The Taxonomy of Orchestral Grouping Effects Applied to Ravel’s Alborada del gracioso for orchestra

Text

Jul 7

Written By Stephen McAdams and Kit Soden

A Timbral and Orchestrational Pluralistic Analysis

The Taxonomy of Orchestral Grouping Effects Applied to Ravel’s Alborada del gracioso for orchestra

by Stephen McAdams & Kit Soden
Timbre and Orchestration Resource | Modules | Taxonomies of Orchestration

Introduction

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.

Concurrent Grouping

Concurrent grouping processes result in blended combinations of instruments or their perceptual separation. What is perceived as timbre depends on which acoustic information gets fused into a perceptual event on the basis of onset synchrony, harmonicity, and parallel change in pitch and dynamics. So orchestrating blend with these cues can create timbral augmentations of one instrument or instrument family by other embellishing instruments or completely new emergent timbres that do not resemble their constituents. However, concurrent grouping also depends on timbral similarity among constituent instruments and they may respect the rules of synchrony, harmonicity and parallelism and still not blend, in which case the effect is termed timbral heterogeneity.

Sequential Grouping

Sequential grouping processes result in the perceptual formation of melodic lines, the integration of surface textures, and the segregation of melodies or stratified (foreground and background) layers on the basis of acoustic (dis)similarities. In stream integration, consistent timbre, register, and dynamics across a sequence of events helps them to be connected perceptually into an auditory stream. The events may be played by a single instrument or a blended group of instruments. The integration into a surface texture occurs when two or more instruments have contrasting rhythmic figures and/or pitch material but are integrated perceptually over time, being perceived as a looser grouping of more than one instrument, although the instruments do not clearly separate into distinguishable and trackable streams. Acoustic discontinuities trigger the segregation of single or blended instruments either into multiple streams or equal prominence, as in much contrapuntal writing, or into different orchestral strata with differing salience—foreground being more salient that middleground, which is more salient than background.

Segmental Grouping

Segmental grouping processes contrast sequentially presented blocks of materials and contribute to the creation of perceptual boundaries based again on acoustic discontinuities. Events of similar properties in a sequence are grouped together, and a sudden change in one or more of these properties, followed by a timespan with events having similar properties among themselves, introduces a contrast that provokes segmentation. Temporal discontinuities include silent gaps and changes in articulation, duration and tempo. Qualitative discontinuities include those in pitch, dynamics, timbre, and surface texture. There are different varieties of timbral contrasts in the taxonomy. Timbral shifts involve a passage in which a musical pattern defined by melody and rhythm is passed in similar form from instrument to instrument, often with accompanying pitch and harmonic change. The repetition of exact musical material with an instrumentation change that simulates change of perceived distance is termed timbral echo. Antiphonal contrasts are achieved by the alternation of different instrumentations and orchestral registers in a call-and-response-type format oftentimes with accompanying harmonic material and different musical material alternating between call and response. Timbral juxtapositions involve moments where a change in orchestration is introduced to enhance a discursive or structural moment at a local level for contrasts that do not fit into the other three categories, and which can introduce melodic, rhythmic, and harmonic changes as well.

Analysis based on this taxonomy—and formalized in the orchestration analysis platform OrchView and the Orchestration Analysis and Research Database (OrchARD)—involves a joint auditory and visual (score-based) approach. Decisions about what blends or not, what instrumental parts integrate or segregate into streams, surface textures and layers, and where contrasts occur are based on listening to and aurally analyzing a particular recording and then using the visual representation of the annotated score to formalize that perception. In this specific analysis of three passages in Maurice Ravel’s Alborada des gracioso, the 1981 recording by Charles Dutoit conducting the Montreal Symphony Orchestra was used as a reference (Decca 410 010-2, 1982,1983).

Analysis
mm. 1–11

The opening passage of Alborada del gracioso (Figure 1) starts with a rhythmic hocketing between unison harp, first violins, and half of the violas on the one hand and second violins and the other half of the violas in chords on the other hand, all playing pizzicato. This pattern represents a transforming integration into a rhythmic surface texture of these strings, the integration of which is ensured by the plucked string timbre. At m. 6, the harp, first violins and violas leave the pattern as cello joins. Then contrabasses join in m. 7, followed by the addition in m. 10 of the violas that had previously left. The second violins and contrabasses drop out in m. 11. This progressive addition and subtraction of instruments creates an initial thinning of the texture to allow the foreground material to emerge with a progressive intensification and then dénouement of the orchestral texture over the rest of the passage.

