Unit 3: Music Fundamentals III: Triads and Seventh Chords

From Intervals to Chords: Building Harmony in Thirds

A chord is a collection (or group) of multiple pitches that sound at the same time and form a single harmonic idea. In AP Music Theory, most of the harmony you analyze and write is built by stacking thirds above a starting note. That starting note is called the root. Learning to hear and identify the root (even when it is not the lowest note) is one of the most important skills in tonal music.

Stacking thirds matters because, in common-practice tonal music (the main style AP Music Theory focuses on), it produces chord types that composers most frequently use for functional harmony. These chords have predictable “jobs” in a key: some feel stable (home), some create motion, and some create tension that wants to resolve.

Before you can build triads and seventh chords confidently, two ideas need to feel automatic:

1. Letter-name spacing matters. A third means “skip one letter name” (C to E, D to F, etc.) regardless of accidentals.
2. Quality depends on exact semitone distance. Once the letters are correct, accidentals determine whether the interval is major, minor, diminished, etc.

Stacking thirds carefully (the non-negotiable method)

When you build chords, always do it in this order:

1. Pick a root (letter name first).
2. Stack the next chord tone a third above (skip one letter).
3. Stack the next chord tone another third above.
4. Add accidentals only after the letter skeleton is correct.

This prevents one of the most common errors: building something that sounds right on a keyboard but is spelled incorrectly on the staff. AP scoring cares about correct spelling.

Example: building in a key vs. building by “sound”

If you are in the key of D major and you build a triad on scale-degree 2:

• Scale-degree 2 is E.
• Stack thirds using the key signature: E–G–B.
• In D major, G is natural (not G♯), so the chord is E–G–B.

That chord is E minor, and that quality comes from the key, not from guessing.

Exam Focus

• Typical question patterns:
  • “Build a triad/seventh chord on a given scale degree in a specified key.”
  • “Spell a chord from a Roman numeral and inversion.”
  • “Identify chord members (root, third, fifth, seventh) in a given chord.”
• Common mistakes:
  • Using correct-sounding pitches but wrong spellings (especially in minor keys).
  • Forgetting that a third is defined by letter names first, not by keyboard distance.
  • Assuming the lowest note is the root (it often is not).

Triads: Structure, Quality, and Stability

A triad is a three-note chord built from two stacked thirds. The chord members are:

• Root: the pitch the chord is built on (in root position, this is the lowest-sounding note)
• Third: a third above the root (in stacked-third form, it’s the “middle” note)
• Fifth: a fifth above the root (also a third above the third; in stacked-third form, it’s the “upper” note)

Triads matter because they are the basic harmonic “words” of tonal music. Most progressions you analyze—cadences, tonic-dominant motion, tonic prolongation—are built from triads, and seventh chords usually behave like “intensified” triads.

Triad qualities (major, minor, diminished, augmented)

Triad quality is determined by the quality of the intervals above the root:

• Major triad: major third + perfect fifth above the root
• Minor triad: minor third + perfect fifth
• Diminished triad: minor third + diminished fifth
• Augmented triad: major third + augmented fifth

A practical way to remember this is to focus on the two stacked thirds:

• Major triad = major third + minor third (top third is smaller)
• Minor triad = minor third + major third (top third is larger)
• Diminished triad = minor third + minor third
• Augmented triad = major third + major third

Worked example: identify triad quality from pitch spelling

Chord: A–C–E

1. Check letter names: A to C is a third; A to E is a fifth.
2. Recognize interval qualities: A to C is a minor third, and A to E is a perfect fifth.
3. Minor third + perfect fifth means A minor triad.

Chord: B–D–F

• B to D is minor third; B to F is diminished fifth.
• That is a B diminished triad.

Diatonic chords (what “diatonic” means)

Diatonic chords are chords derived from the notes of a particular key. They are built using only the notes of the major scale or minor scale of that key. There are seven diatonic chords in each key, one built on each scale degree.

Diatonic triads in major keys (the “built-in” qualities)

When you stack diatonic thirds on each scale degree in a major key, you always get the same pattern of triad qualities:

A quick functional snapshot is that I, IV, and V are major, ii, iii, and vi are minor, and vii° is diminished.

