Orchestration is known as the art of combining instruments through various techniques to achieve a particular sonic goal. However, the practice of orchestration has not been studied systematically with the aim of developing a theory of the conditions under which certain orchestration techniques work, and how they are perceived.

The aim of the Orchestration and Perception Project is to develop a psychological foundation for a theory of orchestration practice based on perceptual principles associated with musical timbre. In this ongoing research program, we are studying implicit theory contained within orchestration treatises and orchestral scores. For more information about the larger research program, see our website.

We discovered that many orchestration aims are related to auditory grouping processes (McAdams & Bregman, 1979), which organize the acoustic environment and determine what sounds are grouped together into musical events in concurrent grouping, whether these events are connected into musical streams in sequential grouping, and how listeners chunk event streams into musical units such as motifs, phrases, or themes in segmental grouping (as shown in Figure 1).

Figure 1 - Orchestral effects and auditory grouping processes (McAdams & Goodchild, 2016)

Orchestral effects and auditory grouping processes

Timbre emerges from the perceptual fusion of acoustical components into a single auditory event in concurrent grouping. According to Sandell (1995), the results of instrumental combinations include two types of blend: timbral augmentation (dominant instrument is embellished by subservient instruments) and emergence (synthesizing a new timbre that is identified as none of its constituent instruments). Heterogeneity results when sounds are not blended and separately identifiable.

In sequential grouping, timbre is also involved in auditory stream integration (the perceptual connection of events into a melodic stream) and segregation of events into different streams based on timbral differences that may signal multiple sound sources. We also propose that the interaction of concurrent and sequential grouping results in stratification of musical material into different foreground and background layers of more or less prominence.

Timbre is also implicated in segmental grouping. Discontinuities promote chunking of musical units, called orchestral contrasts with varying orchestration (e.g., antiphonal contrasts, timbral echoes), whereas a succession of gradually changing blended or integrated timbres creates a sense of continuity through progressive orchestration, which would be chunked as one unit (e.g., Klangfarbenmelodie).

Table 1 provides an overview of the orchestral effect categories based on the grouping processes involved. Each description contains a link to a representative example, which contains a detailed view of the annotation, a view of the score, and a sound clip.

Table 1 - Orchestral effects, subtypes, and descriptions arranged by grouping processes
Grouping process Orchestral effect Subtypes and descriptions Analysis Key
Concurrent Blend

Augmentation involves one instrument embellishing another, with one instrument dominating the combination (Sandell, 1995).

Emergence involves synthesizing a new timbre that is identified as none of its constituent instruments (Sandell, 1995).

Heterogeneity involves cases where instruments are doubled at intervals that correspond to the harmonic series (P1, P8, P5, etc.), starting and stopping together and playing in parallel in terms of pitch and dynamics (i.e., they look on the score like they should blend), but they are heard more or less independently.

Punctuation blend occurs when a vertical sonority with several instruments involves a synchronous onset for a single chord, often at a higher dynamic for accentuation. It also is often of fairly short duration so that the listener doesn’t have time to analyze the constituent instruments.

Textural integration occurs when two or more instruments have different material (i.e., contrasting rhythmic figures or pitch material) but integrate to create a single textural layer. It is perceived as being more than a single instrument (i.e., emergence or augmentation), but less than two segregated layers.






Sequential Segregation

Segregation involves clearly distinguishable voices with nearly equivalent prominence or salience. The different instrumental parts must be coequal, often scored as contrapuntal melodic lines with rhythmic independence. Normally segregation occurs with individual instruments, although totally fused instrument pairings or groupings could also constitute a “virtual” voice.


Concurrent/Sequential Stratification

Stratification creates two or more layers of musical material, separated into more and less prominent strands (notions of foreground, middleground, and background). Stratified layers often have more than one instrument in at least one of the layers, which have varying levels of prominence.


Segmental Orchestral contrasts

Antiphonal contrasts sections require call and response type phrase structure, where the response is musically related as a consequence to the call material, but not the same. Each alternating musical unit is scored with different instrumentation.

Timbral echoes involve a repeated musical phrase or idea with different orchestrations. This is distinct from an antiphonal figure, because each group plays the same musical idea (echoing each other), rather than playing an antecedent or consequent phrase; however, one group seems more “distant” than the other.

Timbral shifts can be conceived of as an orchestral “hot potato” or timbral variation, wherein musical materials are reiterated with varying orchestrations (i.e., a repeated phrase is “passed around” the orchestra). Perceptually it is similar to timbral modulation, but is presented in discrete steps, rather than as a seamless coherent grouping.

Sectional boundaries involve changes in timbre, which cause segmentation (chunking) of sequences. Large-scale sections in music are formed on the basis of similarities in register, texture and instrumentation (i.e., timbre). Ergo, timbre change leads to a boundary creation, while timbre similarity leads to chunking of events into coherent units.

General contrasts is currently a “catch all” category, in which timbral changes signal boundary creation, but the specific circumstances do not fall within these categories. Segments annotated as general contrasts will be revisited to discover new categories.






Segmental Progressive orchestration

Klangfarbenmelodie, a technique first explicitly explored by Schoenberg and Webern, is the succession of tone colours, analogous to pitches in a melody (although often accompanied by pitch melody as well). In our conception, it really serves a melodic function and could be considered “timbre melody.”

Timbral modulation involves a succession of gradually changing blended or integrated timbres, which is capable of unifying all the transitional timbres into a coherent grouping [adapted from Schnittke (2006)].


Segmental (contrasts/progressive) Orchestral gestures

Orchestral gestures are large-scale timbral and textural changes that occur in a goal-directed manner, creating a sense of agency and emotional force (Goodchild, 2016). The types are defined by changes in instrumentation in terms of time course (gradual or sudden changes) and direction (additive or reductive changes). The four types relate to the descriptions in the literature of an orchestral crescendo , the reverse process , and timbral contrasts including a rapid switch to full forces and the drop-off to a contrast subgroup or soloist .


Other database parameters

Blend and stratification effects are divided into two temporal categories: static and progressive. Static indicates that the instruments involved in the effect remain fixed, whereas progressive indicates that the instruments vary over time. Therefore, the temporal aspect of static and progressive describes how the orchestration evolves for these concurrent and sequential processes. The progressive category of orchestral effects (i.e., Klangfarbenmelodie and timbral modulation) employs evolving orchestration at its core.

Each effect has a strength rating (1 = weak; 5 = strong), which indicates how strong or weak the effect is perceived to be by our annotators. The factors that contribute to the strength may include the choice of instrumentation, its musical context, or features related to the performance or recording technology.

Note about scores and recordings


Goodchild, M. (2016). Orchestral gestures: Music-theoretical perspectives and emotional responses (PhD dissertation). McGill University, Montreal, Canada.

McAdams, S., & Bregman, A. (1979). Hearing musical streams. Computer Music Journal, 3(1), 26–43.

McAdams, S., & Goodchild, M. (2016). A taxonomy of orchestration devices related to auditory grouping principles. In Preparation.

Sandell, G. J. (1995). Roles for spectral centroid and other factors in determining “blended” instrument pairings in orchestration. Music Perception, 13(2), 209–46.

Schnittke, A. (2006). Timbral relationships and their functional use. In P. Matthews (Ed.), Orchestration: An anthology of writings. New York, NY: Routledge.