Unit 4: Harmony and Voice Leading I: Chord Function, Cadence, and Phrase

Harmonic function

The role a chord plays relative to the tonic in a key (how it creates stability, motion, tension, and resolution).

Tonic function

Harmonic “home base” that sounds stable and at rest (centered on I in major or i in minor).

Predominant function

Harmony that moves away from tonic and prepares dominant (commonly ii or IV; in minor, ii° or iv).

Dominant function

Tension-filled harmony that strongly pulls toward tonic, mainly because it contains tendency tones (commonly V/V7 and vii°).

Tonic (tonal center)

The “home” pitch and chord of a key; the point of departure and return in tonal music.

Diatonic triad

A three-note chord built by stacking thirds using only notes from the key (no chromatic pitches).

Roman numeral analysis

A chord-labeling system that identifies diatonic chords by scale-degree root (and often implies function).

Scale-degree position

A chord’s location in the key (which scale degree is the root), which largely determines its function more than its chord quality alone.

Tonic-prolongation chord

A chord that extends tonic stability without truly leaving tonic area (often vi or iii in major, depending on context).

Predominant chords (common)

Chords that typically lead into dominant harmony, especially ii and IV (or ii° and iv in minor).

Dominant chords (common)

Chords that create the strongest pull to tonic, especially V, V7, vii°, and vii°7.

Leading tone

Scale degree 7, which strongly tends to resolve up to scale degree 1.

Tendency tone

A scale degree with a strong conventional resolution, especially 7→1 and 4→3 (often within V7).

Raised leading tone (minor keys)

Raising scale degree 7 in minor to create a strong dominant (making V major and vii° diminished in functional harmony).

Harmonic progression

A series of chords in a specific order, understood in relation to the key and functional motion.

Functional arc (T–PD–D–T)

The common-practice “default” phrase plan: Tonic → Predominant → Dominant → Tonic.

V7 (dominant seventh chord)

A dominant chord with an added 7th that increases pull to tonic by adding/strengthening tendency tones and requiring resolution.

vii° (leading-tone triad)

A diminished triad built on scale degree 7 that functions as dominant because it contains the leading tone.

Inversion

A chord state determined by which chord member is in the bass; affects voice leading but usually not basic function.

Root position triad (5/3)

A triad with the root in the bass (intervals of a 3rd and 5th above the bass).

First inversion triad (6/3)

A triad with the 3rd in the bass (intervals of a 3rd and 6th above the bass); labeled with “6” in Roman numerals.

Second inversion triad (6/4)

A triad with the 5th in the bass (intervals of a 4th and 6th above the bass); labeled with “6/4” in Roman numerals.

Figured bass

Numbers (like 6 or 6/4) that indicate the intervals above the bass and thus the chord’s inversion in Roman numeral analysis.

Cadential 6/4

A tonic 6/4 (looks like I6/4) used at cadences as an embellishment of dominant, typically I6/4–V(7)–I (not a true tonic arrival).

Non-chord tone

A melodic (or inner-voice) note that does not belong to the underlying chord and decorates the harmony without changing it.

Suspension

A non-chord tone that is held over into a new harmony, creating dissonance and then resolving by step (often used at cadences).

SATB texture

Four-part chorale-style writing for soprano, alto, tenor, and bass used in AP Theory part-writing.

Voice leading

The craft of connecting chords by writing smooth, singable lines while maintaining clear harmony and stylistic conventions.

Outer voices

The soprano (highest) and bass (lowest) lines, which are most exposed and therefore have especially strict spacing and parallel-interval rules.

Contrary motion

Two voices move in opposite directions; especially useful for independence and avoiding parallels.

Oblique motion

One voice stays the same while another moves; also useful for avoiding parallels and stabilizing texture.

Parallel motion

Two voices move in the same direction by the same interval; problematic when it creates parallel 5ths/8ves/unisons.

Spacing rule (upper voices)

In SATB writing, keep soprano–alto and alto–tenor within an octave (tenor–bass may exceed an octave).

Voice crossing

A lower voice goes above a higher voice (e.g., tenor above alto), which obscures voice identity and is generally avoided.

Voice overlap

A lower voice moves above the previous note of a higher voice (or vice versa), making parts hard to follow; generally avoided.

Doubling (in SATB triads)

Because a triad has three notes but SATB has four parts, one chord member must be repeated (doubled).

Double the root (common guideline)

In root-position triads, doubling the root is the most reliable default because it strengthens the harmonic foundation.

Avoid doubling the leading tone

A key SATB rule: doubling scale degree 7 often forces awkward resolutions because both leading tones want to resolve up to 1.

Chordal seventh

The seventh added to a triad to form a seventh chord (often labeled with “7,” e.g., V7).

Chordal seventh resolution

In common-practice voice leading, the chordal seventh typically resolves downward by step, often into the next chord’s 3rd.

Parallel fifths

Two voices move in parallel from one perfect 5th to another, weakening independence (a standard AP error).

Parallel octaves

Two voices move in parallel from one perfect 8ve to another, making two parts sound like one (a standard AP error).

Hidden (direct) fifths/octaves

Two voices move in similar motion into a perfect 5th or 8ve while the upper voice leaps; especially exposed between soprano and bass.

Perfect Authentic Cadence (PAC)

Strongest cadence: V(7)→I (or V→i) with both chords in root position and the soprano ending on scale degree 1.

Imperfect Authentic Cadence (IAC)

V→I (or V→i) that is weaker than PAC due to inversion in V or I and/or soprano ending on scale degree 3 or 5.

Half Cadence (HC)

A cadence that ends on V, sounding like a pause or question; the preceding chord can vary as long as the phrase truly ends on V.

Phrygian Half Cadence (PHC)

A minor-key half cadence with iv6→V and a characteristic half-step descent in the bass into V (approaching scale degree 5 from above).

Deceptive Cadence (DC)

A dominant resolution that avoids expected tonic: most commonly V→vi in major or V→VI in minor.

Plagal Cadence (PC)

IV→I (or iv→i), often called the “Amen” cadence; typically weaker than authentic cadence because it lacks leading-tone drive.

Harmonic rhythm

The rate at which chords change; faster harmonic rhythm often increases tension, slower often increases stability (often slows near cadences).

Period

A two-phrase structure where the first phrase (antecedent) ends with a weaker cadence (often HC) and the second (consequent) ends with a stronger cadence (often PAC/IAC).

Elision (phrase overlap)

A phrase-ending cadence and the next phrase’s beginning occur together (the boundary overlaps, sometimes on the same beat).