Music Theory, Composition, and Arranging
Domain 2 tests functional harmony, voice leading, transposition, and practical scoring for school ensembles.
Core rules
- Key signatures follow the circle of fifths: sharps enter F–C–G–D–A–E–B; flats enter B–E–A–D–G–C–F.
- Build triads in thirds. Root position has the root in the bass; first inversion, the third; second inversion, the fifth. Figured bass is 5/3, 6, and 6/4.
- In four-part writing, keep common tones, move the bass by step or fourth/fifth, resolve the leading tone up, and avoid parallel perfect fifths and octaves.
- Transpose by the interval an instrument sounds below concert pitch: Bb instruments sound a major second lower; F instruments a perfect fifth lower; Eb alto sax a major sixth lower; Eb clarinet a minor third higher.
- Compose with clear 2- or 4-bar motives, sequences, and cadences. Arrange by idiomatic range, balance, and doubling rather than by filling every staff.
Worked example
A concert melody in Bb major begins on F4. For Bb clarinet, write G4: the clarinet sounds a major second lower, so written G4 produces concert F4. For F horn, write C5: the horn sounds a perfect fifth lower, so written C5 produces concert F4. The written key for clarinet is C major; for horn, F major. Reasoning: transpose the key and melody up by the interval the instrument sounds down; then verify one pitch by sounding it back.
Traps
- Transposing in the wrong direction or changing the melody but not the key signature.
- Labeling inversion by the melody note instead of the bass.
- Writing for concert-pitch ranges when beginners need written ranges.
- Over-doubling the third in root-position chords and creating a heavy, out-of-tune sonority.
- Using parallel fifths between outer voices in a chorale-style exercise.