Predictive processing increases intelligibility of acoustically distorted speech: Behavioral and neural correlates.

Introduction: We examined which brain areas are involved in the comprehension of acoustically distorted speech using an experimental paradigm where the same distorted sentence can be perceived at different levels of intelligibility. This change in intelligibility occurs via a single intervening presentation of the intact version of the sentence, and the effect lasts at least on the order of minutes. Since the acoustic structure of the distorted stimulus is kept fixed and only intelligibility is varied, this allows one to study brain activity related to speech comprehension specifically.

Estimating the spectral tilt of the glottal source from telephone speech using a deep neural network.

Estimation of the spectral tilt of the glottal source has several applications in speech analysis and modification. However, direct estimation of the tilt from telephone speech is challenging due to vocal tract resonances and distortion caused by speech compression. In this study, a deep neural network is used for the tilt estimation from telephone speech by training the network with tilt estimates computed by glottal inverse filtering.

Previous exposure to intact speech increases intelligibility of its digitally degraded counterpart as a function of stimulus complexity.

Recent studies have shown that acoustically distorted sentences can be perceived as either unintelligible or intelligible depending on whether one has previously been exposed to the undistorted, intelligible versions of the sentences. This allows studying processes specifically related to speech intelligibility since any change between the responses to the distorted stimuli before and after the presentation of their undistorted counterparts cannot be attributed to acoustic variability but, rather, to the successful mapping of sensory information onto memory representations. To estimate how the complexity of the message is reflected in speech comprehension, we applied this rapid change in perception to behavioral and magnetoencephalography (MEG) experiments using vowels, words and sentences.

Signal-to-noise ratio adaptive post-filtering method for intelligibility enhancement of telephone speech.

Post-filtering can be utilized to improve the quality and intelligibility of telephone speech. Previous studies have shown that energy reallocation with a high-pass type filter works effectively in improving the intelligibility of speech in difficult noise conditions. The present study introduces a signal-to-noise ratio adaptive post-filtering method that utilizes energy reallocation to transfer energy from the first formant to higher frequencies.