Predicting masking release of lateralized speech

Poster presented at ISAAR 2015, in Nyborg, DK.

"Locsei et al. [2015, Speech in Noise Workshop, Copenhagen, pp.46] measured speech reception thresholds (SRTs) in anechoic conditions where the target speech and the maskers were lateralized using interaural time delays. The maskers were speech-shaped noise (SSN) and reversed babble (RB) with two, four, or 8 talkers. For a given interferer type, the number of maskers presented on the target’s side was varied, such that none, some, or all maskers were presented on the same side as the target. In general, SRTs did not vary significantly when at least one masker was presented on the same side as the target. The largest masking release (MR) was observed when all maskers were on the opposite side of the target. The data could be accounted for using a binaural extension of the sEPSM model [Jørgensen and Dau, J. Acoust. Soc. Am. 130(3), 1475–1487], which uses a short-term equalization–cancellation process to model binaural unmasking. The modeling results suggest that, in these conditions, explicit top-down processing, such as streaming, is not required and that the MR could be fully accounted for by only bottom-up processes. However, independent access to the noisy speech and the noise alone by the model could be considered as implicit streaming and should therefore be taken into account when considering “bottom-up” models."