Appendix C

[See McAdams (2019) for more detail on perception and acoustic correlates, see Wallmark & Kendall (2018) and Saitis & Weinzierl (2019) for more detail on timbre semantics]

1. bright: Sounds that contain most of their energy in the higher-frequency portion of the spectrum.

2. dark: Sounds that contain most of their energy in the lower-frequency portion of the spectrum.

3. rough: Sounds with sensory dissonance, namely strength in inharmonic partials (e.g., distortion) and/or auditory roughness (i.e., beating)

4. smooth: Sounds with low degree of sensory dissonance, i.e., strength in harmonic partials and/or little or no auditory roughness.

5. muted / damped: Sounds produced by physical systems whose natural modes of vibration have been altered so as to suppress portions of their normal spectral character.

TIMBRE TERMS (ORGANIZATIONAL/PERCEPTUAL)

[See Goodchild & McAdams (2018);Touizrar & McAdams (in press, English version); McAdams, Goodchild & Soden (submitted) for more detail.]

1. grouping / perceptual grouping: Perceptual effects of orchestration practice based on principles of auditory grouping.

concurrent grouping: Concerns the integration or separation of simultaneously present acoustic information from multiple sound sources. This process is responsible for auditory event formation. In orchestration, an "event" can therefore be formed from several grouped sound sources (see fused, blend, timbral augmentation, timbral emergence).
sequential grouping: Involves the grouping of similar things that are occurring over time and separating them from other grouped things occurring over the same time span and that share a different similarity. We can perceptually connect a succession of similar events with shared perceptual qualities and at the same time perceptually connect other event successions with different perceptual qualities such that both successions belong to distinct groups. (see streaming, segregation, stratification, Klangfarbenmelodie)
segmental grouping: Segmentation into perceptual units occurs when discrete changes are involved in one or more musical dimensions; in particular, here, sudden changes in instrumentation or electroacoustic sound create (orchestral) contrasts that delineate sets of different segments in succession, each with their individual identities.

2. auditory scene analysis /

The set of perceptual processes by which the sound world---understood as a “scene" such as is established by objects in a visual field---is organized into events, sequences of events (streams, surface textures), layers of differing degrees of perceptual prominence, and segmented units of various temporal scales.

3. blend /

The fusion of different sources of acoustic information into a more or less unified auditory event. It primarily depends on onset synchrony, harmonicity, and the degree of overlap of constituent sound spectra. It is reinforced over time by parallel or similar motion in pitch and dynamics.

4. fused / perceptual fusion

Perceptual fusion occurs when sounds played by several instruments combine to give the auditory illusion of a single unified sound emanating from a solitary source (see blend).

5. timbral augmentation / augmented (a result of fusion or blend)

The use of a subordinate timbre to embellish or highlight a dominant timbre. One sound source (timbre) is identifiable and dominates the timbral result but is embellished, highlighted or reinforced by one or more other subordinate timbres.

6. timbral emergence / emergent (a result of fusion or blend)

The simultaneous fusion of several constituent timbres, resulting in the formation of a novel timbral complex. Augmentation retains the timbral identity of a particular instrument, whereas emergence eviscerates recognizable instrumental identity, creating a sound for which there is no easily identifiable source.

7. timbral resonance

The use of timbre to highlight and extend pitch classes presented in one instrument by using the sustained timbre of another instrument, much in the same way that a pianist uses the pedal to prolong particular pitches. The resonant part could sustain, fade or swell, sustaining and swelling being impossible on a piano.

8. streaming / musical streams

A stream is a sequence of events produced by a single sound source or groups of blended sound sources, which are perceived as connected and form a unitary musical pattern.

9. Klangfarbenmelodie
Two broad categories:

The Schoenbergian approach deemphasizes individual pitches, melodic voices, and individual instrumental sonorities in favor of homogeneous sonorities. Changes in blended sonorities are foregrounded, while the melodic progression of pitches is either completely neutralized or at the very least relegated to the background of an auditory scene.
The Webernian approach foregrounds the concurrent change in pitch and timbre as co-equal, creating a less nuanced and more direct “tone-color-melody”. Here, both the individuality of instrumental timbre, as well as the progression from one discrete timbre to another become the focal points of ordered changes by step or by degree.

10. segregation / perceptual segregation

Sequences of events that separate into two or more independent streams or strata (orchestral layers) (see stream segregation, stratification). Perceptual segregation occurs because of audible differences in terms of timbre or by differences in register or dynamics, which also have concomitant changes in timbre.

11. stream segregation

Stream segregation is the separation of “voices” or streams of equivalent prominence, a voice being either an individual instrument or two or more instruments that are fused into a “virtual voice” that gives rise to a unique timbre. Note that each stream is integrated but segregated from other streams.

12. stratification into perceptual layers

Orchestral stratification involves looser groupings of events into strata of different prominence (e.g., foreground, middle ground, background). Individual stratified layers can have several instruments that are not fused, but which group together by contrast with the material being played in other layers, including timbral differences. A layer can contain a single voice, two or more co-equal voices in counterpoint, or two or more instruments that, while not blending together, create an integrated surface texture. Unlike the relative equality of layers that characterizes segregation, stratified streams are unequal in prominence and timbre plays a role in determining the perceptual salience that creates the prominence.

13. timbral contrast /
Timbral contrasts form segments as small as melodic-rhythmic patterns and as large as sections of a piece. Contrasts of lesser strength may just highlight changes in other musical parameters and stronger contrasts can create boundaries between adjacent musical materials.

14. masking /
Masking occurs when one sound makes another one inaudible or perceptually softer with potential changes in its timbre.

- submitted by Roger Reynolds

University of California San Diego Research Team