| 1. |
- Granqvist, Svante, 1963-, et al.
(författare)
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Simultaneous analysis of vocal fold vibration and transglottal airflow : exploring a new experimental setup
- 2003
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Ingår i: Journal of Voice. - 0892-1997 .- 1873-4588. ; 17, s. 319-330
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Tidskriftsartikel (refereegranskat)abstract
- Summary: The purpose of this study was to develop an analysis system for studying the relationship between vocal fold vibration and the associated transglottal airflow. Recordings of airflow, electroglottography (EGG), oral air pressure, and acoustic signals were performed simultaneously with high-speed imaging at a rate of approximately 1900 frames/s. Inverse filtered airflow is compared with the simultaneous glottal area extracted from the high-speed image sequence. The accuracy of the synchronization between the camera images and the foot pedal synchronization pulse was examined, showing that potential synchronization errors increase with time distance to the synchronization pulse. Therefore, analysis was limited to material near the synchronization pulse. Results corroborate previous predictions that air flow lags behind area, but also they reveal that relationships between these two entities may be complex and apparently varying with phonation mode.
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| 2. |
- Lindestad, Per Å, et al.
(författare)
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Voice source characteristics in mongolian throat singing studied with high-speed imaging technique, acoustic spectra, and inverse filtering
- 2001
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Ingår i: Journal of Voice. - 0892-1997 .- 1873-4588. ; 15:1, s. 78-85
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Tidskriftsartikel (refereegranskat)abstract
- Mongolian “throat singing” can be performed in different modes. In Mongolia, the bass-type is called Kargyraa. The voice source in bass-type throat singing was studied in one male singer. The subject alternated between modal voice and the throat singing mode. Vocal fold vibrations were observed with high-speed photography, using a computerized recording system. The spectral characteristics of the sound signal were analyzed. Kymographic image data were compared to the sound signal and flow inverse filtering data from the same singer were obtained on a separate occasion. It was found that the vocal folds vibrated at the same frequency throughout both modes of singing. During throat singing the ventricular folds vibrated with complete but short closures at half the frequency of the true vocal folds, covering every second vocal fold closure. Kymographic data confirmed the findings. The spectrum contained added subharmonics compared to modal voice. In the inverse filtered signal the amplitude of every second airflow pulse was considerably lowered. The ventricular folds appeared to modulate the sound by reducing the glottal flow of every other vocal fold vibratory cycle.
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| 3. |
- Södersten, M., et al.
(författare)
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Vocal behavior and vocal loading factors for preschool teachers at work studied with binaural DAT recordings
- 2002
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Ingår i: Journal of Voice. - : Mosby. - 0892-1997 .- 1873-4588. ; 16:3, s. 356-371
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Tidskriftsartikel (refereegranskat)abstract
- Preschool teachers are at risk for developing voice problems such as vocal fatigue and vocal nodules. The purpose of this report was to study preschool teachers' voice use during work. Ten healthy female preschool teachers working at daycare centers (DCC) served as subjects. A binaural recording technique was used. Two microphones were placed on both sides of the subject's head, at equal distance from the mouth, and a portable DAT recorder was attached to the subject's waist. Recordings were made of a standard reading passage before work (baseline) and of spontaneous speech during work. The recording technique allowed separate analyses of the level of the background noise, and of the subjects' voice sound pressure level, mean fundamental frequency, and total phonation time. Among the results, mean background noise level for the ten DCCs was 76.1 dBA (range 73.0-78.2), which is more than 20 dB higher than what is recommended where speech communication is important (50-55 dBA). The subjects spoke on an average of 9.1 dB louder (p < 0.0001), and with higher mean fundamental frequency (247 Hz) during work as compared to the baseline (202 Hz) (p < 0.0001). Mean phonation time for the group was 17%, which was considered high. It was concluded that preschool teachers do have a highly vocally demanding profession. Important steps to reduce the vocal loading for this occupation would be to decrease the background noise levels and include pauses so that preschool teachers can rest their voices.
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| 4. |
- Ternström, Sten, et al.
