Orchestration

In classical music, composers have historically orchestrated their own music. Only gradually over the course of music history did orchestration come to be regarded as a separate compositional art and profession in itself. In modern classical music, composers almost invariably orchestrate their own work. Two notable exceptions to this are Ravel's orchestration of Mussorgsky's solo piano work Pictures at an Exhibition^[1] and Malcolm Arnold's orchestration of William Walton's String Quartet in A minor, producing the latter's Sonata for Strings.^[2]


However, in musical theatre, film music and other commercial media, it is customary to use orchestrators and arrangers to one degree or another, since time constraints and/or the level of training of composers may preclude them orchestrating the music themselves.


The precise role of the orchestrator in film music is highly variable, and depends greatly on the needs and skill set of the particular composer.


In musical theatre, the composer typically writes a piano/vocal score and then hires an arranger or orchestrator to create the instrumental score for the pit orchestra to play.


In jazz big bands, the composer or songwriter may write a lead sheet, which contains the melody and the chords, and then one or more orchestrators or arrangers may "flesh out" these basic musical ideas by creating parts for the saxophones, trumpets, trombones, and the rhythm section (bass, piano/jazz guitar/Hammond organ, drums). But, commonly enough, big band composers have done their own arranging, just like their classical counterparts.

The term orchestration in its specific sense refers to the way instruments are used to portray any musical aspect such as melody, harmony or rhythm. For example, a C major chord is made up of the notes C, E, and G. If the notes are held out the entire duration of a measure, the composer or orchestrator will have to decide what instrument(s) play this chord and in what register. Some instruments, including woodwinds and brass are monophonic and can only play one note of the chord at a time. However, in a full orchestra there are more than one of these instruments, so the composer may choose to outline the chord in its basic form with a group of clarinets or trumpets (with separate instruments each being given one of the three notes of the chord). Other instruments, including the strings, piano, harp, and pitched percussion are polyphonic and may play more than one note at a time. As such, if the orchestrator wishes to have the strings play the C major chord, they could assign the low C to the cellos and basses, the G to the violas, and then a high E to the second violins and an E an octave higher to the first violins. If the orchestrator wishes the chord to be played only by the first and second violins, they could give the second violins a low C and give the first violins a double stop of the notes G (an open string) and E.


Additionally in orchestration, notes may be placed into another register (such as transposed down for the basses), doubled (both in the same and different octaves), and altered with various levels of dynamics. The choice of instruments, registers, and dynamics affect the overall tone color. If the C major chord was orchestrated for the trumpets and trombones playing fortissimo in their upper registers, it would sound very bright; but if the same chord was orchestrated for the cellos and double basses playing sul tasto, doubled by the bassoons and bass clarinet, it might sound heavy and dark.


Note that although the above example discussed orchestrating a chord, a melody or even a single note may be orchestrated in this fashion. Also note that in this specific sense of the word, orchestration is not necessarily limited to an orchestra, as a composer may orchestrate this same C major chord for, say, a woodwind quintet, a string quartet or a concert band. Each different ensemble would enable the orchestrator/composer to create different tone "colours" and timbres.


A melody is also orchestrated. The composer or orchestrator may think of a melody in their head, or while playing the piano or organ. Once they have thought of a melody, they have to decide which instrument (or instruments) will play the melody. One widely used approach for a melody is to assign it to the first violins. When the first violins play a melody, the composer can have the second violins double the melody an octave below, or have the second violins play a harmony part (often in thirds and sixths). Sometimes, for a forceful effect, a composer will indicate in the score that all of the strings (violins, violas, cellos, and double basses) will play the melody in unison, at the same time. Typically, even though the instruments are playing the same note names, the violins will play very high-register notes, the violas and cellos will play lower-register notes, and the double basses will play the deepest, lowest pitches.


As well, the woodwinds and brass instruments can effectively carry a melody, depending on the effect the orchestrator desires. The trumpets can perform a melody in a powerful, high register. Alternatively, if the trombones play a melody, the pitch will likely be lower than the trumpet, and the tone will be heavier, which may change the musical effect that is created. While the cellos are often given an accompaniment role in orchestration, there are notable cases where the cellos have been assigned the melody. In even more rare cases, the double bass section (or principal bass) may be given a melody, like, the high-register double bass solo in Prokofiev's Lieutenant Kije Suite.


While assigning a melody to a particular section, such as the string section or the woodwinds will work well, as the stringed instruments and all the woodwinds blend together well, some orchestrators give the melody to one section and then have the melody doubled by a different section or an instrument from a different section. For example, a melody played by the first violins could be doubled by the glockenspiel, which would add a sparkling, chime-like colour to the melody. Alternatively, a melody played by the piccolos could be doubled by the celesta, which would add a bright tone to the sound.


In the 20th and 21st century, contemporary composers began to incorporate electric and electronic instruments into the orchestra, such as the electric guitar played through a guitar amplifier, the electric bass played through a bass amplifier, the Theremin and the synthesizer. The addition of these new instruments gave orchestrators new options for creating tonal colours in their orchestration. For example, in the late 20th century and onwards, an orchestrator could have a melody played by the first violins doubled by a futuristic-sounding synthesizer or a theremin to create an unusual effect.


Orchestral instrumentation is denoted by an abbreviated formulaic convention,^[3] as follows: flute, oboe, clarinet, bassoon, horn, trumpet, trombone, tuba. More details can be contained in brackets. A dot separates one player from another, a slash indicates doubling. Timpani and percussion are denoted 2Tmp+ number of percussion.


For example, 3[1.2.3/pic] 2[1.Eh] 3[1.2.3/Ebcl/bcl] 3[1.2/cbn.cbn] tmp+2 is interpreted as:


As an example, Mahler Symphony 2 is scored: 4[1/pic.2/pic.3/pic.4/pic] 4[1.2.3/Eh.4/Eh] 5[1.2.3/bcl.4/Ebcl2.Ebcl] 4[1.2.3.4/cbn]- 10 8 4 1- 2tmp+4-2 hp- org- str.