Glossary
Circle of Fifths
A visual representation of the relationships among the 12 chromatic pitches, showing the progression of keys or chords by perfect fifths.
Example:
Understanding the Circle of Fifths helps a composer modulate smoothly between keys or predict common chord progressions.
Contrary Motion
A type of voice leading where two musical lines move in opposite directions. For example, one voice ascends while the other descends.
Example:
To ensure smooth voice leading and avoid parallels, the bass line often moves in contrary motion to the upper voices.
Parallel Fifths
A voice leading error where two parts that are a perfect fifth apart move in the same direction to another perfect fifth. This is generally avoided in common practice harmony.
Example:
If the bass and tenor voices both move from C-G to D-A, they create parallel fifths, which can sound hollow or unmusical.
Parallel Octaves
A voice leading error where two parts that are an octave apart move in the same direction to another octave. This is also generally avoided in common practice harmony.
Example:
When the soprano and bass voices both move from C to D, maintaining an octave interval, they create parallel octaves, which can diminish the independence of the voices.
Predominant Harmonies
Chords (ii and IV in major, ii° and iv in minor) that lead to the dominant (V) chord. They act as a preparatory step before the dominant.
Example:
In a piece, the composer might use a predominant harmony like a C major IV chord before moving to a G major V chord in the key of G major.
Subdominant (IV/iv)
The IV chord in major keys or iv chord in minor keys, serving as a common predominant harmony. It is a perfect fifth below the tonic.
Example:
In C major, the F major chord is the Subdominant (IV), often used to set up the dominant G major chord.
Supertonic (ii/ii°)
The ii chord in major keys or ii° (diminished) chord in minor keys, functioning as a predominant harmony. It is considered a weaker substitute for the IV chord.
Example:
In G major, an A minor chord is the Supertonic (ii), which can add harmonic interest before the dominant D major.
T-D-T progression
A basic harmonic progression consisting of Tonic (T), Dominant (D), and Tonic (T) chords. It represents a fundamental musical phrase structure.
Example:
A simple folk song might end with a clear T-D-T progression, providing a strong sense of arrival and resolution.
T-PD-D-T progression
An expanded harmonic progression that includes a Predominant (PD) chord between the Tonic (T) and Dominant (D). This creates a stronger sense of harmonic movement.
Example:
Many classical melodies utilize a T-PD-D-T progression to build tension and release, making the harmonic journey more engaging.
Voice Leading
The melodic movement of individual lines or 'voices' within a chord progression. Good voice leading ensures smooth and musically logical transitions between chords.
Example:
When harmonizing a melody, careful voice leading ensures that each part moves smoothly, avoiding awkward leaps or forbidden parallels.