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Self-Oscillating Vocal Fold Models Coupled to 3D-Printed Vocal Tracts, Part I: Aerodynamic Threshold Measures with Semi-Occluded Vocal Tract (SOVT) Tubes
Journal article   Peer reviewed

Self-Oscillating Vocal Fold Models Coupled to 3D-Printed Vocal Tracts, Part I: Aerodynamic Threshold Measures with Semi-Occluded Vocal Tract (SOVT) Tubes

Nicholas A. May, Ronald C. Scherer and David P. Meyer
Journal of voice
02/18/2026
DOI: 10.1016/j.jvoice.2026.01.034
PMID: 41714208

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Abstract

Studies of voice production often utilize models to examine aerodynamic phenomena that would be difficult to access in vivo in human subjects. Physical, synthetic, self-oscillating vocal fold models (SO-VFMs) allow for precise control over geometric parameters and material properties and allow for examination of vocal kinematics, acoustics, and aerodynamics. To date, there is little extant research investigating the effects of semi-occluded vocal tract (SOVT) exercise tubes on aerodynamic threshold measures in SO-VFMs coupled to anatomically analogous 3D-printed vocal tracts (VTs). Controlled experimental laboratory study. Magnetic resonance imaging (MRI)-derived 3D-printed models of an adult male producing the vowels /ɑ/ and /u/ were coupled to multilayered SO-VFMs that yield phonatory aspects analogous to human vocal fold vibration. Phonation threshold pressure (PTP), phonation threshold flow (PTF), and fundamental frequency (fo) at onset and offset of phonation were measured. Experimental conditions included: 1) a no VT condition, 2) a uniform cylindrical VT condition, 3) 3D-printed MRI-based /ɑ/ and /u/ vowels, and 4) conditions in which the MRI-based vowels were extended by tubes with different inner diameters and lengths simulating SOVT tubes. SOVT tubes significantly reduced PTPs and PTFs with the lowest values generally observed for longer and wider tubes geometries. PTPs differences between /u/ vowel + tube and /ɑ/ vowel + tube conditions were not statistically significant in most cases, suggesting that vowel effects may depend on model-specific geometry rather than a universal vowel difference. PTPonset-PTPoffset hysteresis was observed with onsets having higher transglottal pressures than offsets, and half-length tubes tended to yield higher fos than full-length tubes; however, across the various tube geometries, fo increased with tube length. Aerodynamic and acoustic interactions may influence vocal function during SOVT exercises.
 3D-printed vocal tract Phonation threshold flow (PTF) Phonation threshold pressure (PTP) Self-oscillating vocal fold model (SO-VFM) Semi-occluded vocal tract (SOVT)

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