In addition to duration, pitch, dynamics and expressive techniques, tone colour, texture and structure, the HSC exam may also ask students about compositional devices, the development, treatment or use of a musical idea, interest, roles of instruments and the relationship between them, tension, unity, contrast, and more.
I have labelled these "metaconcepts" as I believe they are concepts about concepts.
For example, tension may be achieved through the use of pitch, dynamics, expressive techniques, and tone colour. Roles can be described with an exploration of texture, pitch, and duration.
Unity and contrast are inherent aspects of every composition. These terms describe the similarities and changes that occur throughout a work:
Unity (or balance) - Elements of a composition that repeat, stay similar, or reoccur throughout. This may include motifs and musical ideas, a specific rhythmic device, tonal centre, instrumentation, etc.
Contrast (or variety) - Any changes that occur throughout a composition. This could be the transformation or development of a motif, introduction of new musical material, modulation to a new key, etc.
An effective composition will always have a good mix of unity and contrast. Too much unity can result in a composition that feels too repetitive; one that doesn't develop or "go anywhere". A piece like this is likely to become boring very quickly. On the other hand, too much contrast can create a sense that nothing in the piece relates to anything else. Each bar, phrase, or section may sound totally different to the ones around it and this may be overwhelming and confusing to listen to.
Explore how contrast is achieved in this excerpt.
Explain how unity and contrast are achieved in this excerpt. In your answer, 4 make specific reference to the score.
How is balance created in this excerpt? In your answer, make reference to the score.
Explain how variety is achieved in this excerpt. In your answer, make specific reference to the score.
Unity and contrast are
Compositional devices are ways in which motifs and musical ideas can be used and developed throughout a piece. By using a limited number of motifs and compositional devices, composers can establish an effective sense of unity and contrast in their works.
Compositional devices include, but are not limited to:
Retrograde
Fragmentation
Interpolation
Extension
Repetition
Ostinato (or riff)
Rhythmic drive
Unison
Rhythmic unison
Call and response
Rhythmic augmentation
Rhythmic diminution
Rhythmic alteration
Hemiola
Syncopation
Polyrhythm
Cross-rhythm
Additive rhythm (or additive metre)
Irrational rhythm
Mixed metre
Interval expansion (or interval augmentation)
Interval contraction (or interval diminution)
Pitch displacement
Octave displacement
Inversion
Sequence
Imitation
Transposition
Round or canon
Countermelody
Passing notes (and other non-chord tones)
Dovetailing
Hocketing
Pedal point (or drone)
Figured bass
Basso continuo
Alberti bass
Parallel motion
Contrary motion
Similar motion
Oblique motion
Suspension
Extended chords
Cadence
Tone cluster
Modulation
Reharmonisation
Development, treatment, or use directly relates to compositional devices