Flow ball-assisted training : immediate effects on vocal fold contacting

• Background: The flow ball is a device that creates a static backpressure in the vocal tract while providing real-time visual feedback of airflow. A ball height of 0 to 10 cm corresponds to airflows of 0.2 to 0.4. L/s. These high airflows with low transglottal pressure correspond to low flow resistances, similar to the ones obtained when phonating into straws with 3.7 mm diameter and of 2.8 cm length. Objectives: To investigate whether there are immediate effects of flow ball-assisted training on vocal fold contact. Methods: Ten singers (five males and five females) performed a messa di voce at different pitches over one octave in three different conditions: before, during and after phonating with a flow ball. For all conditions, both audio and electrolaryngographic (ELG) signals were simultaneously recorded using a Laryngograph microprocessor. The vocal fold contact quotient Qci (the area under the normalized EGG cycle) and dEGGmaxN (the normalized maximum rate of change of vocal fold contact area) were obtained for all EGG cycles, using the FonaDyn system. We introduce also a compound metric Ic ,the ‘index of contact’ [Qci × log10(dEGGmaxN)], with the properties that it goes to zero at no contact. It combines information from both Qci and dEGGmaxN and thus it is comparable across subjects. The intra-subject means of all three metrics were computed and visualized by colour-coding over the fo-SPL plane, in cells of 1 semitone × 1 dB. Results: Overall, the use of flow ball-assisted phonation had a small yet significant effect on overall vocal fold contact across the whole messa di voce exercise. Larger effects were evident locally, i.e., in parts of the voice range. Comparing the pre-post flow-ball conditions, there were differences in Qci and/or dEGGmaxN. These differences were generally larger in male than in female voices. Ic typically decreased after flow ball use, for males but not for females. Conclusion: Flow ball-assisted training seems to modify vocal fold contacting gestures, especially in male singers.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Signalbehandling (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Signal Processing (hsv//eng)

Nyckelord

electroglottography

semi-occluded vocal tract

singing voice

Tal- och musikkommunikation

Speech and Music Communication

Publikations- och innehållstyp

ref (ämneskategori)

kon (ämneskategori)