Diatonic triads in minor keys (and why minor is trickier)

In minor, the default scale (natural minor) gives you one set of triads, but real tonal music frequently raises scale-degree 7 (harmonic minor) and sometimes raises scale-degrees 6 and 7 (melodic minor). That means chord qualities in minor depend on context.

If you build diatonic triads in natural minor, you get:

A quick functional snapshot is that i, iv, and v are minor, III, VI, and VII are major, and ii° is diminished.

The subtonic triad (natural minor)

The subtonic triad is the triad built on scale-degree 7 in natural minor. It is a major chord and sits a whole step below the tonic (because scale-degree 7 is the subtonic, not a leading tone, in natural minor).

Commonly used major triads from natural minor

Natural minor frequently features major triads such as:

• Major mediant (III)
• VII (the subtonic triad)

The dominant in minor usually borrows from harmonic minor

In common-practice harmony, you often see V (major) and vii° in minor, which require raising scale-degree 7 to create a leading tone. This is a big conceptual point: dominant function in minor is usually borrowed from harmonic minor.

Example: V in A minor

• Natural minor scale-degree 5 triad would be E–G–B (v, minor).
• To create a stronger dominant, raise G to G♯:
  • E–G♯–B = V (major).

If you forget to raise the leading tone, your cadence in minor will sound weak and will often be marked wrong in AP-style part-writing.

Exam Focus

• Typical question patterns:
  • “Identify the quality of a triad given pitches.”
  • “Write all diatonic triads in a given key, labeling with Roman numerals.”
  • “In minor, choose the correct form (natural/harmonic/melodic) to build V or vii°.”
• Common mistakes:
  • Treating minor keys as if they have a single fixed set of chords (they don’t).
  • Mislabeling diminished triads (especially vii° in major and ii° in minor).
  • Building a chord with incorrect letter names (for example, spelling a third as some kind of second).

Inversion and Figured Bass: Hearing and Labeling Chords Beyond Root Position

A chord is in root position when the root is the lowest sounding note. A chord is in an inversion when a chord member other than the root is in the bass.

Inversion matters for two big reasons. First, sound and stability change: root-position chords tend to feel more stable and final, while inversions can sound lighter, smoother, or less final. Second, inversions give voice-leading control: they help keep the bass line moving stepwise or smoothly, which helps avoid awkward leaps and parallels.

Triad inversions

Triads have three possible bass notes, so they have three positions:

• Root position: root in bass
• First inversion: third in bass
• Second inversion: fifth in bass

Figured bass (what it is and what it’s for)

Figured bass consists of a bass line with Arabic numbers under the bass that represent the intervals above the bass to be played. The specific voicing of the chord and the linear movement of each line is often determined by the performer (or, on the AP exam, by your part-writing choices), as long as the required intervals and stylistic norms are met.

A key purpose of inversion symbols (figures attached to Roman numerals like 6 or 6/4) is to indicate the lowest-sounding chord member.

Figured bass for triads

For triads, the common inversion figures are:

A crucial understanding: figured bass labels intervals above the bass, not above the root. That’s why first inversion shows a 6: the root is now a sixth above the bass.

Inversion figures vs. full figured bass markings

The Arabic numbers that show inversion (like 6, 6/4, 6/5, 4/3, 4/2) indicate intervals above the bass, just as in figured bass. However, added accidentals, slashes, or plus signs that may appear in a fully notated figured bass line are part of the accompaniment/realization detail and are not included when you write inversion figures in Roman numeral analysis.

Connecting Roman numerals and inversion

Roman numerals label a chord’s root by scale degree; figured bass labels inversion.

Example in C major:

• E–G–C has E in bass, and the chord tones spell a C major triad.
• The root is C, so the Roman numeral is I.
• With the third (E) in the bass, it is first inversion: I6.

A common sticking point: the Roman numeral does not change just because the bass note changes.

Quick “root-finding” method (especially helpful on exams)

If you are given three notes and asked for the Roman numeral:

1. Try stacking them in thirds (rearrange notes conceptually).
2. The bottom of that stacked-third structure is the root.
3. Identify the quality and scale degree in the key.
4. Then identify inversion by checking what note is in the bass of the actual voicing.

