Influence on spectral energy distribution of emotional expression

Purpose: The aim of this study was to determine the influence of emotional expression in spectral energy distribution in professional theater actors. Study Design: The study design is a quasi-experimental study. Method: Thirty-seven actors, native Spanish speakers, were included. All subjects had at least 3 years of professional experience as a theater actor and no history of vocal pathology for the last 5 years. Participants were recorded during a read-aloud task of a 230-word passage, expressing six different emotions (happiness, sadness, fear, anger, tenderness, and eroticism) and without emotion (neutral state). Acoustical analysis with long-term average spectrum included three variables: the energy level difference between the F₁ and fundamental frequency (F₀) regions, ratio between 1-5 kHz and 5-8 kHz, and alpha ratio. Results: All the different emotions differ significantly from the neutral state for alpha ratio and 1-5/5-8 kHz ratio. Only significant differences between "joy," "anger," and " eroticism" were found for L1-L0 ratio. Statistically significant differences between genders for the three acoustical variables were also found. Conclusion: The expression of emotion impacts the spectral energy distribution. On the one hand emotional states characterized by a breathy voice quality such as tenderness, sadness, and eroticism present a low harmonic energy above 1 kHz, high glottal noise energy, and more energy on F₀ than overtones. On the other hand, emotional states such as joy, anger, and fear are characterized by high harmonic energy greater than 1 kHz (less steep spectral slope declination), low glottal noise energy, and more energy on the F₁ than F₀ region.