Acoustic markers of emotional expression in professional lyrical singing

This study examines the extent to which induced emotions (joy versus anger) modulate the acoustic architecture of professional lyrical sopranos. Fundamentally aligned with the 4E/5E paradigm of cognitive science, this research aims to analyze the extent to which induced affect reconfigures the vocal system during performance. Grounded in Non-Linear Source-Filter Theory, the study evaluates the functional interaction between glottal source dynamics (F ₀, SPL, and vibrato) and vocal filter strategies (formants F ₁ to F ₅).

Three professional Category 2.1 soprano singers underwent an emotional induction protocol using validated film fragments to establish conditions of affective congruence and incongruence while performing selected musical excerpts. Standardized multi-parametric quantitative acoustic tracking was conducted to isolate individual harmonic profiles and verify upper formant configurations.

The effective induction of joy fosters resonance optimisation through efficient "R ₁:f ₀ tuning" and a marked expansion of the vowel space (F ₁ - F ₂ gap). In Singer 1, joy facilitated a precise alignment of F ₃ and F ₅ during the central vibrato cycle, clustering the Singer's Formant to enhance spectral brightness and "squillo". Conversely, induced anger prioritises physiological constriction of the vocal tract and increased glottal adduction-characterised by pronounced elevations in SPL and heightened subglottic pressure. In Singers 2 and 3, although the distances between upper formants remained broad, they maintained vocal projection through an intensified Singer's Formant Cluster (SFC) achieved via more efficient excitation of higher resonances.

These findings suggest that authentic emotional states physically and involuntarily optimise the singer's acoustic output, whereas conflicting affect degrades fine motor technical stability. The results substantiate that classical performance is an enactive process of embodiment, offering key implications for voice pedagogy through explicit parameter modulation training and real-time acoustic feedback systems.