AP Music Theory Unit 5: Harmony and Voice Leading II: Chord Progressions and Predominant Function

Subdominant (IV or iv) and Supertonic (ii or iiº) Triads

  • IV chord can prolong tonic via neighbor motion

    • prolongation

      • make chord span longer span of time without it sounding

  • can serve as predominant

    • chord that goes before the dominant

  • ii can sub for the IV bc share common tones

    • usually in 1st inversion (ii6)

    • in minor, triad is diminished

First Inversion Triads

  • known as 6 chords

  • weaker than root position triads

  • when part writing, double any note expect for the LT or the lowered scale degree 6 in minor

  • can be used in neighbor progression to improve contour of baseline

    • neighbor V6 chord must resolve to the I in root position

  • can be used to prolong chords

  • iv6 chord used in Phrygian half cadence

Second Inversion Triads

  • known as 6/4 chords

  • least stable

  • usually dissonant bc interval of 4th

  • must be prepared and resolved

Types of Second Inversion Triads

  • passing 6/4

    • connect root position triad w first inversion

    • can be used to prolong chords

      • tonic most common

  • neighbor (pedal) 6/4

    • bass is static and often sustained

  • cadential 6/4

    • prepares a cadence (HC, IAC, PAC)

    • embellishment of V chord

    • melodic line is usually 3-2-1

The Leading Tone Triad (viiº6)

  • written in first inversion

  • contains a tritone

  • can sub for the dominant bc share common tones

  • most common use in a passing progression

  • can be used in leading tone IAC

The Mediant Triad (iii or III)

  • based on 3rd scale degree

    • can sub for I6 bc share CTs

    • commonly used in progression I-iii-IV-V

  • LT does not need to be resolved as it has less tension

  • in minor 7th scale degree is not raised in III chord

The Submediant Triad (vi or VI)

  • based on 6th scale degree

    • can sub for tonic and subdominant

    • often used in descending 3rd progressions

    • used in deceptive cadences

  • mediant can be adjacent to the submediant in chord progressions

The Subtonic (VII) Triad

  • usually in minor

  • based on lowered 7th scale degree

  • tends to interact w III as the area. 5th apart

  • can be used to modulate (Change key) to the relative major

Other Diatonic Sevenths

Part-Writing w Diatonic Sevenths

  • leading tone 7th (viiº7 or viiº7)

    • can sub for V7

    • in 3rd inversion, it can go tot he dominant

    • fully diminished 7th in minor can also be used to modulate

  • supertonic 7th (ii7 or iiº7)

    • usually functions as a predominant