Lip Trill: Aerodynamic, Acoustic, and Laryngeal Interactions

Area of Science:

• Vocal pedagogy
• Speech science
• Acoustic phonetics

Background:

• Semioccluded vocal tract (SOVT) exercises like lip trills are widely used by voice professionals.
• Understanding the physiological mechanisms of SOVT exercises is crucial for effective voice training.
• Previous research has explored various aspects of SOVT exercises, but the interplay of aerodynamic and acoustic signals during lip trills requires further investigation.

Purpose of the Study:

• To investigate the relationships between aerodynamic and acoustic signals during lip trills.
• To analyze the effects of lip trills on glottal parameters and airflow.
• To examine the impact of voiced versus unvoiced lip trills on oral air pressure.

Main Methods:

• A trained female singer performed voiced and unvoiced lip trills, and a /bap:/ syllable string.
• Audio, airflow, electroglottography (EGG), and oral air pressure signals were recorded.
• EGG signals were used to calculate EGGW25, EGG height (EGGH), and fundamental frequency (f_o).

Main Results:

• Lip trills significantly reduced EGGW25 (a measure of glottal adduction) compared to vowel production.
• Oral air pressure during voiced lip trills remained below atmospheric pressure and was higher during unvoiced lip trills.
• Within a lip trill cycle, EGGW25 and EGGH decreased with lip opening, while f_o increased, sometimes exceeding the target frequency.

Conclusions:

• Lip trills facilitate reduced glottal adduction, indicated by lower EGGW25.
• The study revealed complex, counterintuitive relationships between transglottal pressures, glottal adduction, and airflow during lip separation.
• Fundamental frequency changes during lip separation were larger than anticipated, and unvoiced lip trills showed higher oral pressures due to the absence of glottal resistance.