Integrated software for analysis and synthesis of voice quality

Gerratt

2010

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Little is known about the perceptual importance of changes in the shape of the source spectrum, although many measures have been proposed and correlations with different vocal qualities ͑breathiness, roughness, nasality, strain…͒ have frequently been reported. This study investigated just-noticeable differences in the relative amplitudes of the first two harmonics ͑H1-H2͒ for speakers of Mandarin and English. Listeners heard pairs of vowels that differed only in the amplitude of the first harmonic and judged whether or not the voice tokens were identical in voice quality. Across voices and listeners, just-noticeable-differences averaged 3.18 dB. This value is small relative to the range of values across voices, indicating that H1-H2 is a perceptually valid acoustic measure of vocal quality. For both groups of listeners, differences in the amplitude of the first harmonic were easier to detect when the source spectral slope was steeply falling so that F0 dominated the spectrum. Mandarin speakers were significantly more sensitive ͑by about 1 dB͒ to differences in first harmonic amplitudes than were English speakers. Two explanations for these results are possible: Mandarin speakers may have learned to hear changes in harmonic amplitudes due to changes in voice quality that are correlated with the tones of Mandarin; or Mandarin speakers' experience with tonal contrasts may increase their sensitivity to small differences in the amplitude of F0 ͑which is also the first harmonic͒.

Section: A Stimulimentioning

confidence: 99%

Perceptual sensitivity to first harmonic amplitude in the voice source

Gerratt

2010

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“…For this reason, formant frequencies and bandwidths were derived through analysis-by-synthesis. Using the UCLA voice synthesizer (Kreiman et al, 2010a), the original voice samples were copy-synthesized using the following procedure. Because apparent harmonic amplitudes can vary depending on formant frequencies and bandwidths as well as source characteristics, vowel quality was first matched to the target, before the source was altered.…”

Section: Acoustic Measurementsmentioning

confidence: 99%

Variability in the relationships among voice quality, harmonic amplitudes, open quotient, and glottal area waveform shape in sustained phonation

Shue²,

Chen³

et al. 2012

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Increases in open quotient are widely assumed to cause changes in the amplitude of the first harmonic relative to the second (H1*–H2*), which in turn correspond to increases in perceived vocal breathiness. Empirical support for these assumptions is rather limited, and reported relationships among these three descriptive levels have been variable. This study examined the empirical relationship among H1*–H2*, the glottal open quotient (OQ), and glottal area waveform skewness, measured synchronously from audio recordings and high-speed video images of the larynges of six phonetically knowledgeable, vocally healthy speakers who varied fundamental frequency and voice qualities quasi-orthogonally. Across speakers and voice qualities, OQ, the asymmetry coefficient, and fundamental frequency accounted for an average of 74% of the variance in H1*–H2*. However, analyses of individual speakers showed large differences in the strategies used to produce the same intended voice qualities. Thus, H1*–H2* can be predicted with good overall accuracy, but its relationship to phonatory characteristics appears to be speaker dependent.

“…However, these concerns have become largely irrelevant. Computational constraints and artifacts are no longer common Kreiman et al, 2010), and much progress has been made in determining spectral parameters that vary across voices and to which listeners are sensitive (Kreiman et al, 2007a;Kreiman et al, 2014). Both approaches (modeling in the time domain vs in the spectral domain) share the goal of mapping between voice production and perception; but in the second case the functional significance of the magic moments or places is established a priori, ensuring that results will be perceptually meaningful, however complex the associations between physical and psychoacoustic events prove to be.…”

Section: General Discussion and Conclusionmentioning

confidence: 99%

“…Estimates of the sources of these voice samples were then derived via inverse filtering using the method described by Javkin et al (1987). Because inverse filtering is imprecise at best (e.g., Alku, 2011), these estimates were corrected using analysis-by-synthesis (AbS) to create synthetic voice samples that precisely matched the quality of the original natural voice samples (Kreiman et al, 2010), as follows. The spectrum of a single representative source pulse extracted via inverse filtering was calculated and used to model the harmonic part of the voice source.…”

Section: Modeling Glottal Pulses a Voice Samplesmentioning

confidence: 99%

Perceptual evaluation of voice source models

Garellek

Chen

et al. 2015

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Models of the voice source differ in their fits to natural voices, but it is unclear which differences in fit are perceptually salient. This study examined the relationship between the fit of five voice source models to 40 natural voices, and the degree of perceptual match among stimuli synthesized with each of the modeled sources. Listeners completed a visual sort-and-rate task to compare versions of each voice created with the different source models, and the results were analyzed using multidimensional scaling. Neither fits to pulse shapes nor fits to landmark points on the pulses predicted observed differences in quality. Further, the source models fit the opening phase of the glottal pulses better than they fit the closing phase, but at the same time similarity in quality was better predicted by the timing and amplitude of the negative peak of the flow derivative (part of the closing phase) than by the timing and/or amplitude of peak glottal opening. Results indicate that simply knowing how (or how well) a particular source model fits or does not fit a target source pulse in the time domain provides little insight into what aspects of the voice source are important to listeners.