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Filipa M.B., Lã

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Filipa M.B., Lã
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  • 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
  • Publicación
    Avaliação aerodinâmica e acústica da fonte de voz
    (Thieme Revinter, 2022) Sundberg, Johan; Filipa M.B., Lã; Filipa M.B., Lã
  • Publicación
    Real-Time visual feedback in singing pedagogy: current trends and future directions
    (MDPI, 2022-10-25) Filipa M.B., Lã; Barro Fiuza, Mauro; Filipa M.B., Lã
    Singing pedagogy has increasingly adopted guide awareness through the use of meaningful real-time visual feedback. Technology typically used to study the voice can also be applied in a singing lesson, aiming at facilitating students’ awareness of the three subsystems involved in voice production—breathing, oscillatory and resonatory—and their underlying physiological, aerodynamical and acoustical mechanisms. Given the variety of real-time visual feedback tools, this article provides a comprehensive overview of such tools and their current and future pedagogical applications in the voice studio. The rationale for using real-time visual feedback is discussed, including both the theoretical and practical applications of visualizing physiological, aerodynamical and acoustical aspects of voice production. The monitorization of breathing patterns is presented, displaying lung volume as the sum of abdominal and ribcage movements signals. In addition, estimates of subglottal pressure are visually displayed using a subglottal pressure meter to assist with the shaping of musical phrases in singing. As to what concerns vibratory patterns of the vocal folds and phonatory airflow, the use of electroglottography and inverse filters is applied to monitor the phonation types, voice breaks, pitch and intensity range of singers of different music genres. These vocal features, together with intentional voice distortions and intonation adjustments, are also displayed using spectrographs. As the voice is invisible to the eye, the use of real-time visual feedback is proposed as a key pedagogical approach in current and future singing lessons. The use of such an approach corroborates the current trend of developing evidence-based practices in voice education.
  • Publicación
    Kulning: Acoustic and Perceptual Characteristics of a Calling Style Used Within the Scandinavian Herding Tradition
    (Elsevier, 2022-01-03) Rosenberg, Susanne; Sundberg, Johan; Filipa M.B., Lã; Filipa M.B., Lã
    Kulning, a loud, high-pitched vocal calling technique pertaining to the Scandinavian herding system, has attracted several researchers' attention, mainly focusing on cultural, phonatory and musical aspects. Less attention has been paid to the spectral and physiological properties that characterize Kulning tones, and also if there is a physiologically optimum pitch range. We analyzed tones produced by ten participants with varying experience in Kulning. They performed a phrase, pitch range G5 to C6 (784 to 1046 Hz), in three different conditions: starting (1) on pitch A5, (2) on the participant's preferred pitch, and (3) after the deepest possible inhalation, also on the participant's preferred pitch subglottal pressure (Psub) was measured as the oral pressure during /p/-occlusion. The quality of the Kulning was rated by a group of experts. The highest-rated tones all had a sound pressure level (SPL) at 0.3 m exceeding 115 dB and a pitch higher than 1010 Hz, while the SPL of the lowest rated tones was less than 108 dB at a pitch below 900 Hz. A multiple regression analysis was performed to evaluate the relationship between the ratings and Psub), SPL, level of the fundamental and the frequency at which a spectrum envelope dip occurred. Highly rated tones were started at maximum lung volumes, and on participants’ preferred pitches. They all shared a high frequency of the spectrum envelope dip and a high level of the fundamental. In decreasing order of ratings, Condition 3 showed the highest values followed by Condition 2 and Condition 1. Each singer seemed to perform best within an individual Psub and pitch range. The relevance of the results to voice pedagogy, artistic, and compositional work is discussed.
  • Publicación
    Singing at menopause: a systematic review with pedagogical implications
    (SAGE, 2021-12-16) Sevillano García, María Luisa; Filipa M.B., Lã; Barro Fiuza, Mauro; Filipa M.B., Lã
    Menopause is a certainty in a female singer’s life; depletion of estrogens may lead to physical, mental, and vocal symptoms. To investigate the extent to which these symptoms affect singers, a systematic literature review was carried out using eight interdisciplinary bibliographic databases. Combinations of the following key words were used: menopause, climacterium, singing, singers, and choir. From 18 studies, including three doctoral dissertations and a master’s thesis, only 10 met the inclusion criteria. The heterogeneity of study designs and methods of data collection and analysis precluded the carrying out of a meta-analysis. Instead, descriptors of symptoms affecting the voice, and vocal characteristics associated with menopause (menopause descriptors) were categorized, and their frequency of occurrence determined, according to six types of primary dataset: (1) self-reported symptoms, (2) acoustic characteristics, (3) observations of the larynx, (4) perceptual evaluations, (5) analysis of electrolaryngographic waveform characteristics, and (6) analysis of hormone concentrations. The descriptors that occurred most frequently in the literature concerned aspects of voice production, whereas those concerning vocal health, and vocal practice and performance, were less common. Of the three subsystems that comprise the vocal instrument, the vibrating vocal folds seem to be more affected than breathing and resonance. Changes in vocal range, timbre, endurance, and vocal fold mobility occur during menopause, affecting singers’ voice quality. Some singers reported that their ability to perform was compromised, mainly due to memory lapses and lack of confidence. Maintaining regular singing and practicing semi-occluded vocal tract exercises throughout the menopausal transition seem to help singers to overcome the negative impacts of menopause on vocal performance.
