harmony, rhythm, dynamics, timbre) contribute to cadence, but traditionally, we classify cadences according to their harmonic content. Most of the time, cadences are easy to identify because of the sense of culmination they create in the music. For example, cadences are often accompanied by longer note values, a slowing of the tempo, and a change in the harmonic rhythm.
But not all cadences end with the tonic chord. There are many cadences of varying degrees of strength. Some cadences sound complete, that is, the music comes to a rest, and we don’t hear a need for the music to continue. These types of cadences are called conclusive cadences. Then there are cadences that do not sound complete, that is, the music sounds like it needs to continue. We call these types of cadences inconclusive cadences.
For the remainder of this lesson we’ll show you how to identify and label the various cadence types. In future lessons, we’ll see how these cadences work in actual music. Use this lesson as a reference and to help you memorize the cadences.
The authentic cadence is the most fundamental and final sounding of all cadences. It consists of a dominant triad or dominant seventh chord followed by the tonic triad (V-I, V7-I). There are two types of authentic cadences: the Perfect Authentic Cadence (PAC), and the Imperfect Authentic Cadence (IAC).
Perfect Authentic Cadence (PAC)
The perfect authentic cadence has specific requirments:
- It is a V-I or V7-I progression.
- Both chords, V and I, must be in root position.
- Scale degree one () must be in the soprano of the I chord.
Here are two examples of a perfect authentic cadence.
Imperfect Authentic Cadence (IAC)
Any authentic cadence (V-I or V7-I) that does not meet the requirements above, is an imperfect authentic cadence. In the first example, scale degree one () is not in the soprano. In the second example, the V chord is not in root position:
The Plagal Cadence, a IV moving to a I, often is called the “Amen” cadence because of its frequent occurrence at the end of hymns:
Half Cadence (HC)
Any cadence that ends with a V chord is a half cadence:
Phrygian Half Cadence (PHC)
A Phrygian half cadence is a iv6-V progression and occurs only in a minor mode. It is characterized by a descending half-step in the bass. The soprano usually contains scale degree 4 moving to 5, but this is not a requirement.
When we hear a dominant chord near the end of a musical phrase, we are expecting a resolution to the tonic chord. The deceptive cadence denies this expectation. The most common deceptive cadence is the dominant chord moving to a vi. A variant of the V-vi, and a favorite of Handel, is the V moving to a IV6:Print This Post Share