Organizations: Department of Earth and Planetary Sciences, University of California, Riverside, CA 92521, USA · School of Systems Science and Industrial Engineering, State University of New York (SUNY), Binghamton, NY 13902, USA · Ronin Institute for Independent Scholarship 2.0, Sacramento, CA 95816, USA · Center for Agrarian Studies, Bandung Institute of Technology (ITB), Bandung, West Java 40132, Indonesia · Atmospheric Science Research Group, Bandung Institute of Technology (ITB), Bandung, West Java 40132, Indonesia · Applied and Environmental Oceanography Research Group, Bandung Institute of Technology (ITB), Bandung, West Java 40132, Indonesia
Sonification -- the mapping of data to non-speech audio -- offers an underexplored channel for representing complex dynamical systems. We treat El Niño-Southern Oscillation (ENSO), a canonical example of low-dimensional climate chaos, as a test case for culturally-situated sonification evaluated through complex systems diagnostics. Using parameter-mapping sonification of the Niño 3.4 sea surface temperature anomaly index (1870--2024), we encode ENSO variability into two traditional Javanese gamelan pentatonic systems (pelog and slendro) across four composition strategies, then analyze the resulting audio as trajectories in a two-dimensional acoustic phase space. Recurrence-based diagnostics, convex hull geometry, and coupling analysis reveal that the sonification pipeline preserves key dynamical signatures: alternating modes produce the highest trajectory recurrence rates, echoing ENSO's quasi-periodicity; layered polyphonic modes explore the broadest phase space regions; and the two scale families induce qualitatively distinct coupling regimes between spectral brightness and energy -- predominantly anti-phase in pelog but near-independent in slendro. Phase space trajectory analysis provides a rigorous geometric framework for comparing sonification designs within a complex systems context. Perceptual validation remains necessary; we contribute the dynamical systems methodology for evaluating such mappings.
Figures & tables
Figure 1: Niño 3.4 SST anomaly index, January 1870 to December 2024 ( N=1,860 ). Red/blue shading: El Niño/La Niña conditions ( ±0.5 °C thresholds). Red circles: extreme events ( ∣θ∣≥2.0 °C). The time series exhibits the irregular quasi-periodicity, amplitude asymmetry, and multi-decadal modulation characteristic of low-dimensional climate chaos.
Mode
Brightness [Hz]
Intensity
DynRng
Percuss
Flux
Pelog Layered
1,238
0.021
2.26
0.065
664
Pelog Alternating
1,064
0.013
2.94
0.055
489
Pelog Melodic
809
0.018
2.18
0.041
568
Pelog Spectral
1,270
0.012
2.96
0.053
988
Slendro Layered
1,863
0.022
2.08
0.134
985
Slendro Alternating
1,233
0.011
3.48
0.074
757
Table 1: Acoustic feature statistics for eight sonification variants. Brightness: mean spectral centroid (Hz); Intensity: mean RMS energy; DynRng: dynamic range ratio; Percuss: mean zero-crossing rate; Flux: mean spectral flux.
Figure 2: Spectral centroid trajectories for pelog modes: (a) layered, (b) alternating, (c) melodic, (d) spectral. Terminal descents near t≈470 s are fade-out artifacts.
Figure 3: Spectral centroid trajectories for slendro modes. Slendro layered (a) achieves the highest mean brightness (1,863 Hz) of all variants.
Figure 4: RMS energy trajectories for pelog modes. All modes show significant negative trends ( p<0.001 ).
Figure 5: RMS energy trajectories for slendro modes. Slendro layered (a) achieves the highest mean energy (0.022) across all variants.
Variable
Mode
xˉ
σx
γx
β
R2
ρ1
Brightness [Hz]
Pelog Layered
1,238
311
0.251
0.031
0.091
0.993
Pelog Spectral
1,270
157
0.123
0.004
0.005
0.958
Slendro Layered
1,863
208
0.112
0.002
0.001
0.980
Slendro Spectral
1,274
162
0.127
0.004
0.006
0.959
Energy [-]
Pelog Layered
0.021
0.005
0.258
−6.1×10−7
0.118
0.998
Pelog Spectral
0.012
0.003
0.284
−1.1×10−7
0.008
0.996
Table 2: Time series statistics for spectral centroid and RMS energy (representative subset). xˉ : mean; σx : standard deviation; γx : coefficient of variation; β : trend slope per frame; R2 : determination coefficient; ρ1 : lag-1 autocorrelation.
