Article
A Model Of Binaural Interaction Based On Two Correlators (en)
* Presenting author
Abstract:
Most classic models of binaural processing are partly built on assumptions that have been challenged or even contradicted by physiologic or psychoacoustic data. We show that, by abandoning unproven assumptions, two cross-correlating units can already account for 98% of the variance of over 300 tone-in-noise detection thresholds across eight studies, by optimizing three free parameters. From there, new assumptions have to be made, en route to extending the “two correlator concept” to a comprehensive binaural model. The first assumption is a mechanism that introduces incoherence interference across frequency channels. It reduces interaural coherence discrimination sensitivity if less coherent channels exist in spectral proximity. Incoherence interference differs from the classic assumption of wider binaural filters, since it has no effect if the masker coherence is constant across frequency bands. It resolves the inconsistency that accounting for some datasets requires wide filters while others require narrow filters. Within the classic model construct, so-called delay-lines were needed to simulate residual binaural sensitivity, even at large interaural time differences. Using peripheral filter bandwidths for binaural models, however, renders the delay-lines unnecessary. It is shown that the increased temporal coherence of narrow filters serves the same purpose but with fewer assumptions and contradictions.