Icicle — Robert Aitken
Icicle — Robert Aitken
Amazing Moments in Timbre | Timbre and Orchestration Writings
by Kelsey Lussier
Icicle (1977) for solo flute, by Canadian composer, conductor, and flautist Robert Aitken, captures a quintessentially winter soundscape with its highly variable timbral palette. Audible right from the beginning of Nina Assimakopoulos’s 2021 recording, Icicle is saturated with timbres that evoke such cold, wintry imagery as glistening icicles and blowing snow. The wintry timbres in Icicle are created by various extended playing techniques. For instance, Aitken includes techniques such as (but not limited to) timbral trills (Figure 1a, Audio Example 1a), pitch bends and glissandi (Figure 1b, Audio Example 1b), flutter tonguing (Figure 1c, Audio Example 1c), multiphonics (Figure 1d, Audio Example 1d). These techniques deviate from standard concert techniques in the Western Art Music tradition, diverging especially from those that produce a clear sound with an obvious fundamental pitch.
Figure 1a–d: Score excerpts showing techniques that create icey timbres. The bottom staff shows performance instructions, and the top staff represents the sounding results. When the top staff is empty, the bottom staff adequately summarizes the sound.
Aitken’s version of the timbral trill, which he names the “coloured trill,” is one of the most frequently used techniques that contributes “simmering, glistening [timbral] effects” (Aitken, 1977) to this piece. The coloured trill is most often realized by the motive pictured in Figure 2 (hereafter: the icicle motive). In general, timbral trills involve trilling between two different fingerings for the same pitch, usually one standard fingering and one alternate. The timbre of that pitch varies with each fingering, often the result of contrasting overtone structures or microtonal inflections of the note being trilled. Similarly, Aitken’s coloured trill uses multiple alternate fingerings of the note C5 to transform the timbre of this note over the course of the icicle motive. The icicle motive technique therefore combines a regular tril (i.e., neighbour motion between C5 and C#5, as shown on the top staff of Figure 2 and Audio Example 2) and a timbral trill by progressively varying the time of C5 before the arrival of C#5. To execute the coloured trill, Aitken asks the performer to play without pressing the primary thumb key. Closing this thumb key is essential for producing most pitches on the flute. When left open, the performer’s air escapes the instrument relatively early, reducing the number of available pitch classes to C5 and C#5 : C#5 is normally played without pressing any keys on the flute and C5 is played by pressing only the key beneath the left index finger. Closing the other finger keys in succession without closing the thumb gradually modifies the timbre of the note C5 by modifying its acoustic structure with each new fingering.
Interestingly, Aitken admits that the inspiration for this motive was not wintry in the least. Although Aitken composed Icicle while he was visiting New Hampshire in the winter and titled it after some icicles he saw out his window, Aitken (2020) reveals that the icicle motive was inspired by the Pink Panther theme and that he intended the coloured trill to be a “fun and out-of-the-ordinary trick” (Cook 2016 paraphrasing Aitken 1981). Nevertheless, on my hearing, the coloured trill’s timbre strongly evokes images of glistening icicles on a cold winter’s day.
Figure 2: Annotated score of Icicle (1977) showing versions 1 and 2 of the icicle motive with its coloured trill technique, audible in Audio Example 2.
Extended techniques such as the coloured trill are so ubiquitous in Icicle that they occur in 79 out of its 85 total measures (93%), leaving only 6 measures of music played with standard Western Classical flute technique. This saturation of extended techniques, including those shown in Figures1a–d, both showcases the flute’s widely varied timbral palette and creates a blustery winter soundscape that matches the piece’s evocative title.
In her 2013 article, flautist and scholar Marie-Hélène Breault develops a hot/cold axis for describing timbres in Icicle, associating those created by extended techniques with the cold, and standard flute technique with heat/warmth (21–22). She explains that this abstract binary opposition can exist because timbres played with extended techniques sound cold in context only. That is, they sound cold because they are starkly different from those that are played with typical flute technique, which tend to sound more full, focused, and warm. She describes the differences between cold and warm sounds from two perspectives: that of playing the techniques, and that of perceiving them as a flutist. Concerning sound-production, Breault explains that effects produced with alternative fingerings (i.e., extended techniques) often cause a brief delay in the start of the sound that is not present when flutists play the same note(s) with conventional fingerings. Moreover, she describes the pitch of sounds created with such extended techniques/alternative fingerings as extremely “decentralized,” which refers to an increased audibility of (un-pitched) breath in the tone. She suggests that this decentralization imparts a sense of fragility, frailty, and hollowness to the tone, making it sound as though it could break (21–22). Indeed, these techniques require extremely precise embouchure position, air pressure, air direction, and aperture size to be played; if one of these elements is incorrectly executed, the sound will truly “break,” resulting in an unintended tone or register. Breault suggests that this fragility and transparency evokes the image of crystal and explicitly associates it with the cold. From the perceptual perspective, she suggests that flutists often associate “warmth” in flute tone with “openness” and “roundness” (22). These terms are specifically associated with a flautist’s ability to increase the resonance of the sound by creating space in their mouth (i.e., via a relaxed jaw with space between the back molars) and opening their throat (a similar sensation to yawning). Using these physical positions when performing music with typical fingering patterns increases the perceived warmth and resonance of the sound across all registers. Any sound created by alternate fingerings that prevents this resonance or “openness” will be perceived as closed-off or muted and therefore cold. Notes on the flute that are played with standard fingerings thus fall onto the “warm” side of Breault’s axis, and those created by extended techniques fall on the “cold” end.
