Perceptual sensitivity to first harmonic amplitude in the voice source

Abstract

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.

Relation of Perceived Breathiness to Laryngeal Kinematics and Acoustic Measures Based on Computational Modeling

“…This is a measure of the spectral slope of the low frequencies, and correction of the harmonic amplitudes for the effect of the first resonance of the vocal tract (F1) (Hanson, 1997) or multiple resonances (Iseli, Shue, & Alwan, 2007) has been advocated as an inverse filter to better approximate the glottal flow spectrum and compare results across vowels and speakers. H1*-H2* (the asterisk denoting corrected amplitudes) has been shown to relate to variability in the glottal pulse and spectral shapes (Kreiman, Gerratt, & Antoñanzas - Barroso, 2007), to be perceivable by listeners in the range produced by speakers (Kreiman & Gerratt, 2010), and H1-H2 can be used as a primary cue to phonemic breathiness (Esposito 2010). This measure, though, has been shown to be weak in its ability to differentiate degree of breathiness of normal and voice disordered subjects (Klatt & Klatt, 1990; Hillenbrand, Cleveland, & Erickson, 1994; Hillenbrand & Houde, 1996; Hartl et al, 2003; Holmberg et al, 2003; Shrivastav, 2003) and is influenced by nasality (Simpson, 2012).…”

Effects of native language on perception of voice quality

“…She speculates that the linguistic status of the phonation contrast is at the heart of this difference, but her experimental design did not permit conclusions about causation. Similarly, Kreiman and Gerratt (2010) found that Mandarin listeners were significantly more sensitive to changes in H1-H2 than were English listeners (just-noticeable difference = 2.72 dB, vs. 3.61 dB). They proposed two possible explanations for this finding.…”

Perceptual sensitivity to a model of the source spectrum

“…Previous work has demonstrated that listeners are sensitive to individual components of the model, particularly H1-H2 (Kreiman & Gerratt 2010) and to higher frequencies (Kreiman & Gerratt 2012). Garellek et al (2013) also found that changes to both H1-H2 and H2-H4 (but not to H4-2kHz or 2kHz-5kHz) were important for the perception of contrastive breathiness in White Hmong.…”

“…The voices were inverse-filtered and copy-synthesized to obtain a synthetic copy of the original voice that was a close perceptual match to the original. For more details of the copy-synthesis process, see Javkin et al (1987) and Kreiman et al (2010). In brief, the synthesizer's sampling rate was fixed at 10 kHz.…”

“…One approach to this problem has been to establish links between acoustic aspects of the source signal and voice quality. A psychoacoustic model of the voice source spectrum has been proposed in which unique acoustic parameters combine to capture the overall voice quality (Kreiman & Gerratt, 2010;Kreiman et al, 2011;Kreiman & Gerratt, 2012, Garellek et al 2013. This model has four spectral slope parameters: H1-H2 (the amplitude difference between the first and second harmonics), H2-H4 (the amplitude difference between the second and fourth harmonics), H4-2kHz (the amplitude difference between the fourth harmonic and the harmonic nearest 2000 Hz), and 2kHz-5kHz (the amplitude difference between the harmonic nearest 2000 Hz and that nearest 5000 Hz).…”