OBJECTIVE: To evaluate changes in spectrograms, sound pressure level (SPL), and self-reported sensations after phonation in a glass tube immersed in water (PGTIW) in normal women. METHODS: Of 24 women, aged 18 to 40 years, 12 were assigned to the study group (SG) and 12 to the control group (CG); we evaluated their phonation of the vowel /a:/ and assessed the (NPS) and self-reported vocal sensations, before and after PGTIW in the SG and after a period of silence in the CG. Wideband and narrowband spectrographic analysis was performed. Statistical significance was evaluated using the Wilcox on, Chi-square, and Spearman tests (P< 0.05 was considered significant). RESULTS: In the GE, increases in the intensity of the fourth formant, the definition of the first formant and of harmonics, the number of harmonics, the SPL value, and the sensation of a better voice were observed after PGTIW. There was a significant positive correlation between PGTIW and the sensation of a better voice, improved definition of the second and third formants, and smoothness of the tracing. CONCLUSION: PGTIW was associated with increased SPL, resonance, and vocal projection, as well as increased harmonic energy and decreased periodic signals; it improving the subjective sensations of vocal production.
