Harmonic Analysis in Predominant Progressions (AP Music Theory Unit 5)

Harmonic Rhythm

What harmonic rhythm is

Harmonic rhythm is the rate at which the harmony changes in a piece of music—how often you get a new chord (or new harmony) as time moves forward. It’s different from the surface rhythm (the notes you see moving in the melody). A melody might have fast note values while the harmony underneath changes slowly, or vice versa.

In AP Music Theory, harmonic rhythm matters because you’re often asked to analyze or create chorales and short progressions that sound stylistically convincing. In common-practice tonal music (the main style for AP Theory’s part-writing), chord changes tend to happen in predictable places: frequently on strong beats, at the start of measures, or at important moments like cadences.

Why harmonic rhythm matters in harmonic analysis

Harmonic rhythm is one of the clearest ways music communicates structure:

• Phrase structure and cadences: Harmonic changes often speed up as you approach a cadence. That “tightening” helps the listener feel arrival.
• Function and direction: Unit 5 focuses heavily on chord progressions and predominant function (especially ii and IV). Predominants typically prepare dominants, and harmonic rhythm helps you hear that preparation as motion toward a cadence.
• Clarity in Roman numeral analysis: If you misjudge harmonic rhythm, you’ll label too many chords (or too few), and your analysis won’t match how the music actually behaves.

A useful analogy: harmonic rhythm is like the pacing of scene changes in a film. Even if characters talk quickly (fast melodic rhythm), the scene might stay the same (same harmony). When the scene changes (new chord), the story’s direction often changes too.

How harmonic rhythm works (and how you detect it)

When you’re analyzing a chorale-style texture (typical AP style), start by separating three layers:

1. Bass line: In tonal styles, the bass often signals chord changes first.
2. Vertical sonorities on strong beats: Chords are most likely to “mean something” structurally when they land on strong beats.
3. Non-chord tones (NCTs): Stepwise motions, suspensions, passing tones, neighbor tones, and anticipations can decorate a chord without changing the harmony.

A practical method to determine harmonic rhythm:

• Step 1: Mark the meter and strong beats. In 4/4, beats 1 and 3 are typically stronger than 2 and 4 (with beat 1 strongest).
• Step 2: Look at the bass on strong beats. If the bass changes by leap or outlines a functional pattern (like 4–2–5–1 in a major key), harmony is probably changing.
• Step 3: Check the upper voices for chord membership. Ask: “On this beat, do most notes belong to a single triad/seventh chord?”
• Step 4: Identify NCTs before declaring a new chord. A common mistake is calling every vertical sonority a new harmony—even when it’s clearly a passing sonority.

Common harmonic rhythm patterns in Unit 5 progressions

In Unit 5, you often see progressions built around tonic–predominant–dominant–tonic motion, with predominant function taking a central role.

Typical harmonic rhythm choices include:

• One chord per measure (slower harmonic rhythm): common in simple hymn-like phrases.
• Two chords per measure (moderate harmonic rhythm): especially near cadences, or when moving through predominant to dominant.
• Harmonic acceleration into a cadence: for example, a measure of tonic, then a measure split into predominant and dominant, then a cadence on tonic.

Here’s a way to think functionally about pacing:

This isn’t a rigid rule—composers vary harmonic rhythm for expressive reasons—but it’s a strong default for AP-style writing and analysis.

Harmonic rhythm vs. “chord-per-note” thinking (what goes wrong)

A major pitfall is assuming that every time a note changes, the chord changes. In chorale textures, inner voices frequently move stepwise as passing or neighbor tones, especially between chord tones. If you label each moment as a new Roman numeral, you’ll end up with progressions that look overly complex and often include “chords” that don’t behave like real functional harmonies.

A good diagnostic question is: Does this sonority behave like a structural harmony? Structural harmonies tend to:

• occur on strong beats,
• include stable chord members in multiple voices,
• make sense in functional syntax (tonic → predominant → dominant → tonic),
• support the phrase and cadence.

