| 1. |
- Alku, Paavo, et al.
(författare)
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An amplitude quotient based method to analyze changes in the shape of the glottal pulse in the regulation of vocal intensity
- 2006
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 120:2, s. 1052-1062
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Tidskriftsartikel (refereegranskat)abstract
- This study presents an approach to visualizing intensity regulation in speech. The method expresses a voice sample in a two-dimensional space using amplitude-domain values extracted from the glottal flow estimated by inverse filtering. The two-dimensional presentation is obtained by expressing a time-domainmeasure of the glottal pulse, the amplitude quotient (AQ), as a function of the negative peak amplitude of the flow derivative (d(peak)). The regulation of vocal intensity was analyzed with the proposed method from voices varying from extremely soft to very loud with a SPL range of approximately 55 dB. When vocal intensity was increased, the speech samples first showed a rapidly decreasing trend as expressed on the proposed AQ-d(peak) graph. When intensity was further raised, the location of the samples converged toward a horizontal line, the asymptote of a hypothetical hyperbola. This behavior of the AQ-d(peak) graph indicates that the intensity regulation strategy changes from laryngeal to respiratory mechanisms and the method chosen makes it possible to quantify how control mechanisms underlying the regulation of vocal intensity change gradually between the two means. The proposed presentation constitutes an easy-to-implement method to visualize the function of voice production in intensity regulation because the only information needed is the glottal flow wave form estimated by inverse filtering the acoustic speech pressure signal.
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| 2. |
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| 3. |
- Björkner, Eva
(författare)
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Musical theater and opera singing - Why so different? : A study of subglottal pressure, voice source, and formant frequency characteristics
- 2008
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 22:5, s. 533-540
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Tidskriftsartikel (refereegranskat)abstract
- The considerable voice timbre differences between musical theater (MT) and western operatic singers are analyzed with respect to voice source and formant frequencies in five representatives of each singer group. Audio, subglottal pressure (P(sub)), and electroglottograph (EGG) signals were recorded while the subjects sang a sequence of [pae:] syllables starting at maximal vocal loudness and then gradually decreasing vocal loudness. The task was performed at each of two fundamental frequencies (F(0)), approximately one octave apart. Ten equally spaced P(sub) values were then selected for each F(0). The subsequent vowels were analyzed in terms of flow glottograms derived by inverse filtering the audio signal, which also yielded formant frequency data. Period time (T(0)), peak-to-peak pulse amplitude (U(p-t-p)), and maximum flow declination rate (MFDR) were measured from the flow glottograms while closed quotient Q(closed) (T(cl)/T(0)) was determined in combination with the differentiated EGG signal. Also the relationship between the first and the second harmonic in the spectrum (H(1)-H(2)), the amplitude quotient (AQ), that is, the ratio between U(p-t-p) and MFDR, and normalized AQ, that is, AQ normalized with respect to period time was calculated as well as the sound pressure level. The results showed that both the MT and the opera singers varied their P(sub) systematically, approximately doubling P(sub) for a doubling of F(0). For a given value of P(sub), the MT singers produced higher values of MFDR, U(p-t-p), and Q(closed), and lower values of H(1)-H(2), indicating a weaker fundamental. Further, the MT singers showed higher formant frequencies and did not show the opera singers' characteristic clustering of F(3), F(4), and F(5).
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| 4. |
- Björkner, Eva, et al.
(författare)
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Subglottal pressure and NAQ variation in voice production of classically trained baritone singers
- 2005
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Ingår i: 9th European Conference on Speech Communication and Technology. - Lisbon, Portugal. ; , s. 1057-1060
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Konferensbidrag (refereegranskat)abstract
- The subglottal pressure (Ps) and voice source characteristics of five professional baritone singers were analyzed. Glottal adduction was estimated with amplitude quotient (AQ), defined as the ratio between peak-to-peak pulse amplitude and the negative peak of the differentiated flow glottogram, and with normalized amplitude quotient (NAQ), defined as AQ divided by fundamental period length. Previous studies show that NAQ and its variation with Ps represent an effective parameter in the analysis of voice source characteristics. Therefore, the present study aims at increasing our knowledge of these two parameters further by finding out how they vary with pitch and Ps in operatic baritone singers, singing at high and low pitch. Ten equally spaced Ps values were selected from three takes of the syllable [pae], repeated with a continuously decreasing vocal loudness and initiated at maximum vocal loudness. The vowel sounds following the selected Ps peaks were inverse filtered. Data on peak-to-peak pulse amplitude, maximum flow declination rate, AQ and NAQ will be presented.
