Lip hyper-articulation in loud voice: Effect on resonance-harmonic proximity.

Men and women speakers were recorded while producing sustained vowels at comfortable and loud levels. Following comfortable speech, loud levels were produced in three different conditions: first without specific instruction (UL); then maintaining the same pitch as the comfortable level (PL); and finally, keeping both pitch and lip articulation constant (PAL). The sound pressure level, the fundamental frequency ( fo), the first two vocal tract resonances (R1 and R2), the lip geometry, and the larynx height were measured. For women, a closer proximity of R1 to its nearest harmonic, nfo, was observed in UL. However, no such increased proximity was found in PL, when speakers could, and did, hyper-articulate. Also, no increased proximity was observed in PAL, when lip articulation was constrained. No significant increase in R1: nfo proximity was observed in men in any of the three loud conditions. Finally, R2 was not observed significantly closer to a voice harmonic in loud speech, for neither men nor women.