Controlled voice quality modifications

Within-speaker variability, which results from the plasticity of speech production, is an inherent feature of speaker comparison. This study examines targeted modifications of voice quality, both phonatory and articulatory, in Czech. Fifteen speakers were instructed to read a text in 15 different versions (e.g. palatalised voice, denasalised voice, breathy phonation, or a combination of open jaw and creaky voice). Acoustic analyses revealed that F3 is relatively stable across various voice quality settings, while harmonicity and spectral slope indicators are sensitive to the phonatory modifications. A perceptual test, administered online to 120 participants, showed that palatalised, pharyngealised, creaky, and pressed voice were regarded as most different from the speakers’ habitual voices. Finally, automatic speaker recognition scores were very good with the targeted voice quality modifications, with LLR between 3 and 10. Pressed phonation turned out to have the greatest effect on all three types of analysis.