Figure 6: Phase space trajectories for pelog variants. Each point represents Γ(m)=[C~norm(m),E~norm(m)] . Colors: red (layered), orange (alternating), green (melodic), navy (spectral).
Figure 7: Phase space trajectories for slendro variants. Note the clear spatial separation of layered mode (a) from other modes—a stronger inter-mode differentiation than observed in the pelog family.
Mode
A
L
η
Cˉn
Eˉn
ρCE
Rϵ
Pelog Layered
0.529
147
0.004
0.302
0.621
− 0.568
0.119
Pelog Alternating
0.285
99.8
0.003
0.236
0.387
− 0.790
0.240
Pelog Melodic
0.356
111
0.003
0.140
0.537
− 0.513
0.183
Pelog Spectral
0.333
166
0.002
0.314
0.354
− 0.362
0.163
Slendro Layered
0.488
183
0.003
0.537
0.665
+ 0.317
0.123
Slendro Alternating
0.301
140
0.002
0.300
0.338
− 0.118
0.230
Table 3: Phase space trajectory metrics. A : convex hull area; L : path length; η : exploration index ( A/L ); Cˉn,Eˉn : centroid coordinates; ρCE : brightness-energy correlation; Rϵ : revisit rate ( ϵ=0.05 ). All correlations significant at p<0.001 .
The project described in this paper explores the informative sonification of data received in real time from a supercomputer. These data capture the current activities in all the nodes of the computer, therefore, their sonification functions as a form of continuous monitoring of the nodes' behavior and, by extension, of the system as a whole. Because such monitoring is theoretically unending, the resulting sonification must be musically capable of conveying information through sound in a way that remains both intelligible and engaging over long durations. Rather than imposing a predefined musical style onto the data, we sought to identify one which the data themselves could plausibly support. From a small set of candidates, we selected EDM because it is a family of genres whose structural and temporal characteristics align well with continuous, data-driven processes and long-term listening. Through this style-based approach, this research builds on the long tradition of computer data sonification while uniquely combining three elements rarely addressed together: monitoring (rather than debugging) as the primary goal, real-time (rather than post-mortem) data interpretation, and generation of virtually infinite and stylistically coherent (rather than incongruous) music.
Marco Alunno, Paolo Bientinesi
Universidad EAFIT · Carrera 49 #7sur-50 · Medelln, Colombia +3
Sonification operates across scientific, artistic, and design contexts, yet its identity remains conceptually ambiguous: is it music, a scientific method, or a hybrid practice? This paper presents a philosophical framework that treats sonification as a coherent, transcategorical practice. Drawing on Gustavo Bueno's materialist gnoseology, we identify its operative core through systematic data-to-sound relationships that define its technical identity. Complementing this with Gilbert Simondon's philosophy of individuation, we show conceptually how sonification adapts across contexts while preserving its operative structure. By distinguishing between technical identity and pragmatic use, this framework clarifies the relationship between sonification, music, and aesthetics, providing researchers and practitioners with a philosophical framework to navigate the field's diversity while maintaining its epistemic and operational integrity.
Rubén García-Benito
Instituto de Astrofísica de Andalucía (IAA), CSIC · PO Box 3004, 18080 Granada, Spain · Todos los Tonos y Ayres Ensemble
Affective visualization can influence how users perceive, interpret, and engage with data by embedding and conveying emotion through visual design. While sound is widely used in media to evoke emotions, little is known about how sonification can support affective visualization. In this work, we investigate how sonification can communicate emotion in uncertainty visualizations through a co-design study. Participants created two sonifications to accompany a visualization: one conveying the affective component of uncertainty and one conveying neutrality. Our findings show that uncertainty was commonly associated with wavy auditory qualities related to an ominous sentiment. On the other hand, neutrality was associated with clear and relaxing auditory qualities. These results provide insights for the design of visualizations that integrate sonification to communicate the affective component of uncertainty.
Marcel-Simon Dutt, Sita A. Vriend, Elias Elmquist +1