Table 1.
Age, years (yr) of prior singing lessons, voice category and values of the difference of the Hammarberg Index in speech and singing (ΔHI) for all subjects including mean values.
Fig 1.
From the MRI to the segmented vocal tract.
Typical example of the centerline (*) position used for segmentation (A). Four examples of cross-sections at different levels, as indicated (B). The corresponding 3D representation of the segmented vocal tract (C).
Fig 2.
Visualization of the analyzed vocal tract measures.
(A) 3D model of the complete vocal tract in a right-oblique projection within a midsagital section of the corresponding MRI data. (B) 3D model of the lower vocal tract showing the location of the reference plane at the top of the arytenoids, the selected volume measures: in purple: hypopharyngeal volume (HPV = volume from reference plane 10 mm upwards), in blue: endolaryngeal volume (ELV = volume from reference plane to lower ventricular folds) as well as the position of the area measures: hypopharyngeal area (HPA) and endolaryngeal area (ELA) with the corresponding segmented MR images (HPA/(C) and ELA/(D)).
Fig 3.
Schematic illustration of helplines A and B.
Projection of the helplines A and B on the cervical spine and larynx structures. The helplines served for measuring the LH. ‘I’ and ‘VII’ denote the respective vertebra.
Fig 4.
Lowering of larynx position in singing.
Values averaged across subjects for the lowering of the larynx (LH for larynx height) in singing compared to speech-like phonation for the indicated vowels. Boxes represent means +/-1SD. Bold base line representing no change in larynx position.
Fig 5.
Widening of larynx area and volume in singing.
Percentage change (pc) of endolaryngeal area (ELA)(A) and the endolaryngeal volume (ELV)(B) from speech-like phonation to singing, averaged across subjects for the indicated vowels. Boxes represent means +/-1SD.
Fig 6.
Widening of hypopharynx area and volume in singing.
Percentage change (pc) of hypopharyngeal area (HPA)(A) and hypopharyngeal volume (HPV)(B) from speech-like phonation to singing, averaged across subjects for the indicated vowels. Boxes represent means +/-1SD.
Fig 7.
Correlation of hypopharyngeal area and volume measures.
Hypopharyngeal area (HPA) multiplied by the height of HPV(9.765 mm) plotted against hypopharyngeal volume (HPV). Individual values for both phonation modes and all vowels.
Fig 8.
Drop of area and volume ratio in singing.
Ratios of the endolaryngeal area (ELA) to the hypopharyngeal area (HPA)(A) and the endolaryngeal volume (ELV) to the hypopharyngeal volume (HPV)(B) averaged across subjects for indicated vowels in speech-like phonation and singing. Boxes represent means +/-1SD.
Fig 9.
Correlation of the laryngeal lowering to the hypopharyngeal widening.
Individual values of the laryngeal lowering (ΔLH) plotted against the percentage change (pc) of the hypopharyngeal area (HPA) in singing compared to the speech-like phonation for the indicated vowels.
Fig 10.
Correlation of acoustics to hypopharyngeal widening.
Mean values across all vowels for each subject of percentage change (pc) of the hypopharyngeal area (HPA) and the difference of the Hammarberg Index in speech-like phonation and singing (ΔHI).
Fig 11.
Influence of lower vocal tract (VT) on transfer function.
(A) Area functions of the vowel /a/ of subject 8 in the singing (dark red) and the speech-like configuration (dark blue) and the crosswise exchange of the lower VT (slim curves: hybrid of upper VT during singing and lower VT during speech-like phonation in light red and hybrid of upper VT/speech-like and lower VT/singing in light blue). Magnification showing the exchange spot. (B) Transfer functions computed with PRAAT based on the area functions from (A). Colors correspond to the colors used in panel (A).