Definition
A reduction turns a large score (orchestra, choir with orchestra, big band) into a version for fewer instruments, preserving its musical essence. The main forms:
- piano reduction: the orchestra condensed onto two staves;
- vocal score (voice and piano reduction): the vocal parts stay complete, the orchestra becomes piano (used for opera and choir rehearsals);
- short score / sketch (condensed score): 4–8 staves with the main parts, used by film composers and orchestrators to hand off work;
- ensemble reduction: a symphonic piece adapted for 5–15 instruments.
Historical examples: Franz Liszt's piano transcriptions of Beethoven's symphonies; the chamber reductions made for Schoenberg's Society for Private Musical Performances in Vienna (1918–1921).
Principles
- Hierarchy: melody first, then bass, then the essential inner parts (the third and seventh of the chord), and finally the details.
- Eliminate doublings: the orchestra's octaves and unisons are reduced to a single line (or to an octave in the left hand for weight).
- Playability: each hand covers at most a ninth or a tenth; no more than 4–5 notes per hand.
- Translate techniques: string tremolo → repeated chords or piano tremolo; long wind notes → repeated or arpeggiated notes (the piano doesn't sustain); pizzicato → staccato; timpani rolls → low tremolo.
- Register: shift parts by an octave if necessary to fit under the hands, keeping the contour.
Procedure for a piano reduction
- 1. Identify the melody and bass in each bar and write them down.
- 2. Analyze the harmony and add the inner notes in the right or left hand.
- 3. Choose the most characteristic accompaniment figures (an ostinato, a rhythm) and keep at least a trace of one.
- 4. Mark in small notes (cue notes) the important lines that cannot be played, with the name of the instrument.
- 5. Indicate the original orchestration (“Strings”, “Brass”, “Fl.”) to help both players and conductors.
Short scores for film and production
In film, the composer often hands the orchestrator a sketch of 6–8 staves with indications (e.g. “Hn melody”, “Str tremolo”), or a MIDI mockup from which the orchestrator derives the score. In modern production the sketch is often the DAW project itself, with tracks grouped by family.
Ensemble reduction
Example: from symphony orchestra to 8 instruments (flute, clarinet, horn, violin I, violin II, viola, cello, piano).
- Melody: violin I or flute.
- Typical woodwind doublings: a single woodwind per color.
- Brass: the horn carries the sustained notes; the piano provides the brass accents.
- Bass: cello and the piano's left hand.
- Percussion: given to the piano (low chords) or eliminated.
Reductions in pop and live arranging
Reducing a song produced for a live band is the same problem: 60 studio tracks become 4–6 musicians. You decide who plays the hook, who plays the harmony, what goes on sequence (backing track), what gets cut. Piano-and-vocal versions of pop songs are also reductions.
Common mistakes
- Trying to keep everything: the reduction becomes unplayable.
- Losing the characteristic rhythm (removing an ostinato changes the character of the piece).
- Neglecting inner voices: without thirds and sevenths the harmony empties out.
Practice exercise
Take 16 bars of an orchestral score (e.g. from IMSLP: the theme of the Largo from Dvořák's Symphony No. 9). Write a two-hand piano reduction following the procedure, then a reduction for string quartet and piano. Compare which line you had to drop in each version.
Links
Reading an Orchestral Score, Orchestration: Families, Ranges and Blends, Piano Accompaniment Patterns, Orchestration with Virtual Libraries in the DAW.