Acoustic Correlates of Glottal Gaps

During speech production, the vocal folds may not close completely. The resulting glottal gap (GG) or incomplete glottal closure has not been systematically studied in terms of GG acoustic and/or perceptual consequences. This paper uses high-speed imaging to investigate the relationship between GG area, source parameters, acoustic measures, and voice quality for 6 subjects. Results showed that the cepstral peak prominence (CPP) and the harmonics-to-noise ratio (HNR) are affected by GG area, indicating the presence of more spectral noise with increasing GG area. Analysis of a glide phonation from breathy to pressed for one female speaker showed that measures H∗ 1 − H∗ 2 and H∗ 1−A3 were positively correlated with GG area under a steady fundamental frequency (F0). In some phonatory modes, increasing F0 may reduce the amplitude of vocal folds vibration, increase GG area, and produce a lower spectral tilt due to significant aspiration noise, leading to a negative correlation between GG area and the spectral tilt measure H∗ 1 −A3.