  • Publicación
    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., Lã
    Objective 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
    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., Lã
    Objectives: 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 partial
  • Publicación
    Augmented visual-feedback of airflow: Immediate effects on voice-source characteristics of students of singing
    (['SAGE', 'SEMPRE'], 2021-07-12) Filipa M.B., Lã; Sundberg, Johan; Granqvist, Svante; Filipa M.B., Lã
    Glottal adduction is a crucial aspect in voice education and vocal performance: it has major effects on phonatory airflow and, consequently, on voice timbre. As the voice is a non-visible musical instrument, controlling it could be facilitated by providing real-time visual feedback of phonatory airflow. Here, we test the usefulness of a flow ball (FB) training device, visualizing, in terms of the height of a polystyrene ball placed in a plastic basket, phonatory airflow during phonation. Audio and electroglottographic recordings of five postgraduate, classically trained singer students were made under three subsequent conditions: before, during, and after phonating into the FB. The calibrated audio signal was inverse-filtered, using an electroglottograph signal to guide the manual tuning of the inverse filters. Mean phonatory airflow, peak-to-peak pulse amplitude, and normalized amplitude quotient were extracted from the resulting flow glottograms. After the FB condition, increases of mean flow and peak-to-peak pulse amplitude were observed in four singers. In addition, the singers’ mean normalized amplitude quotient increased significantly. The findings, although exploratory, suggest that reduction of glottal adduction.
  • Publicación
    Self-Perceived Voice Handicap During COVID19 Compulsory Facemask Use: A Comparative Study Between Portuguese and Spanish Speakers
    (Elsevier, 2024-08-02) Polo Cano, Nuria; Filipa M.B., Lã
    This study investigates self-perceptions of voice-related handicap as a function of facemask use in the general working population during the COVID19 outbreak, using the Voice Handicap Index (VHI). Each VHI item was answered twice in a row; the first answer referred to the condition of not wearing a facemask (henceforth, the Without condition) and the second to the condition of using a facemask (henceforth, the With condition). VHI scores were collected via Google Forms (Google, Mountain View, California), targeting 2 groups of speakers of different nationalities, Portuguese (n = 261) and Spanish (n = 297). A Wilcoxon test was carried out to compare VHI scores between With and Without conditions for each group of speakers; a Mann-Whitney U test was used to compare groups within each condition. Results suggested that VHI overall scores and scores for all dimensions were higher for the With condition, for both Portuguese and Spanish speakers. When comparing groups of speakers, Spanish speakers presented higher scores for functional and emotional dimensions, for both With and Without conditions. In addition, the overall score for the Without condition was higher for Spanish speakers. No differences between groups were found for the total VHI score for the With condition. When comparing overall VHIdiff between speakers, that is, the difference in the VHI total score between With and Without conditions, no significant differences could be found. Thus, a multiple regression analysis was carried out between the VHIdiff and the independent variables of interest: age, sex, smoking habits, professional occupation, nationality, facemask type and its hours of use. The resulting model providing the highest association suggested that 2.5% of the variation in overall VHIdiff total score could be associated with sex, smoking habits, and professional level. Female smokers who use their voices during prolonged hours at work (e.g., teachers, lawyers, sales people) presented a higher VHI total score when wearing a mask. Future voice-related health interventions should address preventive strategies towards speaking behaviors leading to vocal fatigue and vocal effort as a consequence of compulsory facemask use, especially with respect to female professional voice users who smoke
  • Publicación
    Flow ball-assisted voice training: immediate effects on vocal fold contacting
    (Elsevier, 2020-09-01) Filipa M.B., Lã; Ternström, Sten; Filipa M.B., Lã
    Objective Effects of exercises using a tool that promotes a semi-occluded artificially elongated vocal tract with real-time visual feedback of airflow – the flow ball – were tested using voice maps of EGG time-domain metrics. Methods Ten classically trained singers (5 males and 5 females) were asked to sing messa di voce exercises on eight scale tones, performed in three consecutive conditions: baseline (‘before’), flow ball phonation (‘during’), and again without the flow ball (‘after’). These conditions were repeated eight times in a row: one scale tone at a time, on an ascending whole tone scale. Audio and electroglottographic signals were recorded using a Laryngograph microprocessor. Vocal fold contacting was assessed using three time-domain metrics of the EGG waveform, using FonaDyn. The quotient of contact by integration, Qci, the normalized peak derivative, QΔ, and the index of contacting Ic, were quantified and compared between ‘before’ and ‘after’ conditions. Results Effects of flow ball exercises depended on singers’ habitual phonatory behaviours and on the position in the voice range. As computed over the entire range of the task, Qci was reduced by about 2% in five of ten singers. QΔ was 2–6% lower in six of the singers, and 3–4% higher only in the two bass-baritones. Ic decreased by almost 4% in all singers. Conclusion Overall, vocal adduction was reduced and a gentler vocal fold collision was observed for the ‘after’ conditions. Significance Flow ball exercises may contribute to the modification of phonatory behaviours of vocal pressedness.