Ravel in the context of "Paris Conservatoire"

Orchestration is the study or practice of writing music for an orchestra (or, more loosely, for any musical ensemble, such as a concert band) or of adapting music composed for another medium for an orchestra. Also called "instrumentation", orchestration is the assignment of different instruments to play the different parts (e.g., melody, bassline, etc.) of a musical work. For example, a work for solo piano could be adapted and orchestrated so that an orchestra could perform the piece, or a concert band piece could be orchestrated for a symphony orchestra.

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 and Malcolm Arnold's orchestration of William Walton's String Quartet in A minor, producing the latter's Sonata for Strings.

A riff is a short, repeated motif or figure in the melody or accompaniment of a musical composition. Riffs are most often found in various genres of rock music (including punk and heavy metal music), as well as Latin, funk, and jazz, although classical music is also sometimes based on a riff, as in Ravel's Boléro. Riffs can be as simple as a tenor saxophone honking a simple, catchy rhythmic figure, or as complex as the riff-based variations in the head arrangements played by the Count Basie Orchestra.

David Brackett (1999) defines riffs as "short melodic phrases", while Richard Middleton (1999) defines them as "short rhythmic, melodic, or harmonic figures repeated to form a structural framework". Author Rikky Rooksby states: "A riff is a short, repeated, memorable musical phrase, often pitched low on the guitar, which focuses much of the energy and excitement of a rock song."