Example: identify a triad and inversion

Key: G major
Chord tones shown: B–D–G, with D in the bass.

• Stack in thirds: G–B–D is a G major triad.
• In G major, G is scale-degree 1, so Roman numeral is I.
• Bass is D (the fifth of the chord), so it’s second inversion.
• Label: I6/4.

Exam Focus

• Typical question patterns:
  • “Given a chord in staff notation, label it with Roman numeral and inversion.”
  • “Realize a bass line with figures (especially 6 and 6/4) into four parts.”
  • “Choose the correct inversion to create a smooth bass line.”
• Common mistakes:
  • Naming the chord by the bass note instead of the root.
  • Mixing up 6/4 (second inversion triad) with 4/2 (third inversion seventh chord).
  • Writing figures as if they describe the chord in root position rather than intervals above the bass.

Roman Numerals and Chord Function: Putting Triads Into a Key

Roman numeral analysis names chords by their scale-degree roots and their qualities, inside a specific key. This matters because tonal harmony is not just “chords in isolation” but chords behaving in patterns that listeners recognize.

A Roman numeral typically communicates:

• Scale degree of the root (I, ii, V, etc.)
• Quality (uppercase for major, lowercase for minor, diminished symbol for diminished)
• Inversion (figured bass numbers)

Roman numerals: quality conventions you must get right

• Uppercase (I, IV, V) = major triad
• Lowercase (i, iv, v) = minor triad
• Diminished triad = lowercase with degree symbol (vii°)
• Augmented triad (less common diatonically) = uppercase/lowercase with plus sign (for example, III+), when appropriate

In AP free-response scoring, these symbols are not cosmetic. A correct root but wrong quality is a wrong chord.

Harmonic function (the “why” behind Roman numerals)

In basic tonal harmony, chords tend to fall into three functional families:

• Tonic function: feels like rest, home, stability (often I, sometimes vi, sometimes iii)
• Predominant function: moves away from tonic, sets up dominant (often ii or IV)
• Dominant function: creates tension that resolves to tonic (V and vii°)

Thinking in function helps you predict what comes next. For example, if you see ii6, it is very likely heading to V (or V7). If you see V, you should expect I soon.

Example progression in C major (function-focused)

• I (tonic)
• ii6 (predominant)
• V (dominant)
• I (tonic)

Common pitfall: treating inversions as “different chords”

I, I6, and I6/4 are all the tonic triad, just in different bass positions. Their effect is different, but their identity (root and function) is related. This matters because in analysis you are often tracking a prolonged harmony where inversions decorate or connect.

Exam Focus

• Typical question patterns:
  • “Analyze a phrase using Roman numerals with inversions.”
  • “Identify predominant and dominant harmonies in a cadence.”
  • “Choose a chord that best fits a harmonic function at a given moment.”
• Common mistakes:
  • Writing the wrong case (V instead of v, or IV instead of iv) in minor.
  • Forgetting the diminished symbol on vii° or ii°.
  • Confusing function with inversion (for example, assuming all 6/4 chords are tonic).

Seventh Chords: Adding a Third to Create More Tension and Direction

A seventh chord is a four-note chord built by stacking three thirds. The chord members are:

• Root
• Third
• Fifth
• Seventh (a seventh above the root)

Seventh chords matter because they increase tension and forward motion. In tonal style, the presence of a chordal seventh creates dissonance, which makes the sonority overall less stable and often pushes the music toward resolution.

Five basic seventh-chord qualities (the common types)

Seventh chords are named by the triad quality plus the quality of the seventh above the root:

• Major-major seventh (often just “major seventh”): major triad + major seventh
• Dominant seventh: major triad + minor seventh
• Minor-minor seventh (often just “minor seventh”): minor triad + minor seventh
• Half-diminished seventh: diminished triad + minor seventh
• Fully diminished seventh: diminished triad + diminished seventh

A helpful precision point: “dominant seventh” is a specific quality (major triad + minor seventh), not merely “a seventh chord on V.” In diatonic tonal music it is most associated with V.