Example 1: Hearing harmonic rhythm in a simple phrase

Imagine a 4/4 phrase in C major where the bass notes on each measure are:

• Measure 1: C
• Measure 2: F
• Measure 3: G
• Measure 4: C

Even without every upper-voice note, this strongly suggests one chord per measure:

• m.1: I
• m.2: IV (predominant)
• m.3: V (dominant)
• m.4: I (tonic resolution)

That’s a classic tonic–predominant–dominant–tonic plan, with harmonic rhythm = one chord per measure.

Now imagine a slight intensification approaching the cadence:

• Measure 1: C in bass (I for the whole measure)
• Measure 2: F on beat 1, then G on beat 3 (IV → V within one measure)
• Measure 3: C (I)

Here the harmonic rhythm accelerates in measure 2 (two chords in one measure) to heighten the cadence drive.

Example 2: Not over-labeling passing motion

Suppose in C major you see this in the bass across a measure of 4/4:

• Beat 1: C
• Beat 2: B
• Beat 3: A
• Beat 4: G

It’s tempting to label four different chords, but in chorale style this could easily be a bass passing line connecting I (C) to V (G), with B and A as passing tones or as part of a linear motion within a larger harmonic plan. Your job in harmonic analysis is to decide whether those intermediate beats actually establish functional harmonies (supported by upper voices) or whether they are embellishing a slower harmonic rhythm.

Exam Focus

• Typical question patterns:
  • Identify Roman numerals and inversions in a short excerpt where harmonic rhythm is not “one chord per beat,” requiring you to treat some notes as non-chord tones.
  • Compare two possible analyses and choose the one that matches strong-beat harmonies and functional syntax.
  • In part-writing or harmonization, choose chord changes that fit a given meter and cadence plan.
• Common mistakes:
  • Labeling every vertical sonority as a new chord instead of recognizing passing/neighbor motion.
  • Placing predominant or dominant chords on weak beats in a way that weakens cadences (unless clearly supported stylistically).
  • Ignoring the bass line as the primary harmonic guide.

Harmonizing Melodies

What “harmonizing a melody” means in AP Music Theory

Harmonizing a melody means choosing chords (and typically writing additional voices) that support a given tune in a stylistically appropriate way. In AP Music Theory contexts, this usually involves:

• choosing Roman numerals that make functional sense,
• using inversions that create a smooth bass line,
• applying correct voice-leading rules (spacing, doubling, tendency tones, avoiding parallels),
• handling non-chord tones correctly,
• and shaping phrases with convincing cadences.

Even when a task looks like “just add chords,” the deeper skill being tested is your understanding of tonal syntax: melodies imply harmony through scale degrees, leaps, tendency tones (like 7 in major), and cadential patterns.

Why it matters (and how it connects to Unit 5 predominant function)

Unit 5 emphasizes chord progressions and especially predominant function—chords like ii and IV that typically lead to V (or sometimes to cadential 6/4 and then V). When you harmonize melodies, the biggest difference between a beginner solution and a convincing solution is often whether predominant harmony is used effectively.

If your harmonization jumps from I straight to V too often, the phrase may sound harmonically thin. Predominants provide preparation and forward motion, making cadences sound inevitable rather than abrupt.

A reliable process: from melody to functional plan

A strong approach is to plan in layers, moving from large-scale structure to details.

Step 1: Find the key and phrase goals

Start by confirming the key (look at the key signature and the melodic emphasis on tonic). Then identify phrase endings:

• Does the melody end on scale degree 1 (tonic) with a sense of closure? That often implies an authentic cadence area (V to I).
• Does it end on scale degree 2 or 5 with a pause-like feeling? That can imply a half cadence (ending on V).

You don’t need to name the cadence type perfectly at first, but you should decide where the harmony must move to dominant and where it must resolve.

Step 2: Mark “structural” melody notes vs. embellishing notes

Not every melody note needs a new chord. Circle or mentally note:

• notes on strong beats,
• longer notes,
• leaps (especially if they outline a triad),
• and notes at phrase beginnings/endings.

Fast stepwise notes between strong beats are often non-chord tones.

A common misconception: “Every melody note must be a chord tone.” In real tonal melodies (and AP-style), non-chord tones are normal and expected.

