Background:Voice production results from the complex interaction between airflow, the vocal folds, and the vocal tract—not merely from air passing through vibrating tissues. Vocal output is influenced by multiple factors, including impedance, resonance, and the continuously changing shape of vocal tract cavities during speech or singing. These dynamic and rapid changes mobilize acoustic energy within the vocal tract.
Research and therapeutic approach aim to explore strategies for controlling airflow and pressure to enhance vocal performance to improve vocal function. In acoustic and vocal systems, impedance reflects resistance to sound flow and its reactive behavior through inertance. However, as in other forms of energy transfer (electrical, mechanical, etc.), voice production involves not only resistance but also regions that facilitate airflow—referred to as admittance.
Objective: The objective of this experiment was to determine whether the Dynamics of Vocal Acoustic Energy Flow (DAEF) can influence vocal outcomes. We hypothesized that phonation benefits from vocal exercises performed during tissue tension changes induced by controlled positive (CPAP) or negative (NPAP) airway pressures using a custom-designed device.
Methods: Twenty participants without vocal pathology were included. Ten subjects performed a 10-minute session using the device with alternating positive and negative pressures while producing isolated words and phrases. The remaining ten participants used the device under constant pressure (sham condition). Both subjects and experimenters were blinded to condition. Pre- and post-session assessments included subjective self-ratings and acoustic analysis.
Results: Participants who performed vocal exercises with CPAP and NPAP demonstrated significant improvements in perceived vocal comfort and objective acoustic parameters compared with the sham group.
Conclusions: Working with the Dynamics of Vocal Acoustic Energy Flow (DAEF) promotes measurable vocal changes and an immediate sensation of ease during phonation. The method is simple to apply and offers promising potential as a therapeutic tool for optimizing vocal function.