(författare)
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Cancellation of simulated environmental noise as a tool for measuring vocal performance during noise exposure
- 2002
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Ingår i: Journal of Voice. - 0892-1997 .- 1873-4588. ; 16:2, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- It can be difficult for the voice clinician to observe or measure how a patient uses his voice in a noisy environment. We consider here a novel method for obtaining this information in the laboratory. Worksite noise and filtered white noise were reproduced over high-fidelity loudspeakers. In this noise, I I subjects read an instructional text of 1.5 to 2 minutes duration, as if addressing a group of people. Using channel estimation techniques, the site noise was suppressed from the recording, and the voice signal alone was recovered. The attainable noise rejection is limited only by the precision of the experimental setup, which includes the need for the subject to remain still so as not to perturb the estimated acoustic channel. This feasibility study, with 7 female and 4 male subjects, showed that small displacements of the speaker's body, even breathing, impose a practical limit on the attainable noise rejection. The noise rejection was typically 30 dB and maximally 40 dB down over the entire voice spectrum. Recordings thus processed were clean enough to permit voice analysis with the long-time average spectrum and the computerized phonetogram. The effects of site noise on voice sound pressure level, fundamental frequency, long-term average spectrum centroid, phonetogram area, and phonation time were much as expected, but with some interesting differences between females and males.
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| 5. |
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| 6. |
- Ihre, E, et al.
(författare)
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Voice problems as side effects of inhaled corticosteroids in asthma patients - A prevalence study
- 2004
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 18:3, s. 403-414
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Tidskriftsartikel (refereegranskat)abstract
- Voice disturbances in asthma patients may be caused by inhaled corticosteroids. In order to study the prevalence of such voice disturbances, a questionnaire was delivered to asthma patients at three asthma and allergy departments in Stockholm. The questionnaire consisted of 25 questions concerning the asthma disease symptoms, medication, voice function, and voice disturbances. A total of 350 questionnaires were delivered. Response frequency was 80%. There was a significant positive correlation between inhalation of cortison and voice disturbances. Most of the patients complained about hoarseness, followed by throat clearing, a lump in the throat, loss of voice, and less frequently, throat pain. There were no significantly differences between men and women. Elderly had more voice problems than young persons. Patients with voice-demanding professions had more problems than patients who used their voice to a lesser extent during the working day. There was a significant positive correlation between high cortison doses and voice problems as well as between voice problems and acid regurgitation.
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| 7. |
- Mürbe, D., et al.
(författare)
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Effects of a professional solo singer education on auditory and kinesthetic feedback - A longitudinal study of singers' pitch control
- 2004
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 18:2, s. 236-241
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Tidskriftsartikel (refereegranskat)abstract
- The significance of auditory and kinesthetic feedback to pitch control in singing was described in a previous report of this project for students at the beginning of their professional solo singer education.(1) As it seems reasonable to assume that pitch control can be improved by training, the same students were reinvestigated after 3 years of professional singing education. As in the previous study, the singers sang an ascending and descending triad pattern with and without masking noise in legato and staccato and in a slow and a fast tempo. Fundamental frequency and interval sizes between adjacent tones were determined and compared with their equivalents in the equally tempered tuning. The average deviations from these values were used as estimates of intonation accuracy. Intonation accuracy was reduced by masking noise, by staccato as opposed to legato singing, and by fast as opposed to slow performance. The contribution of the auditory feedback to pitch control was not significantly improved after education, whereas the kinesthetic feedback circuit was improved in slow legato and slow staccato tasks. The results support the assumption that the kinesthetic feedback contributes substantially to intonation accuracy.
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| 8. |
- Sundberg, Johan, et al.
(författare)
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Estimating perceived phonatory pressedness in singing from flow glottograms
- 2004
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 18:1, s. 56-62
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Tidskriftsartikel (refereegranskat)abstract
- The normalized amplitude quotient (NAQ), defined as the ratio between the peak-to-peak amplitude of the flow pulse and the negative peak amplitude of the differentiated flow glottogram and normalized with respect to period time, has been shown to be related to glottal adduction. Glottal adduction, in turn, affects mode of phonation and hence perceived phonatory pressedness. The relationship between NAQ and perceived phonatory pressedness was analyzed in a material collected from a professional female singer and singing teacher who sang a triad pattern in breathy, flow, neutral, and pressed phonation in three different loudness conditions (soft, middle, loud). In addition, she also sang the same triad pattern in four different styles of singing, classical, pop, jazz, and blues, in the same three loudness conditions. A panel of experts rated the degree of perceived phonatory press along visual analogue scales. Comparing the obtained mean rated pressedness ratings with the mean NAQ values for the various triads showed that about 73% of the variation in perceived pressedness could be accounted for by variations of NAQ.
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