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

Abstract

Purpose: The average fundamental frequency separation (∆ f o ) 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 f o characteristics that may not be typical of realistic acoustic scenarios. This study investigated to what extent the effect of ∆ f o generalizes to more real-life speech. Methods: 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 ∆ f o s . Results: Compared to previous studies that addressed the same experimental scenario with less realistic speech materials, the present results showed only a moderate effect of ∆ f o at negative TMRs and a negligible effect at positive TMRs. An analysis of the employed stimuli showed that a large ∆ f o effect on the target speech intelligibility is only observed when the competing sentences have highly synchronous f o trajectories, which is typical of the artificial speech materials employed in previous studies. Conclusion: Overall, the present results suggest a relatively small effect of ∆ f o on the intelligibility of real-life speech, as compared to previously employed artificial speech, in two-competing-sentences conditions.