Vocal tract adjustments for expressing bright and dark timbres in operatic singing

Abstract

This study examined how professional opera singers modulate vocal tract configurations to express "bright" and "dark" timbres. In the "bright" condition, F2–F3 frequencies increased with lip opening, whereas in the "dark" condition, F1 and F3 frequencies decreased with pharyngeal expansion and laryngeal lowering. These effects were more pronounced at lower pitches. An untrained participant showed minimal articulatory or acoustic variation across conditions. Simulations based on vocal-tract area functions confirmed F1–F2 changes but only weakly reflected F3, suggesting additional lateral or vertical adjustments beyond the midsagittal plane. These findings clarify articulatory–acoustic mechanisms of timbre control in operatic singing.