The Role of Average Fundamental Frequency Difference on the Intelligibility of Real-Life Competing Sentences.

Abstract

The average fundamental frequency separation (∆fo) between two competing voices has been shown to provide an important cue for target-speech intelligibility. However, some of the previous investigations used speech materials with linguistic properties and fo characteristics that may not be typical of realistic acoustic scenarios. This study investigated to what extent the effect of ∆fo generalizes to more real-life speech. Real-life sentences and a well-controlled method for manipulating the acoustic stimuli were employed. Fifteen young normal-hearing native Danish listeners were tested in a two-competing-voices sentence recognition task at several target-to-masker ratios (TMRs) and ∆fos. Compared to previous studies that addressed the same experimental scenario with less realistic speech materials, the present results showed only a moderate effect of ∆fo at negative TMRs and a negligible effect at positive TMRs. An analysis of the employed stimuli showed that a large ∆fo effect on the target speech intelligibility is only observed when the competing sentences have highly synchronous fo trajectories, which is typical of the artificial speech materials employed in previous studies. Overall, the present results suggest a relatively small effect of ∆fo on the intelligibility of real-life speech, as compared to previously employed artificial speech, in two-competing-sentences conditions.