Persona: Filipa M.B., Lã
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Filipa M.B., Lã
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Publicación Voice source variation between vowels in male opera singers(Elsevier, 2016-09-01) Sundberg, Johan; Filipa M.B., Lã; Gill, Brian P.; Filipa M.B., LãObjectives: The theory of non-linear source-filter interaction predicts that the glottal voice source should be affected by the frequency relationship between formants and partials. An attempt to experimentally verify this theory is presented. Study design: Glottal voice source and electrolaryngograph (ELG) signal differences between vowels were analyzed in vowel sequences, sung at four pitches with the same degree of vocal loudness by professional opera singers. Also, the relationships between such differences and the frequency distance between the first formant (F1) and its closest partial were examined. Methods: A digital Laryngograph microprocessor was used to simultaneously record audio and ELG signals. The former was inverse-filtered and voice source parameters and formant frequencies were extracted. The amplitude quotient of the derivative of the ELG signal (AQdELG) and the contact quotient were also compared. Results: A one-way repeated measures ANOVA revealed significant differences between vowels, for contact quotient at four pitches and for MFDR at three pitches. For other voice source parameters, differences were found at one or two pitches only. No consistent correlation was found between MFDR and the distance between F1 and its closest partial. Conclusions: The glottal voice source tends to vary between vowels, presumably because of non-linear source-filter interaction, but the variation does not seem to be dependent upon the frequency distance between F1 and its closest partialPublicación Glottal airflow and glottal area waveform characteristics of flow phonation in untrained vocally healthy adults(Elsevier, 2022-01) Patel, Rita R.; Sundberg, Johan; Gill, Brian P.; Filipa M.B., Lã; Filipa M.B., LãObjective To examine flow phonation characteristics with regard to vocal fold vibration and voice source properties in vocally healthy adults using multimodality voice measurements across various phonation types (breathy, neutral, flow, and pressed) and loudness conditions (typical, loud, and soft). Participants and Methods Vocal fold vibration, airflow, acoustic, and subglottal pressure was analyzed in 13 untrained voices (six female and seven male). Participants repeated the syllable / pæ:/ using breathy, neutral, flow, and pressed phonation during typical, loud, and soft loudness conditions. Glottal area (GA) waveforms were extracted from high-speed videoendoscopy; glottal flow was derived from inverse filtering the airflow or the audio signal; and subglottal pressure was measured as the intraoral pressure during /p/ occlusion. Results Changes in phonation type and loudness conditions resulted in systematic variations across the relative peak closing velocity derived from the GA waveform for both males and females. Amplitude quotient derived from the flow glottogram varied across phonation types for males. Conclusion Multimodality evaluation using the GA waveform and the inverse filtered waveforms revealed a complex pattern that varied as a function of phonation types and loudness conditions across males and females. Emerging findings from this study suggests that future large-scale studies should focus on spatial and temporal features of closing speed and closing duration for differentiating flow phonation from other phonation types in untrained adults with and without voice disorders.Publicación Physiology and its impact on the performance of singing(Oxford University Press, 2019) Filipa M.B., Lã; Gill, Brian P.; Filipa M.B., Lã