Secondary triads reinforce modality. They do not occur as frequently as primary triads, which reinforce tonality. Secondary triads are used in harmonic progressions to create variety.
Principles of chord progression may be discussed with the addition of secondary triads to primary triads. The tonic chord is considered separately when describing chord progression because all chord progressions move toward the tonic. The remaining chords are assigned to Groups (Classifications) which relate generally to the function of the chords.
Group 1 (First Classification) chords are the major dominant and diminished leading tone chords and have a dominant function. The first inversion augmented mediant triad found in harmonic and ascending melodic minor is in this group because of its similarity to the dominant chord.
Group 2 (second Classification) chords are the subdominant and supersonic chords and have a subdominant function.
The Group 3 (Third Classification) chord is the submediant and may have a tonic function.
The Group 4 (Fourth Classification) chord is the mediant and may have a tonic or dominant function.
FIGURE 9.1: Chord Chart
Dominant relationship is the association of two chords whose roots area perfect fifth apart. Dominant relationship prevails when the chord Groups are assembled from Group 4 through Group 1 and then the tonic.
FIGURE 9.2: Dominant Relationship
An established tonic chord occurs whenever a dominant function chord progresses to the tonic chord. Any chord may follow an established tonic chord. Any chord may follow itself. Chords generally change from weak to strong rhythmic position unless they are of long duration.
FIGURE 9.3: Chord Progression
Normal chord progression occurs after an established tonic chord, when chords progress from left to right through each successive group.
FIGURE 9.4: Normal Chord Progression
Elision in a chord progression occurs when one chord group is skipped in left to right movement. Elision must be followed by normal chord progression. iii(III) to IV(IV) and vi(VI) to V(V#) are common examples of elision.
FIGURE 9.5: Elision
A neutral tonic chord occurs when a tonic chord appears between any two chords in a progression or between two positions of the same chord. Neutral tonic chords usually occur with normal progression.
FIGURE 9.6: Neutral Tonic Chord Retrogression occurs when chords move from right to left on the chord chart. Retrogression is usually followed by normal movement.
FIGURE 9.7: Retrogression
chord in minor often has a dominant function because it is similar to the
dominant chord. The chord may be described as a dominant chord with an unresolved
FIGURE 9.8: III