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| 5. |
- Björkner, Eva, et al.
(författare)
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Subglottal Pressure and Normalized Amplitude Quotient Variation in Classically Trained Baritone Singers
- 2006
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Ingår i: Logopedics, Phoniatrics, Vocology. - : Informa UK Limited. - 1401-5439 .- 1651-2022. ; 31:4, s. 157-165
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Tidskriftsartikel (refereegranskat)abstract
- The subglottal pressure (Ps) and voice source characteristics of five professional baritone singers have been analyzed and the normalized amplitude quotient (NAQ), defined as the ratio between peak-to-peak pulse amplitude and the negative peak of the differentiated flow glottogram and normalized with respect to the period time, was used as an estimate of glottal adduction. The relationship between Ps and NAQ has been investigated in female subjects in two earlier studies. One of these revealed NAQ differences between both singing styles and phonation modes, and the other, based on register differences in female musical theatre singers, showed that NAQ differed between registers for the same PPs value. These studies thus suggest that NAQ and its variation with PPs represent a useful parameter in the analysis of voice source characteristics. The present study aims at increasing our knowledge of the NAQ parameter further by finding out how it varies with pitch and PPs in professional classically trained baritone singers, singing at high and low pitch (278 Hz and 139 Hz, respectively). Ten equally spaced Ps values were selected from three takes of the syllable [pae:], initiated at maximum vocal loudness and repeated with a continuously decreasing vocal loudness. The vowel sounds following the selected PPs peaks were inverse filtered. Data on peak-to-peak pulse amplitude, maximum flow declination rate and NAQ are presented.
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| 6. |
- Björkner, Eva, et al.
(författare)
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Voice acoustic parameters for detecting signs of early cognitive impairment
- 2017
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Ingår i: PEVOC (PanEuropean Voice Conference) 12, August 30th - September 1st 2017, Ghent, Belgium.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aiding the detection of very early cognitive impairment in Alzheimer's disease (AD) and assessing the disease progression are essential foundations for effective psychological assessment, diagnosis and planning. Efficient tools for routine dementia screening in primary health care, particularly non-invasive and cost-effective methods, are desirable. The aim of this study is to find out if voice acoustic analysis can be a useful tool for detecting signs of early cognitive impairment.
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| 7. |
- Björkner, Eva, et al.
(författare)
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Voice source characteristics in different registers in classically trained female musical theatre singers
- 2004
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Ingår i: Proceedings of ICA 2004 : the 18th International Congress on Acoustics, Kyoto International Conference Hall, 4-9 April, Kyoto, Japan. - Kyoto, Japan. - 499019151X ; , s. 297-300
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Konferensbidrag (refereegranskat)abstract
- Musical theatre singing requires the use of twovocal registers in the female voice. The voice source and subglottal pressure Pscharacteristics of these registers are analysed by inverse filtering. The relationship between Psand closed quotient Qclosed, peak-to-peak pulse amplitude Up-t-p, maximum flow declination rate MFDR and the normalised amplitude quotient NAQ were examined. Pswastypically slightly higher in chest than in head register . For typical tokens MFDR and Qclosed were significantly greater while NAQ and Up-t-p were significantly lower in chest than in head.
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| 8. |
- Björkner, Eva, et al.
(författare)
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Voice source differences between registers in female musical theater singers
- 2006
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 20:2, s. 187-197
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Tidskriftsartikel (refereegranskat)abstract
- Musical theater singing typically requires women to use two vocal registers. Our investigation considered voice source and subglottal pressure P-s characteristics of the speech pressure signal recorded for a sequence of /pae/ syllables sung at constant pitch and decreasing vocal loudness in each register by seven female musical theater singers. Ten equally spaced P-s values were selected, and the relationships between P-s and several parameters were examined; closed-quotient (Q(closed)), peak-to-peak pulse amplitude (Up-t-p), amplitude of the negative peak of the differentiated flow glottogram. ie, the maximum flow declination rate (MFDR), and the normalized amplitude quotient (NAQ) [Up-t-p/(TO*MFDR)], where TO is the fundamental period. P, was typically slightly higher in chest than in head register. As P, influences the measured glottogram parameters, these were also compared at an approximately identical P-s of 11 cm H2O. Results showed that for typical tokens, MFDR and Q(closed) were significantly greater, whereas Up-t-p and therefore NAQ were significantly lower in chest than in head.
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