Diatonic seventh chords in major

In a major key, stacking diatonic thirds yields this pattern:

Seventh chords in minor (why you must watch scale-degree 7)

In minor, seventh chords depend strongly on whether scale-degree 7 is raised.

• In natural minor, the chord on 7 is VII7 (often major-minor seventh), not a leading-tone chord.
• In harmonic minor, raising 7 creates leading-tone diminished seventh chords and makes V7 much more common.

In AP-style part-writing and analysis, V7 in minor nearly always uses the raised leading tone. In that sense, the diatonic V7 you build in major and the V7 you build in harmonic minor share the same chord quality (dominant seventh), but in minor you must remember the accidental that creates the leading tone.

Example: build V7 in D minor

• Scale-degree 5 is A.
• Build a seventh chord by thirds: A–C–E–G.
• To make it a true dominant in D minor, raise scale-degree 7: C becomes C♯.
• Result: A–C♯–E–G, which is V7 in D minor.

Fully diminished seventh chords in minor

The fully diminished seventh chord (diminished triad + diminished seventh) commonly occurs on the leading tone in harmonic minor. It is extremely tense and resolves strongly.

Exam Focus

• Typical question patterns:
  • “Spell a seventh chord (often V7) in a given key.”
  • “Identify the quality of a seventh chord from its notes.”
  • “Label diatonic seventh chords with correct Roman numerals (including ø and ° where needed).”
• Common mistakes:
  • Forgetting that viiø7 in major is half-diminished (ø), not fully diminished.
  • Misbuilding V7 in minor without raising the leading tone.
  • Labeling by chord quality but choosing the wrong Roman numeral for the key.

Inversion and Figured Bass for Seventh Chords

Like triads, seventh chords can appear in inversions. Since there are four chord members, there are four possible bass notes:

• Root position: root in bass
• First inversion: third in bass
• Second inversion: fifth in bass
• Third inversion: seventh in bass

Inversions are extremely common with seventh chords because they help voice leading: you can keep common tones, move voices by step, and create a smoother bass line.

Figured bass for seventh chords (and what the figures “mean”)

For seventh chords, the standard inversion figures are:

Another way to remember what’s happening is to think in “where is the root above the bass?”

• In first inversion (third in the bass), the root lies a sixth above the bass.

6/5

• In second inversion (fifth in the bass), the root lies a fourth above the bass, and the added seventh of the chord lies a third above the bass.

4/3

• In third inversion (seventh in the bass), the root lies a second above the bass (since a second is the inversion of a seventh).

4/2

A frequent confusion is between triad 6/4 and seventh-chord 4/2. They are completely different sonorities:

• 6/4 = triad in second inversion (three notes)
• 4/2 = seventh chord in third inversion (four notes)

Mnemonic: the “Inversion Hotline”

An easy way to remember the inversion figures is:

Inversion Hotline: 664-765-4342

This strings together the common figures: 6/4, 6/3, 7, 6/5, 4/3, 4/2.

Example: label a seventh chord and inversion

Key: F major
Chord tones: E–G–B♭–D, with G in the bass.

1. Stack in thirds: E–G–B♭–D is built on E.
2. In F major, E is scale-degree 7.
3. The chord is E–G–B♭ (diminished triad) plus D (a minor seventh above E) → half-diminished seventh.
4. Roman numeral: viiø7.
5. Bass note is G, which is the third of the chord → first inversion.
6. Figured bass: 6/5.

Final label: viiø6/5.

Exam Focus

• Typical question patterns:
  • “Identify seventh-chord inversions from the bass note and figures.”
  • “Write a specified seventh chord (like V4/3 or viiø6/5) in SATB.”
  • “Analyze a passage that uses inversions to smooth the bass line.”
• Common mistakes:
  • Writing 6/5 when the bass is actually the fifth (should be 4/3).
  • Forgetting that third inversion is labeled 4/2 (or 2).
  • Finding the root by looking at the bass instead of stacking in thirds.

