Theory of Western Music: notation, scales, intervals, chords and harmony
Domain focus
The Theory paper tests how precisely you read and manipulate Western notation. It asks you to identify clefs, note values, key signatures, scales, intervals, triads and cadences, and to explain harmonic movement rather than merely label chords.
Core rules
- A major scale follows TTSTTTS; natural minor uses TSTTSTT. Harmonic minor raises 7; melodic minor raises 6 and 7 ascending.
- Key signatures follow the circle of fifths: one sharp = G major/E minor; one flat = F major/D minor. Relative minors share the signature; parallel minors share the tonic.
- Interval quality depends on the major-scale reference: E–B is a perfect fifth; E–B-flat is diminished. Invert an interval by subtracting from 9 and reversing quality; perfect stays perfect.
- Triads are stacked thirds. Inversions use figured bass: root position 5/3, first inversion 6, second 6/4. A dominant seventh resolves to tonic, with the leading tone rising and the seventh falling.
Worked example
In B-flat major, build the dominant seventh and resolve it. The dominant is F; the diatonic seventh chord on F is F–A–C–E-flat. It resolves to B-flat–D–F. A rises to B-flat; E-flat falls to D. If the chord is inverted, the same tendency tones still resolve.
Traps
Mixing relative and parallel minor; forgetting that an accidental changes interval quality; doubling the leading tone; writing parallel fifths in a four-part exercise; treating 6/4 as a root-position chord.