This approach to orchestration analysis is based on a taxonomy of orchestral grouping effects derived from principles of auditory scene analysis (McAdams, Goodchild & Soden, 2022). The basic premise is that fundamental processes of auditory grouping tacitly or explicitly underlie many orchestration decisions, structuring music through the selection, combination and juxtaposition of musical qualities to achieve a desired sonic result. The taxonomy has three main classes of effects related to different auditory grouping processes.

Functional orchestration has basically four objectives: i. Isolation and verbalization of universal principles on the composition of timbres. ii. Development of general functions to categorize different operations on timbre. iii. Extension of the understanding of the instrumentation. iv. Identification, categorization and improvement of these instrumental functions and their mechanisms in relationship with their perceptual effects.

A metatimbre is a collection of timbres presenting a strong perceptual similarity. They come at least from two different instruments within a family or ACROSS families. The sounds belonging to the same metatimbre class (metClass) have the same perceptual function and can be potentially exchanged without altering their salient timbral characteristics (they are interchangeable within an orchestration).