As of m. 6, this pattern becomes the background layer of a two-layer stratification that lasts until the downbeat of m. 9. The foreground layer has a descending melodic motif in regular eighth notes that is repeated once, which is borne by a timbral blend with a dominating string timbre (first violins and half of the violas) augmented in timbral richness by two staccato bassoons and two harps, all in unison. This melodic passage then gives way again in m. 9 to the timbrally transforming rhythmic texture through m. 11. The clearly identifiable descending melody is more salient in the foreground against the rhythmic reduction of the background pattern in these measures, essentially accenting the downbeat and the second and fifth notes of the 6/8 melody.

Summary:

Transforming integrated surface texture becoming a Stratification (foreground: Blend, background: Integration)

mm. 44–58

This passage contains a large-scale timbral juxtaposition, contrasting the timbres and textures in the foreground layer of mm. 44-52 with those in the foreground in mm. 53-58 (Figure 2). In particular, the rapid 16th-note triplets at constant pitch in the brass are subsequently contrasted with the same rhythmic pattern in flute and harp, but now carrying melodic material. Each of the two contrasting regions have stratification into foreground and background layers, with brief appearances of a middleground in mm. 45 and 47. The background is similar in both regions with an emergent timbral blend involving pizzicato divisi strings in interlocking rhythmic patterns at the 8th-note level across the different string sections. An orchestral gesture originating in this background in m. 47 with the gradual addition of more string forces moving up in register reaches a climax with additional reinforcement by the woodwinds in m. 50. This orchestral gesture also involves a transforming integrated stream starting with first trumpet in m. 48 playing a rapid 16th-note triplet rhythm, joined in unison by second trumpet in m. 49 and then the addition of horns 1-3, also in unison, at the climax of the gesture. This stream continues beyond this local climax with a gradual reduction to three stopped horns and then just second horn in m. 52, leading to the transition to flute and harp at the boundary of the call of the timbral juxtaposition at m. 53.

The foreground in the first region first displays an antiphonal contrast between rapid 16th-note rhythm in trumpet and a flourish with flute augmented by harp. The trumpet enters again and the next time the flourish has flutes and harps in octaves, intensifying the response. During these flourishes, horns 1 and 3 occupy a middle ground with a raucous sustained major 2nd that resolves to a unison when the trumpet enters again. In the second region, the foreground is a more delicate, but still rapid rhythmic passage played by flute, again augmented by harp.

Summary:

44-58—Timbral Juxtaposition
44-53—Stratification
- Foreground: Antiphonal Contrast
  - Timbral Augmentation, Timbral Augmentation, Transforming Stream)
- Middleground: Timbral Emergence, Timbral Emergence;
- Background: Timbral Emergence
53-58—Stratifications (FG: Timbral Augmentation, BG: Timbral Emergence)

mm. 72–105

This passage involves a series of timbral juxtapositions between a lyrical solo bassoon and a complex, stratified orchestral texture with rhythmic material in the foreground (first, second, third, fourth iterations) and more sustained harmonic material in the background (Figure 3). The background harmony (first, second, third, fourth iterations) on tightly voiced chords in thirds and seconds in the low to middle register is carried by part of the divisi strings (3 Vn1, 3 Vn2, 3 Va, 3 Vc, 2 Cb). Against this sustained sonority is the rhythmic material in the foreground formed of isochronous rhythms, again on tightly voiced chords in thirds and seconds in the rest of the divisi strings (3 Vn1, 3 Vn2, 2 Va1, Vc, 1 Cb) playing pizzicato, the two harps and percussion (xylophone, snare and suspended cymbal). However, theses chords are in the middle to high register. The plucked strings and xylophone create an emergent timbral blend (first, second, third, fourth iterations), but the snare and cymbal are heterogeneous (first, second, third, fourth iterations) due to their noisy, inharmonic, unpitched timbres. At certain points, the arpeggiation of the first harp stands out as well due to its asynchrony with the other plucked strings. The rhythmic pattern, higher register and heterogeneity make this layer more salient.