Contrast between these hot and cold timbres can be heard in Audio Example 3 (1:07– 1:17 in Assimokopolous’s recording), where standard and extended playing techniques are interspersed among one another. The music progresses from a pitch glissando with timbral trilling to conventional technique (staccato eighth notes), followed by flutter tonguing and timbral trilling combined. This passage traverses Breault’s hot/cold axis, following the path of cold hot cold. Considering that 93% of the measures in this piece feature timbres produced by extended techniques that therefore sound “cold,” we could describe Icicle as mostly cold music. This progression is summarized in Figure 3.
Figure 3: Icicle mm. 31–37 with annotations, visualizing Audio Example 3.
Breault’s context as a professional flute player and pedagogue is central to her distinction of hot and cold sounds in Icicle. But adjectives like warm, cold, and hollow are commonly used by musicians and non-musicians alike to describe timbre . Describing instrumental timbre using these terms is frequently reported by studies of timbre semantics (i.e., the study of the language that people use to describe timbres). For instance, when Reymore and Huron (2020) asked participants to describe instrumental timbres, they found that “warm,” “cold,” and “hollow” were all within the list of top 50 sound-describing adjectives. Furthermore, researchers have found that hollow sounds tend to have unique acoustic characteristics. For example, Reymore and Huron (2020) report that the clarinet is often described as hollow. Caetano, Saitis, and Siedenburg (2019) state that this apparent hollowness can be linked to the acoustic structure of the clarinet sound. Instead of sonic energy being distributed relatively equally across all partials above a clarinet’s fundamental pitch, the clarinet sound is characterized by concentrated sonic energy in only the odd-numbered partials above the fundamental pitch. The hollowness of the clarinet sound is therefore mirrored by its hollow acoustic structure. Although Icicle does not feature clarinet, it does feature many hollow sounds, which belong in Breault’s “cold” category of sounds created by extended techniques. Breault’s explicit connection of cold sounds with timbral hollowness and the pervasiveness of these sounds throughout this piece encourage investigation into the acoustic structures that give rise to their hollow quality. In other words, is there a similar correspondence between the acoustic structure and description of hollow/cold sounds in Icicle as exists with the clarinet?
As my analysis shows below, the acoustic structure of the icicle motive reflects both Breault’s and my descriptions of its timbre. This connection holds true with “warm” and “full” timbres produced by standard techniques used elsewhere in the piece. My analysis therefore suggests the possibility of association between a sound’s acoustic structure and whether it is described as “hot” or “cold.”[1] Importantly, although Breault applies the terms “cold” and “hollow” to all the sounds produced by extended techniques throughout Icicle, my analysis focuses on the acoustic structure of the coloured trill only, as it is one of the most pervasive extended techniques in the piece and is an essential, identifying component of the work’s central motive.
As Figure 2 (above) shows, the icicle motive exists in two versions: the first closes with C# and the second ends with D. Audio Example 4 and Audio Example 5 respectively present my recorded performances of each in isolation. In these recordings, I play each motive very slowly to highlight how each combination of closed flute keys (without the thumb) modifies the timbre. The spectral representations of these recordings are given in Figure 4 and Figure 5.
Figure 4: Annotated spectrogram of Audio Example 2 (Icicle motive 1)
Figure 5: Annotated spectrogram of Audio Example 3 (Icicle motive 2)
Notice that in both graphs, there is a gap in the spectral energy of the overtones in the range of approximately 12 000–13 360 Hz. The acoustic visualization of this motive has an element of literal “hollowness,” reflecting both Breault’s and my descriptions of these motives’ character. Breault also describes this timbre as evoking the “transparency of ice” (2013: 17). This gap in the overtone space allows us to “see through” the audio signal, reflecting the essence of transparency.
This gap becomes especially important when comparing it to the spectrogram of the icicle motive played with the thumb key closed. Audio Example 6 and Audio Example 7 present my recordings of how icicle motives 1 and 2, respectively, sound when played with this more standard, thumb-on technique. Figure 6 (Audio Example 6 ) shows a spectrogram of this realization of version 1. Notice that the 1.3kHz gap in the thumb-off realization of this motive is now filled. The gap is also reduced in size due to more spectral energy filling the upper partials in the second version of the Icicle motive, as shown in Figure 7 (Audio Example 7). Whereas the gap in Figure 6 is entirely filled with audio signal in the upper partials, that shown Figure 7 is only reduced in size. Nevertheless, the gap in Figure 7 is much smaller than that in Figure 5 and does not span the entire audio excerpt. The partial and complete reductions in the size of the gaps in the upper partials when the motives are played with the thumb on (Figures and Audio Examples 6 and 7) suggests that the association of standard flute tone with warmth is perhaps justified by more activity in the overtone space. Similarly, the gap in spectral energy in the upper partials shown in Figures 4 and 5 suggests that the association of timbral “coldness” and “hollowness”with extended techniques is justified by the hollow quality of the Icicle motives’ overtone structures.