Step 3: Choose a harmonic rhythm that fits the meter and style

Decide how frequently chords should change (often one or two chords per measure in chorale style). Then commit to it unless you have a clear reason to vary it. This prevents “analysis by panic,” where you change chords too often to accommodate every note.

Step 4: Build a functional progression skeleton (T–PD–D–T)

For each phrase, sketch a basic functional path:

• Start in tonic (often I).
• Move into predominant (ii or IV) somewhere in the middle—especially before a cadence.
• Move to dominant (V or vii°) near the cadence.
• Resolve to tonic if it’s a closing cadence.

In major keys, common predominant choices:

• ii6 is extremely common because it avoids some doubling/spacing issues and tends to lead smoothly to V.
• IV (or IV6) is also common, especially when the melody contains scale degree 4 or 6.

In minor keys, ii is often diminished (ii°), so you must be careful about quality and voice-leading; iv and ii°6 are common predominant sounds.

Step 5: Fit chords to melody notes (prioritize chord tones on strong beats)

Now match the melody’s structural notes to chord members. For each strong-beat melody note, ask: “Which functional chord could contain this note while also moving the phrase toward its cadence?”

For example in C major:

• Melody note E could fit I (C–E–G), iii (E–G–B), vi (A–C–E), or IV6 (F–A–C with E as a non-chord tone, so not that one).
• But function matters: iii is rarely used as a strong predominant in basic chorale syntax, so you’d more likely choose I or vi depending on context.

This is where Unit 5’s functional emphasis comes in: you’re not just picking any chord that “contains the note,” you’re choosing one that behaves correctly.

How predominant function shows up when harmonizing

Predominants often appear in predictable spots:

• After tonic prolongation at the start of a phrase: I may last a while, decorated by passing tones or by a neighbor chord like V6/4 in some contexts, but eventually you move away.
• Before dominant near cadences: ii or IV typically precedes V.

A very common cadential approach in four-part chorale style is:

• ii6 → V (or V7) → I

Why ii6 specifically? Because in many keys, ii6 places the chord’s third in the bass, which often creates a smooth stepwise bass approach to V.

Inversions and bass-line planning (making it sound musical)

Even if your chord choices are correct, the harmonization can sound awkward if the bass line leaps unnecessarily. In AP-style writing, inversions are a main tool for controlling bass motion.

Guidelines that usually improve results:

• Use root position (especially I and V) to articulate strong structural points (beginnings, cadences).
• Use first inversion (6 chords) to smooth the bass and reduce awkward leaps.
• Aim for bass lines that move by step or small skips when possible, especially into cadences.

For predominant chords:

• ii6 often leads nicely to V because the bass can move by step.
• IV6 can also function smoothly, depending on the key and melodic content.

What goes wrong: students sometimes put every chord in root position. The result is a bass line that jumps around, making the phrase feel clunky and making voice-leading errors (like parallels) more likely.

Non-chord tones in melodies: how to harmonize without “chasing notes”

A melody frequently includes non-chord tones such as:

• Passing tones: stepwise motion between two chord tones.
• Neighbor tones: step away from a chord tone and return.
• Suspensions: a note held over that creates a dissonance that resolves down by step.
• Anticipations: an early arrival of a chord tone from the next harmony.

When harmonizing, the key skill is to keep the harmony steady while the melody decorates it, unless there’s a strong-beat reason to change chords.

Example idea (C major): if the melody goes G–A–G over two beats, that A might be a neighbor tone, and the harmony could remain I (if the rest of the texture supports it). You do not need to change to ii just because A appears.

Worked example: harmonizing a short melody (functional plan first)

Let’s model the thinking process with a simple, chorale-like phrase in C major, 4/4. Melody (one measure per bar):

• m.1: E (half note), D (half note)
• m.2: C (half), D (half)
• m.3: E (half), F (half)
• m.4: G (whole note)

Assume this is a phrase ending on G, so it likely ends with a half cadence (ending on V).

Step A: Choose harmonic rhythm. One chord per half measure (two chords per measure) is a reasonable pace for a short phrase, but since the melody is mostly half notes, one chord per half note aligns naturally.

Step B: Plan the cadence. To end on V in m.4, we likely want predominant before it:

• m.3: predominant (ii or IV)
• m.4: V

Step C: Fit chords to strong melody notes.

