Timbre Semantic Associations Vary both Between and Within Instruments
Timbre Semantic Associations Vary both Between and Within Instruments
An Empirical Study Incorporating Register and Pitch Height
Published: February 17, 2025
Annie Liu (Princeton University)
Editor’s note: this report summarizes an article published in Music Perception. See Reymore et al. (2023) in the works cited below for further information.
Introduction
In this study, the authors aimed to fill a crucial gap in timbre research regarding the variation and range in timbre within an instrument and its corresponding semantic associations. These variations depend on dynamics, pitch, articulation, duration, vibrato, technique, and other parameters. Register-dependent descriptions of instruments’ timbres characterize instruments based on register, or a part of the instrument’s range, such as the rumbling, thick, and muddy low notes of the piano versus the tinkling, thin, and clear highest notes. This relationship is further complicated by the varying tessituras, or range of playable notes, for different instruments (for example, the flute’s lowest notes overlap with the bassoon’s highest notes, as shown below).
To address this gap, the authors conducted a study examining the effect of register on instrumental timbre semantics, with additional analysis relating specifically to pitch height. Drawing on past research relating to timbre and pitch or register, the authors chose to represent each of the eight orchestral instruments with a low, middle, and high note relative to that instrument’s range, using two pitch classes (C and G). The instruments (shown below) were selected based on the ACTOR CORE Project’s ensemble of violin, bass clarinet, trombone, and vibraphone; the remaining four instruments included were flute, oboe, trumpet, and cello.
Click to listen to the high, middle, and low stimuli for these instruments:
Violin
Oboe
Trumpet
Bass Clarinet
Vibraphone
The authors recruited 540 participants online who listened to the 3 notes from each of the eight instruments (24 total notes). The participants rated each note based on 20 semantic descriptors for timbre from Reymore and Huron (2020), shown below, according to how well the descriptor described the sound being played.
Timbre Semantic Descriptors
Deep, thick, heavy
Shrill, harsh, noisy
Raspy, grainy, gravelly
Resonant, vibrant
Sustained, even
Smooth, singing, sweet
Percussive (sharp beginning)
Ringing, long decay
Hollow
Open
Project, commanding, powerful
Pure, clear, clean
Sparkling, brilliant, bright
Woody
Focused, compact
Nasal, buzzy, pinched
Brassy, metallic
Airy, breathy
Muted, veiled
Watery, fluid
Results and Analysis
For certain sets of terms, the results showed similar patterns across registers for all the instruments (for example, deep/thick/heavy was consistently rated highest in the low register, whereas sparkling/brilliant/bright received the highest ratings in the high register). For other terms, relationships between register and semantic associations depended on the instrument, for example, the trombone was rated most smooth/singing/sweet in its higher register, whereas the trumpet received increased ratings for smooth/singing/sweet in its middle register. There was little variance among registers for the descriptors brassy/metallic and sustained/even across all the instruments. Unlike the other instruments, the vibraphone displayed very little semantic variation across registers.
The authors analyzed the data in several ways, including an exploratory correlation matrix to determine how independent the 20 semantic categories were from one another, finding similar results as found in Reymore (2021), and hierarchical clustering, to show relationships among stimuli within the 20 semantic categories. These clusters did not seem to depend on instrument, instrument family, or Hornbostel-Sachs categories for organology; rather, they are better interpreted using pitch height, with “a high cluster (G5–C7), a medium-high cluster (C5–G5), a medium-low cluster (G3–G4), and a low cluster (C2),” which indicates “the trend for semantic groupings to correspond with pitch height” (Reymore et al. 2023, 264).
The authors generated statistical models and found that register and instrument played significant roles for most models, though not for brassy/metallic. Some variables only indicated statistically significant main effects for one of those (register was significant for open, but not instrument, and register was not significant for focused/compact, nasal/buzzy/pinched, and sustained/even, but instrument was). However, the authors also wanted to distinguish between register and pitch height for these models. They modeled pitch height as a categorical variable, which produced significantly better goodness-of-fit than models with only register, thus explaining more variance in semantic ratings.
Discussion and Conclusion
With these findings, the authors confirmed some differences in semantic category ratings within instrument ranges and between different instruments. Register only accounted for 5% or more of the variance for only 8 of the 20 categories, a relatively small impact. Interestingly, bass clarinet and trombone showed increased average ratings for smooth/singing/sweet in their higher register, whereas flute, oboe, trumpet, violin, and cello displayed highest average ratings for smooth/singing/sweet in their middle register. Seeing as brassy/metallic ratings had little variation across the stimuli, it is possible that since the majority of participants were nonmusicians, their variable knowledge of the terms brassy/metallic may have influenced those ratings. This opens up an avenue for future research on how musicians and nonmusicians potentially apply semantic terms to timbre differently, and how music training impacts timbre description.
Future research could also expand this study to other instruments and thus a broader range of musical timbres. Some findings from this study fit the descriptors of instrumental timbre in orchestration treatises, like smooth/singing/sweet and airy/breathy for the flute, however, many diverge considerably (Wallmark 2019a). Once again, this could be due to differences in musical training, since treatises are written by professional musicians, and the participants were mostly nonmusicians and amateur musicians. Instrumental recognition and prior knowledge of instruments could also affect ratings.
This work contributes to the broader study of timbre semantics and can be applied by composers, orchestrators, and music analysts, particularly when considering instruments and register. These results could also assist in further understanding metatimbres (Soden, 2020), which are “collections of timbres related by shared attributes…that may lead them to be grouped perceptually and semantically,” whether by pitch, attack, or other attributes (Reymore et al. 2023, 271).
Works Cited
Reymore, L., & Huron, D. (2020). Using auditory imagery tasks to map the cognitive linguistic dimensions of musical instrument timbre qualia. Psychomusicology, 30(3), 124–144. https://doi.org/10.1037/pmu0000263.
Reymore, L., Noble, J., Saitis, C., Traube, C., & Wallmark, Z. (2023). Timbre semantic associations vary both between and within instruments: An empirical study incorporating register and pitch height. Music Perception 40(3), 253–274. https://doi.org/10.1525/mp.2023.40.3.253
Soden, K. (2020). Orchestrational combinations and transformations in operatic and symphonic music. [Doctoral dissertation]. McGill University.
Wallmark, Z. (2019). A corpus analysis of timbre semantics in orchestration treatises. Psychology of Music, 47(4), 585–605. https://doi.org/10.1177/0305735618768102