Chord Symbols and Lead-Sheet Notation: A Second Naming System

In addition to Roman numerals (which are key-based), musicians often use chord symbols (also called lead-sheet symbols) that name chords by letter and quality. This system is common in popular music, jazz, and practical rehearsal contexts, and AP Music Theory expects you to recognize it even though Roman numerals are the main analysis language.

Chord symbols matter because they are a real-world way musicians communicate harmony quickly. They also train you to think of chords as transposable structures.

Common chord symbol conventions

• Major triad: C (often no quality marking)
• Minor triad: Cm or Cmin
• Diminished triad: Cdim or C°
• Augmented triad: Caug or C+
• Dominant seventh: C7
• Major seventh: Cmaj7 or CΔ7
• Minor seventh: Cm7
• Half-diminished seventh: Cø7 (often written as Cm7♭5 in some styles)
• Fully diminished seventh: C°7

Be careful: In chord symbols, “C7” does not mean “a chord in the key of C.” It means a C dominant seventh chord (C–E–G–B♭).

Slash chords (inversions in chord-symbol world)

A slash indicates a specific bass note:

• C/E means a C major chord with E in the bass (first inversion).

Connecting chord symbols to Roman numerals

Roman numerals require a key; chord symbols do not.

Example: In the key of F major, a G minor triad is ii.

• Roman numeral: ii
• Chord symbol: Gm

Both refer to the same chord tones, but Roman numerals explain function inside the key.

Exam Focus

• Typical question patterns:
  • “Interpret a chord symbol and spell the chord.”
  • “Translate between a chord symbol and a Roman numeral (given a key).”
  • “Recognize inversions indicated by slash chords.”
• Common mistakes:
  • Interpreting “C7” as “C major with an added 7th” (it’s specifically dominant seventh with B♭).
  • Confusing Cmaj7 with C7.
  • Forgetting that slash chords specify bass, not a second chord.

Tendency Tones and Resolution Basics in Triads and Seventh Chords

In tonal harmony, many chord tones have predictable “gravitational pull.” These are called tendency tones, notes that strongly prefer to move in a particular direction by step.

This matters because AP Music Theory includes part-writing and harmonic analysis where you must choose chord spellings and voice leading that sound stylistically correct.

The leading tone (scale-degree 7)

The most important tendency tone is the leading tone (scale-degree 7) in major and harmonic/melodic minor. It strongly tends to resolve up by step to scale-degree 1.

• In C major: B tends to resolve to C.

The chordal seventh (in seventh chords)

In common-practice voice leading, the chordal seventh (the note that forms a seventh above the root) typically resolves down by step.

Example: In G7 (G–B–D–F), the chordal seventh is F, which tends to resolve to E when moving to C major (I).

Why these resolutions exist (a listening-based explanation)

Dissonances feel unstable in tonal style, and the leading tone and chordal seventh often create the strongest instabilities. Stepwise resolution is the smoothest way to relieve that instability.

Example: V7 to I in C major

• V7: G–B–D–F
• I: C–E–G

Typical resolutions:

• B (leading tone) resolves up to C
• F (chordal seventh) resolves down to E

Common misconception: “All chord tones must resolve by step”

Not true. Some chord members (like the fifth of V) can often move more freely. What matters most are:

• Leading tone resolution
• Chordal seventh resolution
• Avoiding objectionable parallels (especially in SATB writing)

Exam Focus

• Typical question patterns:
  • “Complete a progression including V7 to I with correct resolutions.”
  • “Identify non-chord tones vs. chord tones in a cadential context.”
  • “Spot and correct voice-leading errors involving sevenths and leading tones.”
• Common mistakes:
  • Letting the chordal seventh resolve upward or remain unresolved when moving to a stable chord.
  • Doubling the leading tone in part-writing (often creates awkward resolution demands).
  • Forgetting to raise the leading tone in minor, which weakens dominant-to-tonic resolution.

Writing and Voicing Triads and Seventh Chords in Four Parts (SATB Foundations)

AP Music Theory often uses SATB texture (soprano, alto, tenor, bass) to test whether you understand harmony as sound and as voice leading, not just as labels.

