Music Theory and Harmony
Music Theory and Harmony
This domain tests fast, accurate labelling: intervals, scales and modes, chord spelling, figured bass, Roman-numeral analysis, cadences and short modulations. Items are short but unforgiving - one wrong accidental or inversion figure usually voids the whole answer - so examiners reward a fixed checking routine rather than speed.
Intervals, scales, modes
- Count interval quality from the letter names first: F–B is an augmented fourth, F–C♭ a diminished fifth. Same sound, different spelling, different mark.
- Harmonic minor raises the 7th both ascending and descending; melodic minor raises 6 and 7 ascending and restores both descending. Questions almost always test the descending melodic form.
- Modal fingerprints: Dorian = minor with raised 6; Phrygian = minor with ♭2; Lydian = major with ♯4; Mixolydian = major with ♭7; Locrian = minor with ♭2 and ♭5.
Chords, inversions, figured bass
- Triads: 5/3, 6, 6/4. Sevenths: 7, 6/5, 4/3, 4/2.
- In a major key the diatonic sevenths are Imaj7, ii7, iii7, IVmaj7, V7, vi7, viiø7; in harmonic minor, vii°7.
- The inversion is fixed by the lowest sounding note, not by the right hand's bass line.
Cadences
- Perfect authentic: V–I, both root position, soprano on the tonic. Imperfect authentic: same harmony but a chord inverted or the soprano on 3 or 5.
- Interrupted (deceptive): V–vi, or V–VI in minor. Plagal: IV–I. Phrygian half cadence in minor: iv6–V.
Worked example
You are given the chord G–B♮–D–F and told the key is C minor. Three flats in the signature make B♮ chromatic; the only diatonic reason for a raised B in C minor is the leading tone of the harmonic scale. The root is G, scale degree 5; the structure is a major triad plus minor seventh. So the chord is V7 in root position, resolving to i (C–E♭–G), with the seventh F falling by step to E♭. The same chord inside E♭ major has no diatonic function and must be labelled V7/vi.
Traps that cost marks
- Parallel fifths or octaves between any pair of voices, including outer parts by contrary motion (hidden fifths with a leaping soprano).
- Doubling the leading tone, or resolving a seventh upwards.
- Accidentals last to the end of the bar and only in that octave; candidates forget both halves of the rule.
- Labelling by chord shape instead of scale degree: a first-inversion tonic (6/3) is not a cadential 6/4.