Introduction
Resonance tube has become preferable due to the dual vibration source effect, that is, vocal folds and the bubbling of the water. Variables such as diameter, depth level in the water, tube material, exercise execution time/frequency, and phonatory tasks play a relevant role in the effect of the execution of resonance tubes. An excessive use of these exercises could trigger vocal discomfort, pain, or higher voice perturbations. Although, evidence describes the effect of some of these variables, the number of repetitions (frequency) of a resonance tube exercise program in a day have not been reported yet.

Aims
The principal aim is to describe the effect of straw phonation frequency (number of repetitions in a day) on voice parameters in healthy adults between 18 and 40 years of age.

Methods
42 participants aged between 20 and 40 years produced at least five seconds of a sustained vowel /a/, and S/Z ratio before and after the voice exercises. They were randomly allocated in 3 different groups according to number of sessions.

Results
Acoustic parameters (Jitter; Shimmer; NHR), EGG measures (OQ; CQ) and S/Z ratio did not illustrate statistically significant results. Only VAS illustrates statistically significant outcomes after 2 and 3 sessions of exercises.

Conclusion
Acoustic parameters did not illustrate significant variations across repetitions, however participants perceived similar positive changes in their voices after practicing vocal exercises. Variables such as minimal submersion of the straw; a small sample size per group, a lack of laryngeal examination, and/or the adaptation of the Vocal Function Exercise (VFE) program might explain these outcomes.