Even though an instrument like piano can play close-position chords easily, SATB writing adds constraints: each voice has a comfortable range, voices should move smoothly, and you must avoid certain interval patterns that sound stylistically incorrect in this style.

Doubling rules (practical guidelines)

Because triads have only three notes but SATB has four voices, you usually double one chord member.

Common guidelines:

• In root-position triads, double the root most often.
• In first-inversion triads, doubling is more flexible; doubling the soprano note is common if it is not a leading tone.
• In second-inversion triads, doubling depends on harmonic context (many 6/4 chords behave like embellishments rather than stable harmonies).

For seventh chords, since there are four different chord tones, you usually do not need to double; often each voice gets a different chord member.

Spacing rules (how close voices should be)

In typical SATB style:

• Keep soprano–alto and alto–tenor within an octave.
• Tenor–bass can be more than an octave.

Voice-leading priorities (what to protect first)

When writing chord-to-chord:

1. Resolve tendency tones (leading tone up; chordal seventh down).
2. Keep common tones in the same voice when possible.
3. Prefer stepwise motion; avoid unnecessary leaps.
4. Avoid parallels (especially parallel perfect fifths and octaves between any pair of voices).

Example: simple SATB approach to a I–V7–I in C major

A helpful way to think in layers:

• Bass: C → G → C
• Inner voices: keep common tones when possible; move by step into chord tones
• Soprano: choose a chord tone that allows B→C and F→E resolutions somewhere in the texture

A common mistake is trying to force every voice to re-spell the chord in a brand-new way each time. Smooth part-writing often reuses tones.

What goes wrong most often (and why it matters)

• Parallel fifths/octaves collapse the independence of voices.
• Unresolved sevenths leave dissonance hanging.
• Awkward leaps make lines hard to sing and can cause hidden parallels.

Chords to use when harmonizing (a practical starting point)

When harmonizing melodies or bass lines in a strict tonal style, start with the diatonic chords of the key (the seven triads or seventh chords built on the scale degrees). In minor, be ready to alter scale-degree 7 (and sometimes 6) as needed to create functional dominants such as V and V7, and leading-tone chords such as vii° or vii°7.

Exam Focus

• Typical question patterns:
  • “Write SATB realization of a Roman numeral progression involving triads and seventh chords.”
  • “Complete the missing voices (often alto/tenor) given soprano and bass.”
  • “Identify and correct voice-leading errors in provided part-writing.”
• Common mistakes:
  • Doubling the leading tone (creates resolution problems and weakens the harmony).
  • Treating seventh chords like triads (doubling unnecessarily or failing to resolve the seventh).
  • Violating spacing (especially letting alto–tenor exceed an octave) or crossing voices.

Recognizing and Using Common Seventh Chords in Context (Especially V7 and viiø7)

While many seventh chords exist, AP Music Theory emphasizes the ones that are most functional and most common in tonal syntax.

The dominant seventh chord (V7): the engine of tonal cadences

The V7 chord is powerful because it typically contains:

• The leading tone (scale-degree 7), pulling to tonic
• The chordal seventh, pulling down by step

Together they create strong directed resolution to I.

In a major key, V7 is diatonic and straightforward. In a minor key, V7 almost always uses raised scale-degree 7 (harmonic minor influence), but the chord quality remains a dominant seventh (major triad + minor seventh).

The leading-tone seventh chord (viiø7 in major)

In major keys, the seventh chord built on scale-degree 7 is half-diminished: viiø7. It has strong dominant function because it shares many notes with V7 and contains the leading tone. You’ll often see it in first inversion (viiø6/5), because that voicing smooths the bass line.

Example: C major dominant-function options

• V7: G–B–D–F
• viiø7: B–D–F–A

Both contain B and F (a tendency-tone pair that strongly wants to resolve to C and E). That shared pull is why viiø7 can substitute for V7 in some contexts.

What about fully diminished seventh chords?

In common-practice harmony, fully diminished seventh chords (°7) frequently appear in minor keys when scale-degree 7 is raised and the chord’s seventh is diminished (for example, built on the leading tone of harmonic minor). They are very tense and resolve strongly.

