A joint framework for blind prediction of binaural speech intelligibility and perceived listening effort.

Speech perception is strongly affected by noise and reverberation in the listening room, and binaural processing can substantially facilitate speech perception in conditions when target speech and maskers originate from different directions. Most studies and proposed models for predicting spatial unmasking have focused on speech intelligibility. The present study introduces a model framework that predicts both speech intelligibility and perceived listening effort from the same output measure. The framework is based on a combination of a blind binaural processing stage employing a blind equalization cancelation (EC) mechanism, and a blind backend based on phoneme probability classification. Neither frontend nor backend require any additional information, such as the source directions, the signal-to-noise ratio (SNR), or the number of sources, allowing for a fully blind perceptual assessment of binaural input signals consisting of target speech mixed with noise. The model is validated against a recent data set in which speech intelligibility and perceived listening effort were measured for a range of acoustic conditions differing in reverberation and binaural cues [Rennies and Kidd (2018), J. Acoust. Soc. Am. 144, 2147-2159]. Predictions of the proposed model are compared with a non-blind binaural model consisting of a non-blind EC stage and a backend based on the speech intelligibility index. The analyses indicated that all main trends observed in the experiments were correctly predicted by the blind model. The overall proportion of variance explained by the model (R² = 0.94) for speech intelligibility was slightly worse than for the non-blind model (R² = 0.98). For listening effort predictions, both models showed lower prediction accuracy, but still explained significant proportions of the observed variance (R² = 0.88 and R² = 0.71 for the non-blind and blind model, respectively). Closer inspection showed that the differences between data and predictions were largest for binaural conditions at high SNRs, where the perceived listening effort of human listeners tended to be underestimated by the models, specifically by the blind version.

Can You Hear Out the Melody? Testing Musical Scene Perception in Young Normal-Hearing and Older Hearing-Impaired Listeners.

It is well known that hearing loss compromises auditory scene analysis abilities, as is usually manifested in difficulties of understanding speech in noise. Remarkably little is known about auditory scene analysis of hearing-impaired (HI) listeners when it comes to musical sounds. Specifically, it is unclear to which extent HI listeners are able to hear out a melody or an instrument from a musical mixture. Here, we tested a group of younger normal-hearing (yNH) and older HI (oHI) listeners with moderate hearing loss in their ability to match short melodies and instruments presented as part of mixtures. Four-tone sequences were used in conjunction with a simple musical accompaniment that acted as a masker (cello/piano dyads or spectrally matched noise). In each trial, a signal-masker mixture was presented, followed by two different versions of the signal alone. Listeners indicated which signal version was part of the mixture. Signal versions differed either in terms of the sequential order of the pitch sequence or in terms of timbre (flute vs. trumpet). Signal-to-masker thresholds were measured by varying the signal presentation level in an adaptive two-down/one-up procedure. We observed that thresholds of oHI listeners were elevated by on average 10 dB compared with that of yNH listeners. In contrast to yNH listeners, oHI listeners did not show evidence of listening in dips of the masker. Musical training of participants was associated with a lowering of thresholds. These results may indicate detrimental effects of hearing loss on central aspects of musical scene perception.