• m.4 melody is G, which is the root of V (G–B–D). So choose V in m.4.
• m.3 has E then F. F strongly supports a predominant like IV (F–A–C) or ii6 (D–F–A with F in the chord). Since we’re aiming at V next, ii6 is a classic predominant.
• m.1 and m.2 can establish tonic and move gently toward predominant.

One possible Roman numeral plan (two harmonies per measure):

• m.1 (E): I (melody E is chord tone)
• m.1 (D): V6 (in C major, V is G–B–D; D can be chord tone; V6 helps avoid a heavy dominant too early)
• m.2 (C): I (melody C is chord tone)
• m.2 (D): ii6 (melody D is chord tone; also sets up predominant)
• m.3 (E): I6 (a brief tonic expansion before the cadence drive)
• m.3 (F): ii6 (predominant clearly stated)
• m.4 (G): V (half cadence)

Is this the only solution? Not at all. But notice what makes it stylistically strong:

• It uses predominant (ii6) immediately before V.
• It places the cadence goal (V) clearly at the end.
• It avoids changing harmony just to accommodate every pitch—each chord supports multiple melody notes.

If you were writing four parts, you’d next choose bass notes that match the inversions, then fill alto/tenor with chord tones (watch doubling and tendency tones), and finally check for parallels and spacing.

Another worked example: closing with an authentic cadence

Now imagine the phrase ends on C (scale degree 1) with a strong sense of closure. A very common cadential plan in C major is:

• ii6 → V7 → I

Suppose the last two measures of melody are:

• m.3: F (half), E (half)
• m.4: D (half), C (half)

A functional approach:

• Put ii6 under F (since F is in D–F–A).
• Move to V7 under E or D (both can belong to V7: G–B–D–F; E could be a passing tone depending on placement).
• Resolve to I under C.

What to watch: if you use V7, its chordal seventh (F in C major) should resolve downward by step in the appropriate voice when you write the texture. Students often forget that resolution and lose the “pull” of the dominant.

Practical voice-leading checks while harmonizing (the things that silently wreck scores)

Even though this section is “harmonic analysis,” AP questions often blend harmony choice with voice-leading expectations—especially in harmonization/free-response contexts. While you’re choosing chords for a melody, keep these in mind:

• Don’t double tendency tones unnecessarily (especially the leading tone, scale degree 7, in major keys).
• Watch for parallel fifths and octaves between soprano and bass (and other voice pairs). Strong-beat parallels are especially noticeable.
• Resolve tendency tones correctly: leading tone tends to resolve to tonic; chordal sevenths tend to resolve down by step.
• Use inversions to smooth the bass and reduce big leaps that make parallels more likely.

A common misconception is thinking that “correct chords” automatically produce a correct harmonization. In AP-style writing, chord choice and voice leading are inseparable: a chord that works on paper may be impractical if it forces repeated parallels or unresolved tendencies.

How to write Roman numerals clearly when harmonizing

When you commit to a harmony under a melody note, label it in a way that communicates:

• Chord root and quality: Roman numeral (uppercase for major, lowercase for minor, diminished symbol when appropriate).
• Inversion: figured bass (6 for first inversion triads, 6/4 for second inversion triads; seventh chords include 7, 6/5, 4/3, 4/2).

In Unit 5 contexts, inversion labeling matters because predominant function is often expressed through first inversion chords (like ii6), and cadential patterns often involve specific inversions.

Exam Focus

• Typical question patterns:
  • Given a melody (sometimes with bass), choose a chord progression using Roman numerals, often requiring predominant chords (ii or IV) before cadences.
  • In a short excerpt, identify which melody notes are chord tones vs. non-chord tones and label harmonies accordingly.
  • Write or justify a cadence plan (half cadence vs. authentic cadence) based on the melody’s ending and harmonic syntax.
• Common mistakes:
  • “Chord chasing”: changing harmony for every melody pitch instead of recognizing passing/neighbor tones.
  • Skipping predominant function and going I → V too often, producing weak or abrupt cadences.
  • Picking chords that contain the melody note but don’t make functional sense (for example, overusing iii in places where a predominant is expected).