Be careful not to assume every diminished-looking seventh chord is fully diminished. The difference between ø7 and °7 depends on the size of the seventh above the root (minor seventh vs. diminished seventh), and AP-style spelling and labeling expects precision.

Exam Focus

• Typical question patterns:
  • “Analyze a cadence and identify V7 vs. viiø7 roles.”
  • “Spell and resolve V7 in major/minor.”
  • “Identify half-diminished vs. fully diminished seventh chords from notation.”
• Common mistakes:
  • Calling viiø7 in major a fully diminished seventh chord.
  • Forgetting that many viiø7 chords appear in inversion (especially 6/5).
  • Resolving tendency tones incorrectly at cadences (especially in minor).

Applied Understanding: How to Identify Chords Quickly in Real Music

On the AP exam, you’re rarely asked about triads and seventh chords in isolation. More often, you’re reading actual musical textures and must label what’s happening efficiently.

A reliable identification workflow (analysis under time pressure)

When you see a vertical sonority (notes stacked at one moment):

1. Collect pitch names (include accidentals).
2. Reduce to chord tones (ignore obvious non-chord tones if the context makes them clear, but don’t guess recklessly).
3. Stack in thirds mentally to find the root.
4. Determine quality (triad quality, then seventh if present).
5. Map the root to a scale degree in the given key.
6. Determine inversion from the bass note.

This prevents a major trap: trying to name chords by “shape” without checking the key.

Example: quick Roman numeral identification

Key: E♭ major
Sonority notes: A♭, C, E♭, with C in the bass.

• Stack in thirds: A♭–C–E♭ is an A♭ major triad.
• In E♭ major, A♭ is scale-degree 4 → IV.
• Bass is C (the third of A♭ major) → first inversion.
• Label: IV6.

Common “false friends” (sonorities that trick students)

• Incomplete chords: you may see only two or three notes of a seventh chord in the texture. Look for context and tendency tones.
• Second inversion triads: 6/4 sonorities often function as embellishments; don’t automatically label them as stable tonic just because they might be I6/4.
• Minor-key dominants: always check whether scale-degree 7 is raised.

Exam Focus

• Typical question patterns:
  • “Roman numeral analysis of a short chorale-style excerpt.”
  • “Label chords at specific beats; justify inversions by bass notes.”
  • “Identify chord quality and inversion from a reduced score.”
• Common mistakes:
  • Ignoring the key signature and missing necessary raised tones in minor.
  • Misidentifying the root when chords are in inversion.
  • Labeling a sonority without first accounting for non-chord tones in the melody.

Ear Training Connections: Hearing Triads and Seventh Chords

Even though this unit is heavy on written fundamentals, the same concepts are tested aurally. You are training your ear to recognize harmonic “colors” and functions.

Hearing triad quality

Each triad quality has a characteristic sound:

• Major: stable, bright
• Minor: stable but darker
• Diminished: unstable, tense, “compressed”
• Augmented: unsettled, “floating” and symmetrical

A good strategy is to anchor on the third:

• Major triad has a major third above root
• Minor triad has a minor third above root

If you can hear the third accurately, you can identify major vs. minor quickly.

Hearing seventh chords (especially V7)

Seventh chords add a dissonant edge. The dominant seventh in particular has a strong “need to resolve.” Listening for that pull can help you identify it in harmonic dictation.

A practical listening cue: V7 often contains a tritone between its third and seventh (for example, in G7: B and F). That biting interval is a hallmark of dominant tension.

Connecting aural and written skills

If you can sing or audiate the resolution of tendency tones, your part-writing improves automatically. If you feel that scale-degree 7 wants to go to 1, you’re less likely to mishandle it on paper.

Exam Focus

• Typical question patterns:
  • “Identify chord quality (major/minor/diminished/augmented) by ear.”
  • “Recognize V7 in harmonic dictation contexts.”
  • “Track bass motion and infer inversion aurally (especially 6/5 and 4/3 patterns).”
• Common mistakes:
  • Confusing minor and diminished (both can sound dark; diminished is more unstable).
  • Hearing the bass note and assuming it’s the root (inversions are common).
  • Missing the resolution cues that signal dominant function.