| 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. |
- 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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| 3. |
- Laukkanen, Anne-Maria, et al.
(författare)
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High-speed registration of phonation-related glottal area variation during artificial lengthening of the vocal tract
- 2007
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Ingår i: Logopedics, Phoniatrics, Vocology. - : Informa UK Limited. - 1401-5439 .- 1651-2022. ; 32:4, s. 157-164
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Tidskriftsartikel (refereegranskat)abstract
- Vocal exercises that increase the vocal tract impedance are widely used in voice training and therapy. The present study applies a versatile methodology to investigate phonation during varying artificial extension of the vocal tract. Two males and one female phonated into a hard-walled plastic tube ( 2 cm), whose physical length was randomly pair-wise changed between 30 cm, 60 cm and 100 cm. High-speed image (1900 f/sec) sequences of the vocal folds were obtained via a rigid endoscope. Acoustic and electroglottographic signals (EGG) were recorded. Oral pressure during shuttering of the tube was used to give an estimate of subglottic pressure (P-sub). The only trend observed was that with the two longer tubes compared to the shortest one, fundamental frequency was lower, open time of the glottis shorter, and P-sub higher. The results may partly reflect increased vocal tract impedance as such and partly the increased vocal effort to compensate for it. In other parameters there were individual differences in tube length-related changes, suggesting complexity of the coupling between supraglottic space and the glottis.
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| 4. |
- Lehto, Laura, et al.
(författare)
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Comparison of two inverse filtering methods in parameterization of the glottal closing phase characteristics in different phonation types
- 2007
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Ingår i: Journal of Voice. - : Elsevier BV. - 0892-1997 .- 1873-4588. ; 21:2, s. 138-150
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Tidskriftsartikel (refereegranskat)abstract
- Inverse filtering (IF) is a common method used to estimate the source of voiced speech, the glottal flow. This investigation aims to compare two IF methods: one manual and the other semiautomatic. Glottal flows were estimated from speech pressure waveforms of six female and seven male subjects producing sustained vole /a/ in breathy, normal, and pressed phonation. The closing phase characteristics of the glottal pulse were parameterized using two time-based parameters: the closing quotient (C1Q) and the normalized amplitude quotient (NAQ). The information given by these two parameters indicates a strong correlation between the two IF methods. The results are encouraging in showing that the parameterization of the voice source in different speech sounds can be performed independently of the technique used for inverse filtering.
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| 5. |
- Sambeth, Anke, et al.
(författare)
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Sleeping newborns extract prosody from continuous speech
- 2008
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Ingår i: Clinical Neurophysiology. - : Elsevier BV. - 1872-8952 .- 1388-2457. ; 119:2, s. 332-341
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Behavioral experiments show that infants use both prosodic and statistical cues in acquiring language. However, it is not yet clear whether these prosodic and statistical tools are already present at birth. Methods: We recorded brain responses of sleeping newborns to natural sounds rich in prosody, namely singing and continuous speech, and to two impoverished manipulations of speech. A total of 11 newborns were presented with continuous speech, singing, and degraded speech, while MEG was recorded. Results: We found that a brain response elicited to the prosodically rich singing and continuous natural speech conditions decreased dramatically when the prosody in the speech was impoverished. Conclusions: We claim that this response is the indicator of the infants' sensitivity to prosodic cues in language, which is already present at birth during natural sleep. Significance: The indicators of detection of prosody may be crucial in assessing the normal and abnormal cortical function in newborns, especially of those infants at-risk for language problems.
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| 6. |
- Selamtzis, Andreas, 1984-
(författare)
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Analyses of voice and glottographic signals in singing and speech
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recent advances in machine learning and time series analysis techniques have brought new perspectives to a great number of scientific fields. This thesis contributes applications of such techniques to voice analysis, in an attempt to extract information on the vibration of the vocal folds as such, as well as on the radiated acoustic signal. The data that was analyzed in this work are acoustic recordings, electroglottographic (EGG) signals and transnasal high- speed videoendoscopic images. The data analysis techniques are primarily based on clustering, i.e., grouping of data based on similarity, and sample entropy analysis, i.e., quantifying the degree of irregularity in a given signal. The experiments were conducted so as to provide data for different types of vibratory behaviors (or vibratory states) of the vocal folds. Clustering was used in order to categorize in an unsupervised fashion these different vi- bratory states, based solely on the electroglottographic signal, or the glottal area waveform, or both. Sample entropy was utilized as an indicator of in- stabilities, when subjects produced voiced sounds using irregular vibratory patterns, such as register breaks, intermittent diplophonia, and other types of irregularities. The prominent role of sound pressure level and fundamental frequency motivated further study of the relationship between them and the shape of the electroglottographic waveform. Graphical representations were created to visualize the relationship between different vibratory behaviors with fundamental frequency and sound pressure level. The EGG waveform shape was seen to depend strongly on sound pressure level and somewhat less on fundamental frequency. In very soft phonation, the almost sinusoidal waveform of the EGG suggests that studying the EGG using clusters may give a better representation compared to conventional time-domain metrics. The paradigm of the clustering was later applied in synchronous recordings of electroglottogram and glottal area waveforms in professional tenor singers. Different vibratory states were classified successfully using clustering, and the electroglottogram was seen to be as good as the glottal area waveform for such a classification task. The last part of this work concerns voices from subjects with organic dysphonia. A study was dedicated to investigate how vowel context (sustained versus excerpted from speech) can affect the power of quantitative acoustic measures to discriminate dysphonic subjects from controls. Two acoustic voice quality measures were used: the cepstral peak prominence (smoothed) and sample entropy. The cepstral peak prominence (smoothed) showed better discriminatory power with excerpted vowels, while sample entropy with sustained vowels. Additionally, it was found that sample entropy was strongly correlated with cepstral peak prominence (smoothed) and with the perceptual quality of breathiness.
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| 7. |
- Teinonen, Tuomas, et al.
(författare)
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Statistical language learning in neonates revealed by event-related brain potentials
- 2009
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Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background: Statistical learning is a candidate for one of the basic prerequisites underlying the expeditious acquisition of spoken language. Infants from 8 months of age exhibit this form of learning to segment fluent speech into distinct words. To test the statistical learning skills at birth, we recorded event-related brain responses of sleeping neonates while they were listening to a stream of syllables containing statistical cues to word boundaries. Results: We found evidence that sleeping neonates are able to automatically extract statistical properties of the speech input and thus detect the word boundaries in a continuous stream of syllables containing no morphological cues. Syllable-specific event-related brain responses found in two separate studies demonstrated that the neonatal brain treated the syllables differently according to their position within pseudowords. Conclusion: These results demonstrate that neonates can efficiently learn transitional probabilities or frequencies of co-occurrence between different syllables, enabling them to detect word boundaries and in this way isolate single words out of fluent natural speech. The ability to adopt statistical structures from speech may play a fundamental role as one of the earliest prerequisites of language acquisition.
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