Mika Ito

The effect of the spectral shape changes on voice perception

Researchers have long known that the shape of the vocal source spectrum is an important determinant of vocal quality, but the details regarding the importance of individual spectral features remains unclear. Previous research indicates four spectral features, H1‐H2, the spectral slope above 4 kHz, the slope from 1.5–2 kHz, and the slope from 2–4 kHz, account for virtually all the variability in spectral shapes. The present study provides preliminary evidence about the perceptual importance of these four features. Four series of stimuli were synthesized for each spectral parameter, in which that parameter varied in small steps. Because the perceptual salience of source parameters depends on F0 and on the spectrum of the inharmonic part of the source, series differed in the sex of the speaker (male/female) and in the NSR (noise‐free/very noisy). Listeners heard all possible pairs of voices within each series and were asked to determine whether stimuli were the same or different. We hypothesize that listener...

Relationship between perceived politeness and spectral characteristics of voice

This study investigates the role of voice quality in perceiving politeness under conditions of varying relative social status among Japanese male speakers. The work focuses on four important methodological issues: experimental control of sociolinguistic aspects, eliciting natural spontaneous speech, obtaining recording quality suitable for voice quality analysis, and assessment of glottal characteristics through the use of non‐invasive direct measurements of the speech spectrum. To obtain natural, unscripted utterances, the speech data were collected with a Map Task. This methodology allowed us to study the effect of manipulating relative social status among participants in the same community. We then computed the relative amplitudes of harmonics and formant peaks in spectra obtained from the Map Task recordings. Finally, an experiment was conducted to observe the alignment between acoustic measures and the perceived politeness of the voice samples. The results suggest that listeners’ perceptions of polit...

The effect of acoustic context and scale resolution on judgments of voice quality

Anchored protocols (in which listeners match test stimuli to fixed examples of different scale levels) control response variability in voice‐quality judgment tasks, and may be clinically applicable because they are also easy to use. Successful application requires that two conditions hold. First, listeners must be able to isolate the target quality in the natural pathologic voice and match the level of that quality to levels present in a different acoustic context (the anchors). Second, the anchored scales resolution must be sufficient for listeners to make consistent judgments about stimuli that fall between anchors. To examine these issues, listeners judged noise levels for 40 test voices in four tasks. Two were anchored tasks (limited‐scale resolution), in which the synthetic anchor voices matched the test voice (matched acoustic environment) in one condition and differed from the test voice environment in a second condition (traditional approach). Tasks three and four used the method of adjustment (fi...