# Auditory Perception of Impulsiveness and Tonality in Vocal Fry
###### Abstract
In particular, temporal variations of voice quality are observed in connected speech, which makes the study of the short-term segmental context relevant. In this study, we first seek to bridge the knowledge gap that exists between the levels of voice production and perception. In particular, we aim to disentangle the effects of vibration frequency Fo, open quotient Qo, and pulse skewness Qs on perceived impulsiveness, tonality, and binary fry. We provide quantitative probabilistic models for the dependencies of auditory fry on these voice production parameters. Second, in order to address auditory perception, we apply [PERSON] et al. 's loudness model with a view to predicting temporal auditory segregation of individual glottal pulses by analyzing the peak prominence in curves of loudness over time, which we term loudness peak prominence (LPP) [28]. Third, we aim to investigate whether graduations of fry exist. In particular, we test whether perceived impulsiveness is a proxy for perceived binary fry and whether evidence of graduations of fry exists in LPP. Fourth, we monitor the perceived naturalness of synthetic stimuli to investigate whether (i) the synthesizer is capable of producing voice signals that sound similar to human-produced vocal fry signals, and (ii) the control parameters of the synthesizer must be confined so that the stimuli sound similar to human-produced voice. Fifth, we investigate if the internal reference standards listeners use for distinguishing fry from modal voice are influenced by the short-term context. Finally, we will find that it is necessary to discuss, whether these standards are fixed for each listener, and if the standards may be adjusted by anchoring. Clinical long-term perspectives include the following. First, improving the understanding of the relations between voice production and perception lays the groundwork for improving clinical treatment for improving perceptual voice quality. Second, acquisition of knowledge of the properties of auditory reference standards of listeners is important for improving the current state of voice quality assessment. Finally, another clinical long-term perspective of this work may be the distinction between pathological and non-pathological fry. The first experiment addresses the effect of vocal frequency Fo, open quotient Qo, and pulse skewness Qs on the perception of vocal fry in vowels with temporally homogeneous voice quality. We use as test stimuli synthesized vowels for which the studied parameters are constant. Our hypotheses are that perceived impulsiveness and the probability of perceived binary fry increase and perceived tonality decreases with (i) decreasing Fo, (ii) decreasing Qo, and (iii) increasing Qs. In a second experiment, we test whether the short-term context affects the perception of fry. Vowels are used as stimuli with high-low-high changes in the frequency and the open quotient. We hypothesize that increasing the glottal parameter variation favors the perception of fry. That is, when the difference \(\Delta\)Fo and the difference \(\Delta\)Qo increase, the stimuli are more likely to be rated as vocal fry and as impulsive and less likely to be rated as tonal. The remainder of the article is structured as follows. The synthesizer is introduced and the two listening experiments are outlined in Section 2. Section 3 presents the results. Section 4 summarizes the study, and discusses the results and the limitations of the study. Finally, Section 5 concludes the article.