Voice perception on a voice messaging app: implications for Forensic Phonetics

Abstract

This study aims to analyze the effects of a voice messaging app transmission on voice quality and voice dynamics perception and to discuss how they can impact forensic analysis. The study design comprised a perceptual experiment on pairs of stimuli from 10 Brazilian speakers recorded directly by a digital recorder and over WhatsApp voice messages. A group of four voice-specialized judges has assessed the stimuli set by means of the Vocal Profile Analysis (VPA), which comprises both voice quality and voice dynamics settings. Data analysis has included reliability measures, and the spatial arrangement of the stimuli pairs through a multidimensional scaling technique (MDS). The settings mainly correlated to MDS dimensions were “Lowered Larynx”, “Tense Larynx” and “Creaky” as well as “Pitch Mean” and “Pitch Extensive Range”. The voice quality settings were less affected by the recording condition, since the perceptual distances between stimuli pairs in this group were lower than those related to voice dynamics. However, the attested perceptual differences are not limited to stimuli acoustic quality only since none of the MDS perceptual dimensions could separate the recording conditions. Implications for Forensic Phonetics are considered.