Figure 6: Annotated spectrogram of icicle motive 1 played with normal flute technique (closed thumb key, Audio Example 6). Compare with Figure 4.
Figure 7: Annotated spectrogram of icicle motive 2 played with standard flute technique (closed thumb key, Audio example 7). Compare with Figure 5.
Figures 4 and 5 also reveal the noisiness component of the coloured trill, and evoke associations of cold with stagnation. Above the 16.2 kHz level in both spectrograms, vertical blue lines of acoustic energy radiate upwards. These likely correspond to the icicle motive’s high concentration of high frequencies, and the aperiodic structure of these vertical lines indicates an element of noisiness present within the sound. These components visualize the breathy timbre of the coloured trill that, to my ear, is evocative of cold, winter winds. Moreover, comparing Figures 4 and 6 reveals that the coloured trill technique (Figure 4) produces a more consistent overtone structure throughout the icicle motive with only very slight changes in fundamental frequency. This is because the open thumb key causes the pitch material in A to progress microtonally from C5 to C#5. As Figure 6 shows, the pitch range of the icicle motive is conversely much larger when the thumb key is closed: the fundamental frequencies traverse almost an entire octave. The gesture’s angular contour and relatively larger pitch range both change the overtone structure of the motive as it progresses through its pitches. The winter season and its accompanying cold and ice are often associated with hibernation and stagnation: ice freezes objects in time. This association is reflected in the relatively consistent overtone structure of the icicle motive’s coloured trill timbre (Figure 4) and contrasted by the changing overtone structure in the “warm” technique (Figure 6).
In conclusion, Icicle is composed of timbres that evoke the winter season; they are characterized as cold, icy, hollow, and transparent by the composer, Breault, and myself. This analysis shows that preliminary parallels can be drawn between such descriptions and the acoustic structure of the icicle motive’s timbre, as the “cold” sounds feature a gap in the upper spectral energy that is filled in the warm sound. The cold sounds also feature more noise in the sound, and a more consistent overtone structure over time than the warm sounds. My analysis therefore supports Breault’s hot/cold axis for analyzing the timbres in this piece, augmenting it by including details about the sounds’ acoustic structures. As Breault suggests, the association of cold with timbres produced by extended techniques such as the coloured trill is heavily context dependent: cold timbres sound as such partially because they occur in relief of the warm ones. Her hot/cold axis could be used in further research to discuss the overall design of the piece, investigating issues such as the frequency of the juxtaposition of warm and cold sounds throughout. I suspect that interspersing cold and warm timbres would offer a new avenue of creating musical tension that is perhaps unique to Icicle. Finally, this analysis provides a premise for future music perception research that hypothesizes a connection between temperature-based semantic descriptors of timbres and their acoustic structures.
Nina Assimakopoulos performing Icicle
[1] This hypothesis requires thorough experimental testing to determine whether the semantic description and its corresponding acoustic structure are truly correlated.
Audio Examples
Works Cited
Aitken, R. (1977). Icicle for Solo Flute. Éditions Transatlantiques.
––––––––. (1977). Icicle for Solo Flute [Recorded by N. Assimakopolous]. YouTube. (2021, December 23). https://www.youtube.com/watch?v=k-EJQGxvb24
––––––––. (2020). “Icicle for Solo Flute.” Robert Aitken: Articles. http://www.bobaitken.ca/styled-3/page23/index.html
Breault, M.H. (2013). L’évocation de la glace et du froid par le timbre de la flute dans Icicle de Robert Aitken. Les Cahiers de la Société québecoise de recherche en musique, 14(1), 17–24. https://doi.org/10.7202/1016194ar
Cook, A. (2013). Aitken: Icicle Program Notes. Between the Ledger Lines: A Blog for the Modern Flutist. https://betweentheledgerlines.wordpress.com/2016/09/27/aitken-icicle-program-notes/
Caetano, M., Saitis, C., & Siedenburg, K. (2019). Audio Content Descriptors of Timbre. In K. Seidenburg, S. McAdams, R. Fay, C. Saitis, and A. Popper (Eds), Timbre: Acoustics, Perception, and Cognition (pp. 297–334). Springer ASA Press. https://doi.org/10.1007/978-3-030-14832-4
Reymore, L., & Huron, D. (2020). Using auditory imagery tasks to map the cognitive linguistic dimensions of musical instrument timbre qualia. Psychomusicology: Music, Mind, and Brain, 30, 124–144. https://doi.org/10.1037/pmu0000263
Reymore, L. (2020). Empirical approaches to timbre semantics as a foundation for musical analysis. Doctoral dissertation, Ohio State University.