Effects of Transmitted Speech Bandwidth on Subjective Assessments of Speaker Characteristics

The first impression of unknown speakers in telephone calls can determine our disposition towards our interlocutors and the conversation. While it has been asserted that narrowband communications (300-3,400 Hz) can severely affect perceived speech quality in comparison to wideband (50-7,000 Hz), transmission channel effects have been practically disregarded in the literature concerning the perception of speaker attributes or traits. In this study, listening tests have been conducted with 23 participants who were presented with narrowband and wideband speech and rated interpersonal speaker characteristics on a semantic differential questionnaire of 34 items. For each item, we evaluate how the subjective ratings correlate with perceived speech quality and whether they are affected by channel bandwidth, focusing on differences in speaker gender and in their warmth-attractiveness. The effects found, primarily on speakers' warmth, confidence and competence, can be explained by the alterations of pitch frequency variations caused by narrowband transmissions.